Essen borehole (001E0071)
Description and interpretation
Pieter Laga
November, 2006
Part of hydro/05neb campaign
Customer and Scientific co-ordinator : SCKCEN
Master of Works : ONDRAF/NIRAS
TABLE OF CONTENTS
1. General information
2. Comments
2.1. Comment on the quality of the cores
2.2. Comment on the description
2.3. Comment on the interpretations
3. Geological description
4. Geological interpretation
4.1. Overview
4.2. Comment
4.2.1.The Pleistocene and Neogene Formations
4.2.2.The Oligocene Formations
4.2.3.The Eocene Formations
ANNEX : Photos of cores
References :
Lie S.F., Broothaers M., and Uyttendaele D. (2006) Drilling and geological report of the Essen-1 well. 1-122. Faninbel report to ONDRAF/NIRAS, Lille, Belgium.
1. General information (extract archive GSB)
Map number.: 001E
Sheet: ESSEN
Borehole number.: 071 (VII,d)
Type of Drilling: Core-drilling with installation of piezometers
Topographic Map: 1/8
Drilling date: Essen
Postal code.: 2910
Address: Watertoren Pidpa, Oude Baan 61, 2910 Essen
Customer: SCKCEN (ONDRAF/NIRAS)
Drilling company: Smet-GWT
Drilling date: January-February 2006
Topography: Studiegroep Omgeving
Samples by:
Drilling technique: straight flush and coring
Lengths and diameters: drilling from Ø 580 mm to 280 mm, core Ø 100 mm
Water levels:
First level:
Static level:
During pumping:
Pumping rate:
"Waterzaak" form number:
Total depth: 508.55 m BDT (below drilling table)
Sample store location: at the SCKCEN (Belgian Nuclear Research Centre)1
Ground surface / ref. level: + 14.871 m a.s.l. (or m TAW); drilling table is 0.20 m above ground surface
X: 156662.5 m
Y: 238672.2 m
NIS code: 11016
2. Comments
2.1. Comment on the quality of the cores
The quality of the cores is very good in the clay and in the very clayey sand sections. The cores are usually longer than the cored length, probably due to the extension of the core sediment in the core-barrel (swelling of the clay).
In more sandy and sand section, the length of the cores is often shorter than the cored length and the cores are often disturbed (presence of open fissures, cracks and voids). In some cases, the sandy core is disturbed by fluidity of the sand (after putting down cores with a water saturated sediment in horizontal position).
2.2. Comment on the description
The description is based on the upper longitudinal section of the cores. The cores were indeed longitudinally sawed in two unequal parts, the upper one, being the thinnest part (roughly one third), was available for description, and the lower part was immediately packed under vacuum conditions.
As this material should stay available for many people, the cores couldn't be investigated destructively. For instance, slickenslide observations are mentioned only in the core numbers 86 and 106. However, in nearly all the pure heavy (wax-like) clay, this feature can be present, but a systematic search for these slickenslides should cause a destruction of the concerned cores. It is difficult to say if these features are natural or artefacts. Probably they are due to compaction and are of minor importance.
2.3. Comment on the interpretations
Preliminary remarks
Although cores should provide the best material for geological descriptions, the interpretation of a cored borehole, can not be given without any doubt.
In general, at greater depths, the characteristics of lithologic units are different than in outcrops (alteration effects near the surface and lateral facies changes at greater distances from the corresponding outcrop zone).
Despite the performance of the drilling and coring operations during the drilling of the Essen borehole, the recovery is not 100 %. Especially in borehole sections with sudden changes of the lithology and the presence of sandstone concretions or layers in unconsolidated sediments, core losses occurred.
In addition, full cylindrical sections of cores of 10, 18, 20 or 40 cm were cut off for laboratory research even complete cores (of 1 m) were sent to the geomechanic laboratory and were therefore not available. Globally that means that 30 % of the cored section is not covered by a core description. Although this situation is inevitable in the given concept of research boreholes, nevertheless it means that important lithologic features can have been missed and that the reliability of the interpretation is diminished.
In many cases, the geophysical well logs can meet this loss of information. However, the actual printouts of the logs without changes in scale, do not allow to observe minor but important features of the usual log configuration in the investigated geological units.
For all these reasons, changes in the lithostratigraphic interpretation may necessarily be made once geophysical logs at a scale better adapted to the natural variability of the sediment are available and after completion of the paleontologic and the sedimentologic investigations.
3. Geological description
Description of cuttings
ref. : Lie S.F., Broothaers M., and Uyttendaele D. (2006) Drilling and geological report of the Essen-1 well. 1-122. Faninbel report to ONDRAF/NIRAS, Lille, Belgium.
Depth(m) Lithology , Colour , Grain-size (for sand only) , Glauconite content
Descrition/Remarks
Samples were described when wet.
00.00 - 00.50 Soil, dark brown
no cuttings preserved
00.50 - 02.00 Sand, brown , vf
contamination with dark brown soil material
02.00 - 04.00 Sand, brown , vf
04.00 - 06.00 Sand, brown-grey , f
traces of black organic material
06.00 - 06.00 Sand, grey , f
08.00 - 10.00 Sand, grey , f
10.00 - 11.00 Sand, grey , vf
12.20 - 13.00 Sand, grey , f-vf
angular stone fragments
13.50 - 15.30 Sand, light grey , f-vf
angular stone fragments
15.30 - 16.30 Sand, grey , vf
stone fragments, few micas, traces of black organic material
16.30 - 18.30 Sand , grey , f
few micas, traces of black organic material
18.30 - 19.20 Sand, grey ,f
some micas, wood fragments, stone fragments
19.20 - 20.20 Sand, grey , f
20.20 - 22.00 Sand, grey , f
few small wood fragments, few micas
22.00 - 23.00 Sand, grey , f-vf
small, wood fragments, micas
23.00 - 24.00 Sand, grey , f-vf
small, wood fragments, micas
24.00 - 25.00 Sand, grey , f
wood fragments, some micas
25.00 - 26.00 Sand , grey , f
wood fragments, micas
26.00 - 27.00 Sand, grey , vf
wood fragments, micas
27.00 - 28.00 Sand, grey , f
wood fragments, micas
28.00 - 29.00 Sand, grey , f
wood and stone fragments, micas
29.00 - 30.00 Sand, grey , vf
traces of black organic material, large wood fragment, some micas, stone fragments (0,5-1cm)
30.00 - 31.00 Sand, grey , vf
few traces of black organic material, wood fragments, some micas
31.00 - 32.00 Sand, grey , vf
few traces of black organic material; large wood fragment; some micas
32.00 - 33.00 Sand, grey , f
few traces of black organic material; small wood fragments; few cuttings
33.00 - 34.00 Sand, grey , f
few traces of black organic material; small wood/plant fragments
34.00 - 35.00 Sand, grey , f
few traces of black organic material; small wood/plant fragments
35.00 - 36.00 Sand, grey , f
few traces of black organic material; small wood/plant fragments
36.00 - 37.00 Sand, grey , f
few traces of black organic material; small wood/plant fragments
37.00 - 38.00 Sand, grey , f
few traces of black organic material
38.00 - 40.00 Sand, grey , f
some traces of black organic material
40.00 - 41.00 Sand, grey , f
41.00 - 42.00 Sand, grey , f
few traces of black (organic) material
42.00 - 43.00 Sand, grey , f
few cuttings, few traces of black (organic) material
43.00 - 44.00 Sand, grey , f
few cuttings, traces of black (organic) material
44.00 - 45.00 Sand, grey , f
few cuttings, traces of black (organic) material
45.00 - 46.00 Sand, grey , f
traces of black (organic) material
46.00 - 47.00 Sand, grey , f
47.00 - 48.00 Sand, grey , f
48.00 - 49.00 Sand, grey , f
49.00 - 50.00 Sand, grey , f
50.00 - 52.00 Sand, grey
52.00 - 55.00 Sand, grey , f
55.00 - 56.00 Sand, grey , f
traces of black (organic!?) material
56.00 - 57.00 Sand, grey , f
traces of black (organic!?) material
57.00 - 59.00 Sand, grey , f
59.00 - 60.00 Sand, grey , m-f
pure sand vs. 60-61
60.00 - 61.00 Sand, grey , m-c
few cuttings, shell fragments
61.00 - 62.00 Sand, grey , m-c
few cuttings, shell fragments
62.00 - 63.00 Sand, grey , m-c
shell fragments
63.00 - 64.00 Sand, grey , m-c, traces
few shell fragments
64.00 - 65.00 Sand, grey , m-c, traces
few cuttings, few shell fragments
65.00 - 66.00 Sand, grey , m-c, traces
few shell fragments
66.00 - 67.00 Sand, grey , m, traces
few shell fragments
67.00 - 68.00 Sand, grey , m, traces
few shell fragments
68.00 - 69.00 Sand, grey , m, ,traces
few shell fragments
69.00 - 71.00 Sand, light greenish grey , f , very low-low
shell fragments
71.00 - 72.00 Sand, light greenish grey , f, very low
shell fragments
72.00 - 73.00 Sand, light greenish grey , f, very low-traces
shell fragments
73.00 - 74.00 Sand, light greenish grey , f, traces
shell fragments
74.00 - 75.00 Sand, light greenish grey , f, traces
shell fragments
75.00 - 76.00 Sand, light greenish grey , m-f, traces
shell fragments
76.00 - 77.00 Sand, light greenish grey , m-f, traces
shell fragments
77.00 - 78.00 Sand, light greenish grey , m, traces
shell fragments
78.00 - 79.00 Sand, light greenish grey , m, traces
shell fragments
79.00 - 80.00 Sand, light greenish grey , f, traces
few cuttings, shell fragments
80.00 - 81.00 Sand, light greenish grey , f, traces
few cuttings, shell fragments
81.00 - 82.00 Sand, light greenish grey , f, traces
few cuttings, shell fragments
82.00 - 84.00 Sand, light greenish grey , f-m, low
few cuttings, shell fragments
84.00 - 86.00 Sand, light greenish grey , f-m, low
well sorted
86.00 - 87.00 Sand, light greenish grey , f-m, low
shell fragments
87.00 - 88.00 Sand, light greenish grey , m, low
88.00 - 89.00 Sand, light greenish grey , m, low
89.00 - 90.00 Sand, greenish grey , f, traces
few cuttings, a few shell fragments
90.00 - 91.00 Sand, greenish grey , f, traces
few cuttings
91.00 - 93.00 Sand, greenish grey , f, traces,
few cuttings, a few shell fragments
93.00 - 95.00 Sand, green , m, moderate-high
95.00 - 96.00 Sand, green , m, moderate-high
poorly sorted
96.00 - 97.00 Sand, green , m, moderate-high
poorly sorted
97.00 - 98.00 Sand, light green , m-c, moderate-low
poorly sorted
98.00 - 99.00 Sand, grey-green , m, very low
few cutting
99.00 - 100.00 Sand, grey-green , m, very low
few cuttings
100.00 - 101.00 Sand, grey-green , m, very low
few cuttings, poorly sorted, shell fragments
101.00 - 103.00 Sand, grey-green , c, very low
few cuttings, poorly sorted, shell fragments
103.00 - 104.00 Sand, dark green , m-f, high
moderately sorted
104.00 - 105.00 Sand, green , m, high
moderately sorted
105.00 - 107.00 Sand, green , m
moderate-high
107.00 - 108.00 Sand, light green , m
moderate
108.00 - 110.00 Sand, grey , c, low
110.00 - 111.00 Sand, grey , c, low
111.00 - 112.00 Sand, grey , c, very low
few cuttings, shell fragments
112.00 - 113.00 Sand, grey , c, very low
few cuttings, shell fragments
113.00 - 114.00 Sand, grey , c, low
few cuttings, shell fragments, poorly sorted
114.00 - 115.00 Sand, green , c, moderate
poorly sorted
115.00 - 117.00 Sand, green , m, moderate
117.00 - 118.00 Sand, green , m, moderate
moderately sorted
118.00 - 119.00 Sand, light green , m-c , moderate-low
119.00 - 120.00 Sand, light green , m-c , moderate-low
poorly sorted
120.00 - 121.00 Sand, grey-green , m-c, low
few cuttings
121.00 - 122.00 Sand, grey , c, low
few cuttings
122.00 - 124.00 Sand, grey , c, low
124.00 - 126.00 Sand, grey , m-c, low-very low
few cuttings
126.0 Sand, grey-green , m, moderate
few shell fragments
126.00 - 128.00 Sand, grey , m, low-very low
few cuttings
128.00 - 130.00 Sand, grey , m-c, very low-traces
few cuttings, badly sorted, shell fragments
130.00 - 132.00 Sand, grey , m-c, very low-traces
134.00 - 136.00 Sand, dark green , f, high-very high
136.00 - 139.00 Sand, grey-green , m-c, low to moderate
few cuttings, badly sorted
139.00 - 141.00 Sand, grey , m-c, low-very low
few cuttings, some shell fragments
141.00 - 143.00 Sand, grey , m-c, very low
few cuttings
143.00 - 145.00 Sand, grey , m, very low
few cuttings
145.00 Sand, dark green-black , f, very high
some shell fragments
145.00 - 302.00 core description P. Laga - see below
302.00 - 305.00 Silt, grey , very low
grey clay cuttings
305.00 - 308.00 Silt, grey, traces
light grey clay cuttings
308.00 - 311.00 Silt, green/grey, traces
light grey silty clay cuttings, shell fragments
311.00 - 314.00 Silt, green/grey, traces
light grey silty clay cuttings
314.00 - 317.00 Silt, green/grey, traces
light grey silty clay cuttings/some samples less clayey and a bit more sandy
317.00 - 323.00 Sand, green/grey , f-m, low
clayey
323.00 - 326.00 Sand, green/grey , vf, low
shell fragments,clayey
326.00 - 329.00 Sand, green/grey , vf, very low-low
shell fragments,clayey, few grey clay cuttings
329.00 - 333.00 Sand, green/grey , vf, very low-low
clayey, very few small grey clay cuttings
333.00 - 336.00 Sand, green/grey , vf, low
clayey, very few grey clay cuttings
336.00 - 343.00 Sand , green/grey , vf, low
clayey, few grey clay cuttings
343.00 - 346.00 Sand , green/grey , vf , low
clayey, very few grey clay cuttings
346.00 - 349.00 Sand, green/grey , vf, low
clayey, few grey clay cuttings
349.00 - 352.00 Sand, green/grey , vf, low
clayey, few grey clay cuttings
352.00 - 355.00 Clay, grey, very low
sand particles, grey clay cuttings
355.00 - 358.00 Clay , light grey, traces
with light grey clay cuttings
358.00 - 362.00 Clay , light grey, traces
with light grey clay cuttings, shell fragments
362.00 - 366.00 Clay , grey, traces
with grey clay cuttings
366.00 - 368.00 Clay , grey, traces
with grey clay cuttings
368.00 - 372.00 Clay , grey, traces
with grey clay cuttings,
372.00 - 375.00 Clay , grey, traces
with grey clay cutting
375.00 - 378.00 Clay , grey, traces
with grey clay cuttings
378.00 - 381.00 Clay , grey , traces
with grey clay cuttings, very few sand particles
381.00 - 384.00 Clay , grey , traces
with grey clay cuttings, very few sand particles
384.00 - 387.00 Clay , grey , traces
with grey clay cuttings, silty clay
387.00 - 390.00 Clay , grey , traces
with big grey clay cuttings, silty clay
390.00 - 394.00 Clay , grey , traces
with grey clay cuttings, silty clay
394.00 - 397.00 Clay, grey, traces
with very few grey clay cuttings, silty clay, few cuttings
397.00 - 400.00 Clay, grey, traces
grey clay cuttings
400.00 - 403.00 Clay, grey, traces
small grey clay cuttings, silty material in between
403.00 - 406.00 Clay, grey, traces
grey clay cuttings
406.00 - 410.00 Clay, grey, very low-low
grey clay cuttings, sandy particles, shell fragments
410.00 - 413.00 Clay, grey, very low-low
few cuttings, sand particles
413.00 - 416.00 Clay, grey, very low-low
few cuttings, shell fragments, sand particles
416.00 - 419.00 Sand, grey, n/a, traces-low
abundant nummulites (1-2 mm) and shell fragments, few clay cuttings
419.00 - 422.00 Sand, grey , n/a , traces-low
abundant nummulites (1-2 mm) and shell fragments, very few clay cuttings
422.00 - 425.00 Sand, grey , f-m, traces
shell fragments (<1 mm), probably nummulites
425.00 - 428.00 Sand, grey , n/a , traces
shell fragments, nummulites (1-2 mm), sandstone fragments
428.00 - 431.00 Sand, grey , f , traces
shell fragments, nummulites (1-3 mm)
431.00 - 434.00 Sand, grey , f, traces
shell fragments, nummulites (1-3 mm), sandstone fragments
434.00 - 437.00 Sand, grey , n/a, traces
shell fragments, nummulites (1-5 mm), sandstone fragments
437.00 - 440.00 Sand, grey , n/a, traces
shell fragments, nummulites (1-3 mm), sandstone fragments, few cuttings
440.00 - 443.00 Sand, grey , n/a, traces
shell fragments, nummulites (1-3 mm), few cuttings
443.00 - 446.00 Sand, grey , f, traces
shell fragments, few cuttings
446.00 - 448.00 Sand, grey , f, traces
shell fragments
448.00 - 452.00 Sand, grey , vf-f, traces
shell fragments
452.00 - 455.00 Sand, grey , n/a, traces
large nummulites (5 mm), stone fragments, shell fragments
455.00 - 457.50 Sand, grey , vf-f, traces
large nummulites (5 mm), stone fragments, shell fragments
458.00 - 461.00 no cuttings recovered
461.00 - 464.00 Sand, grey , vf, traces
clayey
464.00 - 467.00 Sand, grey , vf, traces
shell fragments, stone fragments, small nummulites (1 mm)
467.00 - 470.00 Sand, grey , f, traces
shell fragments, small nummulites (<1 mm)
470.00- 473.00 Sand, grey , f, traces
few shell fragments, silty, stone fragments
473.00 - 476.00 Sand, grey , f, traces
476.0 Silt, grey, traces
clay cuttings
476.00 - 479.00 Silt, grey, traces
clayey, dried out
479.00 - 482.00 Silt,grey, very low
clay cuttings, sand particles
482.00 - 485.00 Silt, grey, very low
clayey, silty
485.00 - 488.00 Silt, grey, very low
almost no cuttings
488.00 - 491.00 Sand, grey, vf, traces
dried out, shell fragments
491.00 - 494.00 Silt, grey, traces
clay cuttings and mm scale stone fragments
494.00 - 497.00 Silt, grey, traces
clay cuttings
497.00 - 500.00 Clay, grey, traces
clay cuttings, stone fragments
500.00 - 503.00 Clay, grey, traces
clay cuttings, stone fragments
503.00 - 50500 Clay, grey , traces
clay cuttings
505.00 - 508.55 Clay, green/grey, traces
clay cuttings
Description of the core samples - P. Laga
core Nr. * drilled from - to (in m) * (length of the described core)
01. 145.00 - 146.04 (L: 74 cm - 10 cm laboratory sample 145.52 - 145.62 m)
(two core pieces: 145.00 - 145.52 and 145.62 - 145.94)
Dark-green, nearly black fine to medium very glauconitic sand, some pale tracks with a rim of concentrated dark glauconite; no chalk
02. 146.04 - 147.00 (L: 45 cm)
(only 45 cm undisturbed core)
146.00 - 146.20 disturbed core: only washed out shell remains with fine gravel.
146.20 - 146.65 black to dark-green fine to medium, very glauconitic sand, some whitish tracks between 24-41 cm; no chalk
03. 147.00 - 147.90 (L: 17 cm - 10 cm lab sample 147.77 - 147.87 m)
(17 cm undisturbed; 60 cm of the core is filled up with washed out shell remains and gravel)
60 - 77 cm: same dark glauconitic sand, no shells, no chalk
04. 147.90 - 148.81(no core recovery)
05. 148.81 - 149.59 (L: 43 cm)
(only shell remains, = rubbish from 149.09 to 149.52 m)
06. 149.59 - 150.63 (L: 49 cm (37+12 cm) - 8 cm lab sample)
(at the top : 36 cm washed out shell remains and fine gravel)
00.00 - 37.00 cm same black sand, homogeneous, no shells
37.00 - 45.00 cm (= 8 cm lab sample)
45.00 - 57.00 cm lighter dark-green fine clayey sand, no shells; no chalk
07. 150.63 - 151.72(no core recovery)
08. 151.72 - 152.81 (L: 65 cm - 10 cm lab sample)
00.00 - 36.00 only washed out shell remains and gravel
36.00 - 65.00 black sand with shell remains in the upper most 7 cm; sand is probably disturbed (no sediment design at all and at the border of the core: green fine clayey sand)
09. 152.81 - 153.59 (L: 71 cm - 20 cm lab sample 153.36 - 153.56 m)
00.00 - 10.00 same black glauconitic sand, no sediment design
10.00 - 51.00 mixture of shell remains, gravel and coarse sand (completely unreliable core zone)
51.00 - 58.00 lighter green glauconitic fine sand with visible stratification; no chalk
58.00 - 64.00 several bone fragments (up to 3 cm long) in same green sand
64.00 - 68.00 core partially with dark brown sandy and micaceous clay
The other part of the core up to the end (71 cm) is filled up with the same green glaunitic sand (probably not at place?)
10. 153.59 - 155.09 (L: 64 cm - 20 cm lab sample 154.86 - 155.06 m)
00.00 - 04.00 rubbish = shell remains and a pyrite concretion (3 cm long)
04.00 - 55.00 dark brown-grey very sandy clay or clayey sand, micaceous, from 30 cm to 40 cm: transition from brown coloured clay to green grey sand; from 40-55 cm: grey-green clayey sand, finely mottled with whitish spots; still calcareous
55.00 - 60.00 flushed in shell debris and coarse sand
60.00 - 64.00 grey sandy clay, with several black spots (probably pyrite); still calcareous
11. 155.09 - 156.12 (L: 78 cm - 10 cm lab sample 155.95 - 156.05 m)
(53 cm rubbish, shell remains)
53.00 - 61.00 dark-brown sandy micaceous clay, intensively biodisturbed, some black spots (pyrite?); calcareous
61.00 - 78.00 gradually lighter coloured, more sandy and less clayey; distinct presence of broken up thin clay laminae with 2 distinct tracks at 70.5 and 75.5 cm with a dark rim; less to not calcareous at the base
12. 156.12 - 157.12 (L: 65+20 cm - 20 cm lab sample 156.89 - 157.09 m)
00.00 - 12.00 clay and parafine filling
12.00 - 24.00 disturbed clay with washed out shell remains
24.00 - 34.00 grey-green finely biodisturbed clayey sand, no chalk
34.00 - 47.00 dark grey-greenish sandy clay, many broken up clay laminae by biodisturbance + black pyritic spots
47.00 - 65.00 dark grey-brownish clay with many fine silt and fine sand, spots (intensively biodisturbed), micaceous; black spots - amorph pyrite; no chalk
13. 157.12 - 158.12 (L: 81+10 cm - 10 cm lab sample 157.92 - 158.02 m)
00.00 - 10.00 light grey-green very fine silty micaceous and calcareous sand
10.00 - 53.00 upper limit irregular, perforated, darker sandy clay with tracks and many black pyritic spots with highest concentration of black spots between 25-37 cm; calcareous
53.00 - 64.00 gradually more sandy clay, big pyrite concretion at 58 cm (Ø 2 cm)
64.00 - 81.00 gradually less clayey, many light coloured spots (biodisturbance); still some pyitic spots, still calcareous, more fine light-grey sand at the bottom of the core
14. 158.12 - 159.12 (L: 88 cm - 10+8 cm lab samples)
(bottom of the core: 158.94 m)
00.00 - 05.00 rubbish (disturbed clay with shell remains)
05.00 - 30.00 dark brown-grey silty and sandy clay, many black pyritic spots, calcareous
30.00 - 55.00 same clay, but with fine whitish sand spots and only a few black pyritic spots
55.00 - 67.00 lighter more sandy brown clay with larger sand zones and layer (a 3 cm thick oblique light grey sand layer from 63 to 66 cm); calcareous
67.00 - 74.00 darker less, sandy clay, one smaller sand spot at 72 cm
74.00 - 88.00 a darker grey-brown clay layer, sand content is diminishing, more and more a heavy silty clay (many fine silt spots by biodisturbance); still calcareous
15. 159.12 - 160.12 (L: 17+70 cm - 10+8 cm lab samples 159.21-159.39 m)
upper core:
00.00 - 17.00 (= 159.12-159.39) 10 cm dark-grey heavy clay with many silt spots - calcareous, 7 cm more sandy clay
lower core: (= 159.39 - 160.09 = 70 cm)
00.00 - 20.00 clayey sand, many whitish sand spots, between 5-10 cm, intensively perforated clay layers and a black pyritic spot
20.00 - 45.00 grey clay, only very small sand spots, many are black pyritic between 20-40 cm.
45.00 - 70.00 gradually less sandy, the last 10 cm: a heavy dark clay with fine silt spots
16. 160.12 - 161.12 (L: 83 cm + 18 cm lab sample)
00.00 - 14.00 same heavy grey clay, silty and with very small black pyritic points.
14.00 - 30.00 sudden change of colour: from grey to dark-grey (organic material?) more pure clay layers and laminae, but broken up by biodisturbance; from 20 cm on: more sandy.
30.00 - 43.00 the broken up clay laminae are less distinct, more mixed with sand laminae, very micaceous, more and more sand spots
43.00 - 69.00 grey-greenish sandy clay, many whitish sand spots, very intensively biodisturbed - remains of a clay layer at 50 cm
69.00 - 78.00 sand content is diminishing down, some pyritic sand spots
78.00 - 83.00 more and more heavy silty clay, many but very small black pyritic points at 80-81cm; very calcareous
17. 161.12 - 162.12 (L: 103 cm/100 cm drilled)
00.00 - 45.00 grey silty clay, many very fine silt spots, some black pyritic points, between 11-13 cm: a whitish brownish calcareous concretion; very calcareous
45.00 - 54.00 alternation of 3 more sandy and 3 more clayey layers, 1 to 1.5 cm thick, 2 clayey layers are broken up by perforations, in the sandy layers, remains of numerous clay laminae
54.00 - 60.00 brown-grey sandy clay: fine clay and sand spots
60.00 - 85.00 sandy clay and even whitish sand layer from 70-88 cm but with heavy plastic very dark clay layer from 74.50-77 cm, below 80 cm, more homogeneous darker very sandy clay
85.00 - 90.00 sand content is diminishing
90.00 -100.00 a heavy clay with many silty spots, intensively biodisturbed; calcareous
18. 162.12 - 163.12 (L: 95 cm - 10 cm lab sample 162.99 - 163.09 m)
(95 cm = 162.12-163.07 ?!)
00.00 - 04.00 dark brown silty clay, slightly calcareous
04.00 - 07.00 very sandy layer, with many whitish mottles
07.00 - 24.00 brown nearly homogeneous clay, sandy with only black pyritic small spots; on 14.50 and 20 cm: some whitish larger sand spots
24.00 - 40.00 more whitish but smaller sand spots
40.00 - 60.00 still sandy clay, but small sand spots, some are pyritic
60.00 - 76.00 darker sandy clay, less sand spots, but a distinct sand joint at 72.50 cm
76.00 - 95.00 perforated contact with a darker heavy clay, silty with broken up pure clay laminae; no chalk
19. 163.12 - 164.12 (L: 84 cm - 20 cm lab sample 163.90 - 164.10 m)
(84 cm = 163.12 - 163.96 (?) = swelling of the clay)
00.00 - 18.00 brown-grey slightly sandy and silty clay, sediment design only very fine silt points
18.00 - 51.00 brown-grey silty clay with numerous whitish sand spots, whitish sand spots with a maximum between 30-45 cm
51.00 - 65.00 nearly homogeneous sandy clay, only some black pyritic spots a larger sand track at 60 cm.
65.00 - 84.00 more and more silty clay, micaceous, only a few black sand spots, no chalk.
20. 164.12 - 165.12 (L: 87 cm - 20 cm lab sample 164.89 - 165.09 m)
00.00 - 15.00 a quite homogeneous silty and sandy clay, some black pyritic spots
15.00 - 35.00 more sandy clay, but also more traces of clay lenses and layers, many very fine whitish sand spots
35.00 - 77.00 more sandy clay
35.00 - 44.00: finely laminated whitish sand and clayey sand
44.00 - 52.00: more remains of clay laminae, at 44 cm a wood fragment
52.00 - 77.00: very sandy clay, with many whitish sand spots; slightly calcareous
77.00 - 87.00 more silty and less sandy clay with black pyritic spots; calcareous
21. 165.12 - 166.12 (L: 94 cm - 10 cm lab sample 165.97 - 166.07 m)
00.00 - 75.00 grey-green finely sandy and silty clay, whitish and black (pyritic) sand spots; more sandy at the top and a zone between 12-17 cm; a sandy layer at 66-67.50 cm; at 68-70 cm irregular shaped clay fragment with a darker rim, whitish dots at 57 cm - probably gypsum crystals; no chalk
75.00 - 94.00 more and more silty and less sandy clay
22. 166.12 - 167.12 (L: 85 cm - 20 cm lab sample 166.88 - 167.08 m)
00.00 - 35.00 very sandy clay, very micaceous, numerous white sand spots, some black pyritic one's, no chalk, irregular contact with heavy silty clay
35.00 - 65.00 grey-green heavy silty clay, less sandy
65.00 - 79.00 downwards gradually sandy
79.00 - 83.00 a very irregular sandy layer, lighter colour micaceous with an irregular lower boundary with a heavy darker grey silty clay
83.00 - 85.00 darker grey-green, silty clay, no chalk
23. 167.12 - 168.12 (L: 64.50 cm - 40 cm lab sample 167.68 - 168.08 m) (drilling length from 167.12 to 167.68 = 56 cm - core length = 64.50 cm)
A heavy silty and somewhat sandy clay, from 25-40 cm: a little bit more sandy and micaceous; between 45-56 cm: many broken up pure clay laminae with more silty clay in between; at the bottom: again more sandy; no chalk
24. 168.12 - 169.12 (L: 85 cm - 20 cm lab sample 168.87 - 169.07 m)
(drilling length from 168.12 to 169.87 = 75 cm - core length: 85 cm)
00.00 - 10.00 same heavy grey-green clay with some larger more sandy tracks
10.00 - 24.00 same heavy clay: many broken up pure clay laminae in a more silty clay
24.00 - 30.00 gradually more sandy and micaceous
30.00 - 40.00 darker (more organic material?) very sandy and micaceous, with a sandiest maximum at 34-36 cm
40.00 - 68.00 grey-green silty clay, gradually less sandy
68.00 - 85.00 a heavy darker grey-green clay with only smaller, silty spots or dots, some whitish dots at 72 cm (gypsum crystals); no chalk
25. 169.12 - 170.12 (L: 87.52 cm - 20 cm lab sample 169.89 - 170.09 m) (continuous unbroken core, drilled length 77 cm/core length: 87.50 cm)
00.00 - 09.00 grey-green sandy clay with a layer of darker grey very plastic clay with very small blackish pyritic spots
09.00 - 64.00 grey-green very sandy clay, with many whitish sand spots, micaceous; no chalk
from 35-42 cm: large black pyritic sand mottles
from 36 cm on: gradually more and more traces of intensively broken up dark clay laminae by biodisturbance
64.00 - 68.00 idem, more clayey and less sandy, at 65 cm a larger track (Ø 1.5 cm) filled up with very sandy sediment
68.00 - 76.00 mainly dark grey plastic clay, with sand intercalations at 73 and 75.50 cm, also perforated by tracks at the top
76.00 - 87.50 nearly homogeneous, heavy silty clay with some black (pyritic) and whitish sand spots; no chalk
26. 170.12 - 171.12 (L: 86.50 cm - 20 cm lab sample 170.89 - 171.09 m)
(continuous unbroken core sample, drilled length: 77 cm/core 86.50 cm)
00.00 - 49.00 lighter grey-green, very sandy clay, many whitish sand spots
* from 08.00 - 25.00: traces of grey plastic clay laminae, completely disturbed by biological activities (= biodisturbance)
* idem from 40-49 cm
* from 32-40 cm sand maximum
49.00 - 70.00 heavy silty and sandy clay; on top a perforated contact, many black pyritic sandy spots
70.00 - 87.50 very heavy grey-green clay with many very small silty spots, but there are still fine sand grains.
No chalk in the whole core
27. 171.12 - 172.12 ( L: 82 cm + 18 cm lab. sample 171.88 - 172.06 m) (drilled length 76 cm/core 82 cm; from 0-60 cm: core broken up in 9 main fragments)
00.00 - 43.00 green pure wax-like heavy clay, only very small silt dots, some traces of shells; calcareous
43.00 - 60.00 same clay, but gradually with a higher sand fraction, calcareous; at 60 cm a large (6 cm long) pyrite concretion
60.00 - 82.00 darker grey-green very sandy clay with between 65-75 cm many traces of broken up laminae of grey plastic clay; calcareous between 60-68 cm: many pyritic black spots
28. 172.12 - 173.12 (L: 86 cm - 20 cm core sample 172.89 - 173.09 m) (drilled length: 77 cm - core 86 cm + a completely intact undisturbed core)
On top: 2 to 3 cm heavy green silty clay (oblique boundary)
03.00 - 04.50 sand lens or perforation
04.50 - 26.00 grey-green heavy clay with small sand and silt spots, with larger perforation, filled up with more sandy sediment (very distinct at 25 cm)
26.00 - 86.00 grey-green heavy clay, gradually less sandy and silty; at 39 cm last larger sand lens; from 65 cm: nearly homogeneous grey-green clay with only very small silty dots
29. 173.12 - 174.12 (L: 85 cm - 18 cm lab samples 173.88 - 174.06 m)
(drilled length: 77 cm - core length: 85 cm)
00.00 - 07.00 darker green silty clay, very heavy; calcareous
07.00 - 38.00 lighter grey-brownish wax-like very heavy clay, very calcareous; at 10 cm an oblique layer, 1 cm thick of the former darker green clay; some silty & pyritic points
38.00 - 55.00 same wax-like clay, but somewhat darker and greenish; at 52 cm a concentration of very fine whitish silt dots
55.00 - 85.00 same heavy clay, but with a higher sand content, at 72 cm: black pyritic sand spots; very calcareous
30. 174.12 - 175.12 (L: 83.50 cm - 20 cm lab sample 174.89 - 175.09 m)
00.00 - 22.00 grey-green brownish sandy clay, traces of clay laminae of grey plastic clay micaceous no chalk, black sandy pyritic spots at 6 and 16 cm
22.00 - 44.00 grey heavy clay with fine silty points, at the top intensively perforated by tracks, very larger tracks (up tot 3 cm wide) at 38 and 42 cm
44.00 - 53.00 same plastic clay, only a few sandy tracks at 45 cm (Ø 1.5 cm) and at 48 cm a more sandy zone
53.00 - 83.50 a green grey wax-like heavy clay, only fine silty spots and some traces of shells at 56 and 74 cm; a last sandy track at 62 cm; at 70 and 75 cm: irregularly shaped lenses of same darker clay, clay is calcareous
31. 175.12 - 176.12 (L: 84.50 cm - 20 cm lab sample 175.88 - 176.08 m)
Grey-green paler heavy wax-like clay with only fine silt and black sand spots, very calcareous; from 75 cm gradually a higher sand and silt content, also very calcareous, with many very fine whitish spots of paler pure clay; between 30-38 cm a strange irregularly shaped darker lens; traces of shells at 43 cm
32. 176.12 - 177.12 (L: 95 cm - 10 cm lab sample 176.99 - 177.09 m)
At the top some wax-like grey-green clay, very homogeneous, only a very few indistinct silt dots.
10.00 - 35.00 gradually higher sand content; at 15 cm a larger black pyritic sand mottle and at 28 cm a concentration of fine black sand spots
35.00 - 53.50 a quite homogeneous sandy clay, micaceous with only some black pyritic spots shell traces at 38.50 cm; between 46-53 cm a very strange irregular figure with a black pyritic border (a track?)
at 53.50 a very sharp but slightly curved limit with a much darker sandy clay (higher content of organic material), also very micaceous and still with fine whitish spots; poorly calcareous
53.50 - 80.00 the darker colour is diminishing downwards
* at 69 cm a pale whitish track with shell-traces inside
* at 76 and 81 cm: black pyritic sandy spots.
80.00 - 95.00 a less sandy, more silty brownish grey heavy clay with fine mica and black pyritic spots; no chalk
33. 177.12 - 178.12 (L: 85 cm - 20 cm lab sample 177.89 - 178,09 m)
00.00 - 33.00 brown-grey heavy silty clay with fine sand grains, calcareous, sandy tracks between 4-9 cm, from 20 cm downwards to 33 cm more sandy and micaceous, some dispersed black pyritic sand spots; at 33 cm 2 larger black sand tracks
33.00 - 53.00 darker brown sandy clay, micaceous with some traces of intensively biodisturbed clay layers; between 39-50 cm: numerous black pyritic spots and a larger blackist track at 46 and 49 cm, lower limit in sharp with a paler brown less sandy clay
53.00 - 78.85 at 54 and 55 cm: sandy tracks; at 58 cm: a pyrite concretion; the clay becomes downwards paler and less sandy; many fine black pyritic spots; clearly perforated between 72-78.5 cm; calcareous
78.85 - 85.00 again darker brown very sandy sediment; no chalk
34. 178.12 - 179.12 (L: 95 cm - 10 cm lab sample 178.99 - 179.09 m)
00.00 - 43.00 brown silty heavy clay at the top, from 8 cm increasing sand content, from 25 cm a sandy clay till 43 cm, at the bottom a perforated clay layer, shell traces at 18 and 29 cm
43.00 - 68.00 dark brown clayey sand with remains of clay lenses and laminae, micaceous and many black pyritic mottles
68.00 - 86.00 dark brown sandy clay intensively biodisturbed with many fine silty and sandy spots, whitish, sand blackish; at 83 and 85 cm: sand layers; poorly calcareous
86.00 - 95.00 a dark brown wax-like heavy clay with only silty spots, no chalk
35. 179.12 - 180.12 (L: 86.50 cm - 20 cm lab sample 179.87 - 180.07 m)
00.00 - 22.00 brown silty heavy clay with increasing sand content downwards and several larger perforations at the bottom; no chalk, but traces of shells at 7,5 and 10.50 cm
22.00 - 44.00 dark-brown, sandy clay to clayey sand, mica rich, many black sandy tracks and remains of clay lenses or layers
44.00 - 47.00 blackish disturbed zone filled up with pyrite concretions, shell debris, and black organic material, wood fragments and light grey-greenish sand
47.00 - 51.00 paler greenish brown sand with some perforations; no chalk
51.00 - 62.00 brown clayey sand, mica rich
62.00 - 86.50 darker brown sandy clay with decreasing sand content and increasing clay and silt content, many fine black pyritic spots; no chalk
36. 180.12 - 181.12 (L: 90 cm - 18 cm lab sample 180.90 - 181.08 m)
00.00 - 50.00 brown sandy nearly homogeneous heavy clay, some very fine pyritic and sandy spots, downwards sand content is increasing; no chalk
50.00 - 90.00 more and more heavy silty clay - a very fine indistinct sediment design of pale silt point and darker clay spots, some shell fragments (debris) at 87 cm; no chalk
37. 181.12 - 182.12 (L: 86 cm - 20 cm lab sample 181.89 - 182.09 m)
(one continuous core)
Brown heavy silty wax-like nearly homogeneous clay with very little sediment design and few black pyritic spots; from 20 cm sand content is increasing downwards; from 65 cm clay is micaceous; from 70 cm on a sandy clay with more black pyritic spots; scattered shell debris
38. 182.12 - 183.12 (L: 85.50 cm - 20 cm lab sample 182.89 - 183.09 m)
(continuous core, broken at 36 cm)
00.00 - 08.00 brown clayey sand, even finely laminated, with some broken up clay laminae
08.00 - 37.00 downwards increasing sand content becoming sandy clay, intensively biodisturbed
37.00 - 85.50 gradual change from a sandy clay to a silty heavy clay, with very little sediment design at the bottom (only very fine silty spots); at 51.50 cm a 3 cm long oblique black pyritic sand lens; no chalk
39. 183.12 - 184.12 (L: 87 cm - 18 cm lab sample 183.86 - 184.04 m)
(complete intact core)
On top a light-brown silty heavy clay, homogeneous, only black pyritic spots downwards gradually increasing sand content, between 60-80 cm, remains of disturbed clay lenses; at 70 cm first light sand spot Ø 7 mm; black pyritic spots from 38-78 cm; from 80-87 cm a very sandy clay with several pale sand mottles; no chalk
40. 184.12 - 185.02 (L: 89 cm - 20 cm lab sample 184.79 - 184.99 m)
(complete continuous core)
Very homogeneous brown clay with very little variation in composition.
00.00 - 30.00 heavy silty clay (very fine silty points); no chalk
30.00 - 50.00 a heavy wax-like clay, much less silt dots; no chalk
50.00 - 80.00 some increasing sand content with maximum at 70 cm and decreasing again; calcareous
80.00 - 89.00 again a silty clay such as on top; clearly calcareous
41. 185.02 - 186.02 (L: 87 cm - 20 cm lab sample 185.78 - 185.98 m)
(complete core)
Brown very silty heavy clay, calcareous gradually somewhat sandy to the bottom of the core; very homogeneous, only dispersed fine black pyritic spots; from 60 to the bottom: more and more lighter brown silty indistinct spots, some white spots (gypsum?); pyrite concretions at 6, 26, 32 cm and a small one at 46 cm
42. 186.02 - 187.02 (L: 94,50 cm - 10 cm lab sample 186.87 - 186.97 m)
(complete core)
00.00 - 10.00 lighter-brown and more sandy silty clay with a rounded piece (5 cm long, 15 cm wide) of darker more plastic clay
10.00 - 50.00 same clay, gradually darker, less sandy very plastic clay with very little sediment design (same indistinct paler, very small silt spots
50.00 - 94.50 same clay but now gradually more silty and sandy; the lowest 10 cm is a lighter brown silty and slightly sandy clay with very fine remains of broken up darker clay laminae
at 57.50 cm: a small calcareous concretion
at 80.00 cm: a pyrite concretion
no chalk
43. 187.02 - 188.02 (L: 88.50 cm)
(complete intact core)
00.00 - 10.00 very dark brown silty and sandy clay, no chalk with very fine silty spots
10.00 - 71.00 brown silty heavy clay, many small black pyrite spots and larger darker brown spots (tracks Ø 20.5 cm) dispersed in the clay; at 46 cm: an oval spot (2.5 long, 1.5 cm wide); at 52 cm an elongated one 4 cm long and 7 mm wide; a concentration of similar spots between 60-70 cm; at 71 cm: a pyrite concretion
71.00 - 88.50 lighter brown silty and more sandy clay, some traces of more clayey laminae, some black pyrite spots; at the bottom a very sandy micaceous clay; no chalk
44. 188.02 - 189.02 (L: 97 cm - 10 cm lab sample 188.88 - 188.98 m)
(complete core)
00.00 - 23.00 brown sandy micaceous heavy silty clay; black pyritic and pale sandy spots, some traces of sandy laminae
23.00 - 65.00 darker brown, silty clay, dispersed small black pyritic spots, with a concretion between 38-48 cm
65.00 - 80.00 same heavy silty clay, with pieces of dark brown plastic clay (up to 2.5 cm long and 5 mm wide)
80.00 - 97.00 darker brown, heavy clay with very fine silt spots; a pyrite concretion at 81.50 cm, a smaller at 85 cm (a pyrite small track)
45. 189.02 - 190.02 (L: 93 cm - 10 cm lab sample 189.88 - 189.98 m)
(complete core - a hole of 3 cm by 1.5 cm at 77 cm: external mould of a concretion ?)
00.00 - 20.00 dark-grey silty clay, fine spots of darker clay and many lighter very fine silt spots; at 7 cm a larger pyrite concretion, 4 cm long and 2 cm wide
20.00 - 50.00 more and more brown, sandy and micaceous clay
50.00 - 80.00 more and more very sandy clay, very micaceous, to a clayey sand; very indistinct darker clayey mottles and lighter sand mottles; calcareous
80.00 - 93.00 a darker silty compact clay, very calcareous; in the brown silty clay occurrence of some darker clay spots (broken up clay laminae)
46. 190.02 - 191.02 (L: 89.5 cm - 10 cm lab sample)
(complete core, broken between 50-60 cm)
00.00 - 05.00 brown-grey compact silty clay, many silt spots
05.00 - 44.00 grey-brownish compact clay, few silt spots
44.00 - 49.00 idem, calcareous, at 49 cm traces of a septaria (calcareous concretion)
49.00 - 70.00 darker grey very heavy plastic clay, very few silt spots, a horizontal distinct silty layer at 67 cm with a sharp clear boundary at the top
70.00 - 89.50 dark grey nearly wax-like but still silty heavy clay, very little sediment design (some very fine indistinct silty spots); a pyrite concretion at 72 cm and a larger spherical pyritic concretion at 83 cm; traces of shells at 85 cm
47. 191.02 - 192.02 (L: 89 cm - 20 cm lab sample 191.79 - 191.99 m)
(complete intact core)
00.00 - 15.00 dark-grey compact heavy but silty clay
15.00 - 38.00 grey-brownish more and more silty and sandy clay, nearly no sediment design, only a few white spots (gypsum)
38.00 - 60.00 light-brown very sandy and micaceous clay, bright sandy spots and same darker clayey spots, very biodisturbed
60.00 - 89.00 gradually a less sandy and a more silty clay, also finely mottled by bright more silty and darker indistinct clay spots; no chalk
48. 192.02 - 193.02 (L: 86.5 cm - 20 cm lab sample 192.78 - 192.98 m)
(complete core)
Grey-brownish compact clay; very silty up to 45 cm; a large pyrite concretion (4.5 by 3 cm); from 45 cm darker grey-brownish, gradually less silty; at the bottom a dark-grey nearly wax-like plastic clay, but still with very fine silty spots); at 53 cm a concentration of very fine calcareous spots (fine tracks with calcareous concretions)
49. 193.02. - 194.02 (L: 66 cm - 40 cm geomechanical lab sample 193.57 - 193.97 m) (complete intact core)
00.00 - 20.00 same dark grey nearly wax-like silty clay; very little sediment design, pyrite concretion at 2 and 14 cm; some white spots (gypsum)
20.00 - 45.00 more and more silty and a little bit sandy heavy clay, pyrite concretion at 38 cm
45.00 - 66.00 more and more silty and sandy, micaceous clay, small dark spots of broken up clay laminae; no chalk
50. 194.02 - 195.02 (L: 83 cm - 20 cm lab sample 194.76 - 194.96 m)
(completely intact core)
Brown-grey very silty clay, many very fine light and dark indistinct spots, only a few black pyritic sandy spots; intensively biodisturbed; a smaller pyrite concretion at 77.50 cm, many very small pyrite concretions, no chalk; the colour is grey-brown at the top and changes gradually to brown at the bottom
51. 195.02 - 196.02 m (L: 85 cm - 18 cm lab samples 195.79 - 195.97 m)
00.00 - 20.00 a dark-grey homogeneous heavy wax-like clay, a little bit silty and traces of sand grains; pyrite concretions at 9.5 cm, 16 and 19 cm.
20.00 - 60.00 same compact clay, but distinctly more silty and more very fine silty sediment design
60.00 - 85.00 same compact clay, but more and more sandy, brown, larger pyrite concretion at 61 cm and a small one at 67 cm
no chalk
52. 196.02 - 197.02 (L: 81.50 cm - 19 cm lab samples 196.77 - 196.96 m)
(completely intact core)
Grey-brownish compact silty clay with a small amount of sand grains; only very fine silty dots as sediment design, some dispersed white spots (gypsum); several smaller pyrite concretions, larger ones at 6.9 and 28 cm
53. 197.02 - 198.02 (L: 74 cm - 20 cm lab sample 197.90 - 198.10 m)
(complete core)
00.00 - 09.00 dark-brown, compact clay; at the top a light-brown sand lens (24 cm - 4 mm high); pyrite concretion at 5.5 cm
09.00 - 74.00 brown compact silty clay, with an amount of sand grains a sediment design of very fine clear silt spots and some darker clay spots, a pyrite concretion (Ø 2,5 cm) at 35 and 71 cm; at 43.50 cm shell debris; at the bottom (from 60-74 cm) again more grey-brownish
54. 198.02 - 199.02 (no core recovery)
55. 199.02 - 199.91 (L: 78.50 cm - 18 cm lab sample 199.69 - 199.87 m)
(complete core)
Grey-brown homogeneous silty clay with some sand grains; no chalk
00.00 - 20.00 many silt spots
20.00 - 40.00 less silt spots
40.00 - 78.50 nearly without sediment design, plastic nearly wax-like clay
56. 199.91 - 200.91 (L: 80 cm - 20 cm lab sample 200.63 - 200.83 m)
(complete core)
00.00 - 20.00 grey-brownish compact silty clay, with some small silty spots at 16-17 cm; no chalk
20.00 - 30.00 grey compact silty clay, very homogeneous: some white spots (gypsum)
30.00 - 65.00 grey-greenish compact wax-like clay, a pyrite concentration (Ø 3 cm) at 43 cm
65.00 - 80.00 grey-green same compact clay, more silty but still wax-like, no chalk
57. 200.91 - 201.91 (L: 65,50 cm - 40 cm lab sample 201.51 - 201.91 m)
(complete core)
grey-brownish compact silty heavy clay, a little bit sandy
from 45 to 65.50 cm less silty and nearly without sand grains; a calcareous tube, filled up with pyrite at 53 cm and a pyrite concretion at 62 cm; at 59 cm a shell with 2 valves
58. 201.91 - 202.91 (L: 85cm - 20 cm lab sample 202.66 - 202.86 m)
(complete unbroken core)
Brown compact very silty clay, micaceous with some sand grains, the sediment design consists of very fine pale silty spots and dark brown clay spots (remains of broken up clay laminae) in various concentrations; higher concentration of clay laminae fragments between 55-70 cm; between 50-60 cm concentration of fine silty biodisturbance (many silty very small spots and tracks)
59. 202.91 - 203.91 (L: 86.5 cm - 20 cm lab sample 203.68 - 203.88 m)
(intact core)
00.00 - 40.00 brown very sandy micaceous silty clay with many black pyritic sandy spots, a few large ones at 15-20 cm and a lot of very small ones, pyrite concretion at 16 and 24 cm
40.00 - 50.00 gradually less sandy and silty and changing colour to grey-brownish
50.00 - 65.00 quite homogeneous silty clay with some whitish very small fine silty spots
65.00 - 75.00 dark grey very homogeneous, wax-like plastic clay, nearly without sediment design
75.00 - 86.50 idem, again more silty and lighter grey-brownish
60. 203.91 - 204.91 (L: 86 cm - 18 cm lab samples 204.70 - 204.88 m)
(intact core)
00.00 - 20.00 dark grey very plastic compact clay with only a few sand grains
20.00 - 45.00 gradually grey-brown silty clay and more sandy and micaceous clay, same sediment design, broken up clay laminae
45.00 - 65.00 gradually again grey-brownish less sandy and silty clay, with still fragments of clay laminae, a spot of whitish clay at 64 cm
65.00 - 86.50 darker grey wax-like plastic compact clay with very little sediment design: some broken up pale silty layers; scarcely calcareous
61. 204.91 - 205.91 (L: 85.5 cm - 20 cm lab sample 205.68 - 205.88 m)
(intact core)
grey-greenish compact heavy wax-like clay, very little sediment design (a little bit silty spots); pyrite concretions at 20 and 84 cm, darkest zone around 70 cm; poorly calcareous.
62. 205.91 - 206.91 (L: 86 cm - 20 cm lab sample 206.68 - 206.88 m)
(intact core)
00.00 - 13.00 brown sandy, micaceous, silty clay, no chalk
13.00 - 35.00 brown gradually changing to darker grey silty and sandy clay, little clay design, only some indistinct pale silty spots and black pyritic sand spots
35.00 - 60.00 idem, still sandy
60.00 - 86.00 grey silty clay; no chalk
63. 206.91 - 207.91 (L: 85 cm - 20 cm lab sample 207.65 - 207.85 m)
(continuous core, on top 5 cm are broken)
00.00 - 25.00 Brown-grey sandy and micaceous silty clay; many dark grey broken up very fine clay laminae in a lighter brown silty clay mass, pyrite on 18 and 33 cm
25.00 - 50.00 gradually changing colour to grey, less silty clay, some bigger lighter coloured more silty mottles at 49 cm
50.00 - 65.00 darker grey very homogeneous wax-like clay nearly without sediment design
65.00 - 85.00 gradually more silty clay, with lighter grey colour, more sediment design (fine silt spots, more biodisturbance); at 75 cm trace of shell fragment; pyrite at 75, 76, 79 and 80 cm
64. 207.91 - 208.91 (L: 81.50 cm - 18 cm lab sample 208.67 - 208.85 m)
(continuous core)
00.00 - 30.00 grey-brown sandy and silty, micaceous compact clay, no chalk; at 11 cm a continuous 2 mm thick dark-grey clay layer, covered by a silty lighter grey clay layer; much sediment design: brighter silty spots and darker clay spots (fragments of clay laminae)
30.00 - 55.00 Brown-grey to grey less sandy silty clay, quite homogeneous (only very fine, black pyritic spots); pyrite at 41 cm
55.00 - 81.50 grey-greenish silty, heavy compact clay, some sand grains, very little sediment design, some white dots (gypsum); no chalk
65. 208.91 - 209.91
(core completely reserved for geomechanical tests)
66. 209.91 - 210.91 (L: 82.50 cm - 22 cm lab sample 210.66 - 210.88 m)
(continuous core)
Grey silty compact clay, a little sandy, only very indistinct sediment design (intensively biodisturbed), only a few white gypsum points, black pyrite points and a few silty spots
at 2-7 cm a large light-brown concretion, less calcareous (siderite?) Ø up to 6 cm, pyrite at 75 cm.
67. 210.91 - 211.91 (L: 85 cm)
00.00 - 20.00 dark grey-brown wax-like very homogeneous clay, pyrite at 8, 9 and 19 cm
20.00 - 50.00 gradually lighter grey, very silty and a little sandy clay, with clay design (broken up clay laminae and some light grey silty tracks); pyrite at 34 cm
50.00 - 85.00 gradually light-grey, diminishing traces of clay laminae to a light-grey sandy clay at the bottom; pyrite
68. 211.91 - 212.91 (L: 85 cm - 18 cm lab samples 212.67 - 212.85 m)
(continuous core, opening at 74 cm)
Grey silty, a little sandy and micaceous compact clay; light grey at top and bottom; gradually darker to 40-50 cm and further gradually lighter to the bottom, no chalk, a clear sediment design through intensive biodisturbance (fragments of clay laminae and small tracks of organism)
69. 212.91 - 213.91 (L: 102.50 cm)
(continuous core, broken from 78 cm to the bottom)
Dark grey silty and a little sandy compact heavy clay, very few sediment design; wax-like dark clay from 75-90 cm with pyrite concretion at 80 cm, very few variation: more silty from 0-20 cm and from 95-102.50 cm
70. 213.91 - 214.91 (L: 84.50 cm - 20 cm lab sample 214.68 - 214.88 m)
(continuous core)
Grey finely mottled compact silty clay, a little sandy and micaceous, intensively biodisturbed; light silty spots and darker clay spots (= broken up clay laminae)
71. 214.91 - 215.91 (L: 85.50 cm - 18 cm lab samples 215.69 - 219.87 m)
(first 25 cm of the core is broken in 8 fragments)
00.00 - 40.00 grey-green compact silty clay with black (pyritic) points
40.00 - 85.50 darker grey-green compact wax-like clay, no sediment design; small pyrite concentration at 57, 61, 69, 72 and 75 cm; no chalk
72. 215.91 - 216.91 (L: 83 cm - 20 cm lab sample 216.67 - 216.87 m)
(continuous core)
Grey-green compact silty and more sandy clay, micaceous, no chalk; sediment design: black points, very small fragments of clay laminae and small silty spots and some sand mottles, pyrite at 8, 29 and 33 cm; a sand lens at 74 cm
73. 216.91 - 217.91 (L: 83 cm - 20 cm lab sample 217,66 - 217.86 m)
(continuous core, first 8 cm completely broken up)
Grey-green compact wax-like clay, very fine sediment design: white gypsum spots and some silty points; from 0-50 cm some sand grains and from 48-83 cm more silty spots; pyrite at 74 cm, no chalk
74. 217.91 - 218.91 (L: 85 cm - 18 cm lab sample 218.68 - 218.86 m)
(continuous core but last 9 cm are completely fragmented)
Grey-green heavy compact silty clay with some sand grains, wax-like from 0-35 cm; sediment design: traces of silt layers and pure clay laminae; pyrite concretion at 7 cm; no chalk
75. 218.91 - 219.91
(complete core send to the geomechanical lab)
76. 219.91 - 220.91 (L: 63.50+21 cm - 16 cm lab samples 220.46 - 220.62 m)
(the lowest core is completely fragmented)
upper core: darker grey-green wax-like plastic compact clay, very little sediment design: only a few traces of silty layers or lenses between 10-30 cm; several white gypsum points between 55-60 cm; pyrite concretion at 17, 27 and 38 cm
lower core:
00 - 10 same very plastic wax-like clay
10 - 13 gradually pale yellow calcareous clay
13 - 21 calcareous concretion (septaria)
77. 220.91 - 221.91 (L: 38 cm + 48 cm - 20 cm lab sample 221.17 - 221.37 m)
(the lowest 15 cm of the lower core is fragmented and in the upper core also from 8-18 cm)
upper core:
00.00 - 05.00 pale-green compact wax-like clay - slightly calcareous.
05.00 - 38.00 gradually change over a few cm to a very dark brown compact wax-like but silty clay; no sediment design, only a few white gypsum points
lower core
00.00 - 43.00 grey-green very homogeneous wax-like but still silty clay, some rare silty spots; at 20-22 cm a lense-shaped curved mottle of dark-brown clay.
43.00 - 48.00 pale-green same clay (clay partly dried out); no chalk
78. 221.91 - 222.91 (L: 85.50 cm - 20 cm lab sample 222.67 - 222.87 m)
(continuous core, fragmented from 62-72 cm)
Dark grey-green to brown compact a little silty wax-like clay,
07.00 - 20.00 many small silty spots; very little sediment design;
20.00 - 67.00 only dispersed silty spots; at 24 cm a small (5 mm high) bivalve Nucula shell, filled up with pyrite; traces of a shell at 50.50 cm; pyrite at 58 cm.
67.00 - 85.50 more sandy and silty pale brown-greenish compact clay, much more sediment design: broken up clay laminae and a few pale silty spots; no chalk
79. 222.91 - 223.91 (L: 88.50 - 18 cm lab samples 223.69 - 223.87 m)
(continuous, fragmented at the top and the bottom)
Grey-green at the top gradually changing to darker grey-green-brown at the bottom, very compact wax-like clay nearly without sediment design: only from 8-26 cm several pale silty spots, below only dispersed white points; traces of a shell at 85 cm; no chalk
80. 223.91 - 224.91 (L: 84 cm - 20 cm lab sample 224.67 - 224.87 m)
(continuous core)
00.00 - 10.00 dark-brown compact pure wax-like clay, slightly silty
10.00 - 35.00 gradually changing colour to grey-green, compact more silty clay with sand grains; without any sediment design; pyrite at 13, 25 and 31 cm
35.00 - 84.00 grey-green same wax-like clay, but with increasing sediment design from top to bottom; very fine silt spots and darker fragments of clay laminae, all very indistinctly; pyrite at 83.50 cm
81. 224.91 - 225.73 (L: 51 + 30cm)
(a void of 16 cm between the upper and the lower core - pulled out?)
upper core:
00.00 - 39.00 darker grey-green compact wax-like clay, only a very few dispersed silty points; pyrite concretion at 31 cm
39.00 - 51.00 darker more brownish same wax-like clay, but with many pale points (= silt points + shell fragments); calcareous
lower core:
00.00 - 10.00 light brown clay with many pale yellow points and spots, from 5-10 cm: colour change to dark grey and decrease of the pale yellow points; calcareous (edge of a septaria?)
10.00 - 20.00 dark grey-green compact silty clay; some thin pyritic tracks
20.00 - 30.00 pale-green (dried out) heavy micaceous clay
82. 225.73 - 226.73 (L: 85 cm - 20 cm lab sample 226.47 - 226.67 m)
(continuous core, at the top divided over 12 cm)
00.00 - 57.00 dark grey-green compact wax-like clay, dispersed silt points; at 24-25 cm a more silty layer and a major silty track with small fragments of clay laminae; dispersed white points (shell traces?); pyrite at 50 and 53 cm; calcareous
57.00 - 85.00 gradually lighter grey-green, more silty clay with some more sand grains and more sediment design: silty spots, lenses and tracks; calcareous
83. 226.73 - 227.65
(core completely send to the geomechanical lab)
84. 227.65 - 228.65 (L: 86 cm - 20 cm lab samples 228.38 to 228.58 m)
(core seriously fragmented from 6-36 cm)
00.00 - 40.00 dark-brown compact wax-like clay, a little silty, only a few dispersed silty points; pyrite at 33 and 36 cm; no chalk
40.00 - 86.00 gradual change of the colour to grey-green; same compact wax-like clay but silty; no chalk
85. 228.65 - 229.65 (L: 89 cm - 18 cm lab sample 229.43 - 229.61 m)
(continuous core)
Grey-green compact wax-like heavy clay, homogeneous, no sediment design, slightly more silty at the top; from 60 to 71 cm: many tracks filled up with calcareous pale brownish material (probably septaria horizon n° 60); shell remains and pyrites at 14 cm; no chalk, except the biodisturbed zone 60-71 cm, below that zone: poorly calcareous
86. 229.65 - 230.65 (L: 87 cm - 20 cm lab sample 230.41 - 230.61 m)
(continuous core, broken at 6 cm)
00.00 - 40.00 dark-brown changing gradually to greenish compact wax-like clay, no sediment design, except a few dispersed white points; pyrite at 23 cm
40.00 - 87.00 grey-greenish compact clay, a little more silty from 65 cm, sediment design: traces of broken up clay laminae; pyrite at 49, 59 and 62 cm); no chalk; slickenslides on two sub-horizontal fracture planes that cross each other.
87. 230.65 - 231.65 (L: 75 cm - 28 cm lab sample 231.23 - 231.51 m)
(continuous core)
Grey-green fairly dark compact wax-like clay, no sediment design, only whitish points and a 3 mm thick more silty oblique layer at 22 - 23 cm; the darkest zone is between 40-50 cm; from 57-69 cm a yellow-brownish very calcareous zone with traces of shells, distinctly biodisturbed (round and oval dark clay fragments = filling up of tracks?), at the bottom, more track-like clay mottles.
88. 231.65 - 232.65 (L: 67+18 cm - 20 cm lab samples 232.20 - 232.40 m)
(1e core: continuous; 2e: last 10 cm fragmented)
upper core:
00.00 - 15.00 grey-green compact silty clay with a few sandy & micaceous zones (tracks or lenses)
15.00 - 67.00 gradually darker grey compact wax-like heavy pure clay, no sediment design
lower core: dark grey-brown very pure wax-like clay; at the bottom green clay (dried out); several pyrite concretion at 7 cm
89. 232.65 - 233.65 (L: 84 cm - 20 cm lab sample 233.41 - 233.61 m)
(0-19 cm fragmented, 19-84 cm continuous core)
00.00 - 13.00 dark-brown compact wax-like silty clay
13.00 - 19.00 pale brown-yellow; concretion with pyrite (septaria-horizon?); very calcareous
19.00 - 55.00 dark brown-greenish sandy and silty micaceous compact clay, intensive biodisturbance with traces of completely reworked clay laminae; pyrite at 22 and 27 cm
55.00 - 84.00 dark-grey nearly black-greenish compact silty wax-like clay, perforated by very fine biodisturbance at the top; nearly no sediment design: some rare white points; pyrite at 69, 72 and 75 cm
90. 233.65 - 234.65 (L: 88 cm - 18 cm lab samples 234.41 - 234.59 m)
(continuous core, except at the top: fragmented over 15 cm)
00.00 - 20.00 very dark grey-green compact wax-like clay, only a few silty points visible; pyrite at 18 cm
20.00 - 40.00 idem, but a little more sandy; pyrite at 34 and 36 cm
40.00 - 88.00 same dark silty wax-like clay with a few sand grains; pyrite at 49, 59, 70 and 84 cm
91. 234.65 - 235.65 (L: 85.50 cm - 20 cm lab sample 235.39 - 235.59 m)
(continuous core but at the top completely fragmented over 15 cm)
Very dark grey-brownish compact very pure wax-like clay, no sediment design, only a few white points; small pyrite concretions at 16, 22, 26, 30, 33, 42, 45, 51 cm; some dispersed traces of shells (a.o. at 79.5 cm); no chalk
92. 235.65 - 236.65 (L: 65 cm + 40 cm -> geomechanical lab)
(top of the core over 9 cm fragmented)
00.00 - 20.00 same dark grey-green compact wax-like clay with many small pyrite concretion
20.00 - 40.00 idem, more silty
40.00 - 50.00 idem silty and a little sandy; pyrite at 48.50 cm
50.00 - 65.00 idem, again silty and less sandy, strange sediment design between 50-56 cm, more silty mottles looking like tracks, even one with concentric rings; calcareous
93. 236.65 - 237.62 (L: 80 cm - 40 cm lab samples 237.36 - 237.56 m)
(core seriously fragmented from 0-42 cm, continuous from 42-80 cm)
00.00 - 42.00 dark brown-greenish compact wax-like clay, some sediment design: broken up clay laminae at 10 cm
42.00 - 80.00 more grey-green silty compact clay with some sand grains, no sediment design; dispersed pyrite concretions; a little calcareous at the bottom
94. 237.62 - 238.62 (L: 84 cm - 20 cm lab sample 238.33- 238.53 m)
(continuous core, first 5 cm are fragmented)
Grey-green compact wax-like clay, a little silty, very little sediment design; from 10-22 cm: a concentration of broken clay laminae; from 25-53 cm a little sand grains; pyrite at 13, 18, 33, 57 and 70 cm; no chalk
95. 238.62 - 239.62 (L: 88 cm - 20 cm lab sample 239.36 - 239.56 m)
(continuous core, at the top fragmented over 10 cm)
Grey-green compact wax-like silty clay up to 20 cm and from 70-88 cm, from 20-70 cm more silty and sandy with maximum at approx. 45 cm and beneath the inverse gradual change to pure clay
96. 239.62 -240.62
(core completely to geomechanical lab)
97. 240.62 - 241.62 (L: 85 cm - 20 cm lab sample 241.33 - 241.53 m)
(continuous core, at the top 5 cm fragmented)
00.00 - 20.00 grey-green compact wax-like clay, a little silty, 2 silty spots at 14.5 and 20.50 cm
20.00 - 55.00 idem, gradually more silty
55.00 - 85.00 idem, lighter colour, also more sandy, some black pyritic sandy spots and joints, pyrite at 84 cm
98. 241.62 - 242.62 (L: 85 cm - 20 cm lab sample 242.35 - 242.55 m)
(continuous core, only irregularly broken at 4 cm)
Grey-green very homogeneous compact wax-like clay, a little silty, no sediment design; small pyrites at 24, 30, 40, 65 and 83 cm); no chalk
99. 242.62 - 243.62 (L: 83 cm - 18 cm lab samples 243.35 -243.53 m)
(continuous core)
00.00- 40.00 light-grey silty compact clay, micaceous, a little sandy with a very indistinct sediment design: at 11 cm a dark broken up pure clay layer of a few mm and many indistinct "reworked" clay laminae by biodisturbance, some lighter silty spots
40.00 - 83.00 much darker grey compact wax-like pure clay, no sediment design, except very small silty points between 60-65 cm
100. 243.62 - 244.62 (L: 89 cm - 18 cm lab sample 244.39 - 244.57 m)
(4 cm completely fragmented on top - continuous core)
Grey-greenish compact wax-like heavy clay: silty, a little sandy between 20-40 cm, more silty spots from 70 to 89 cm, no chalk
101. 244.62 - 245.62 (L: 87 cm - 20 cm lab sample 245.35 - 245.55)
(continuous core, at the top 15 cm are fragmented)
00.00 - 20.00 grey-green compact wax-like heavy clay, a little silty; no chalk
20.00 - 55.00 idem, with many very small whitish silty points; calcareous
55.00 - 70.00 gradual colour change to light grey-brownish, gradually more sandy clay
70.00 - 87.00 grey-brownish compact silty clay with distinct sediment design: darker spots of broken up clay laminae, black pyritic spots and pyrite concretions at 74 and 79 cm; very calcareous (the fresh clay is still green)
102. 245.62 - 246.90 (L 36+50 cm - 20 cm lab sample 246.20 - 246.40)
(continuous core, but fragmented over 11 cm at the bottom of the lower core)
upper core:
00.00 - 36.00 dark grey-greenish compact very heavy wax-like clay; a few silty spots; slightly calcareous
lower core:
00.00 - 12.00 same grey-green wax-like clay
12.00 - 24.00 lighter grey compact heavy silty clay with sediment design: indistinct silt points and broken up clay laminae
24.00 - 30.00 idem, but sediment design is more distinct
30.00 - 33.00 breccia of angular fragments of darker pure clay
33.00 - 50.00 silty clay (many silt spots and points); calcareous
103. 246.90 - 247.90 no core
104. 247.90 - 248.91 core completely send to the geomechanical lab
105. 248.91 - 249.90 (L: 85 cm - 20 cm lab sample 249.67 - 249.87 m)
(continuous core, at the top fragmented over 9 cm)
00.00 - 38.00 light grey-greenish silty and sandy clay, finely micaceous, with fine bright silty spots and darker clay spots (broken up clay laminae), calcareous; pyrite at 14cm
38.00 - 55.00 idem, but with many very distinct broken up clay laminae
55.00 - 60.00 darker grey wax-like compact clay, with a shell at 56 cm
60.00 - 85.00 grey-green same wax-like clay, but more silty spots at 62 & 64 cm: a 3-4 mm thick silt layer; pyrite at 82 cm; calcareous
106. 249.90 - 250.91 (L: 22+63 cm - 10 cm lab sample 250.07 - 250.17 m)
(the top 6 cm are broken; from 59 to 98 cm completely fragmented core in pieces of 1-2 cm (= lowest 39 cm of the core)
upper core:
00.00 - 06.00 light grey-green silty very sandy micaceous clay; pyrite concretion of 3-4 cm Ø
06.00 - 22.00 light grey-green silty sandy and micaceous clay with a distinct sediment design ("linoleum"-like); lighter silty clay with many broken up and distorted (biodisturbance) clay laminae; small pyrite concentrations at 10.5, 15 and 18 cm
22.00 - 32.00 lab sample
Lower core
32.00 - 59.00 same silty clay but less sandy and nearly micaceous, pyrite concentration at 44 cm; a little calcareous
59.00 - 98.00 darker green, less silty clay, but still silty and a little sandy; calcareous; slickenslides
107. 250.91 - 251.91 (L: 87 cm - 20 cm lab samples 251.66 - 251.86 m)
(complete continuous core from 8 to 87 cm)
00.00 - 08.00 light grey-green very sandy, silty and micaceous clay with the same sediment design as on top of the core above; a large pyrite concretion; no chalk
08.00 - 20.00 darker green very compact wax-like clay without sediment design (only a very few silt points), calcareous
20.00 - 29.00 same clay, with very poor sediment design, but more and more silty
29.00 - 45.00 same silty clay but with very distinct pieces of broken clay laminae and at 34 cm even a 3 mm thick clay layer
45.00 - 60.00 green brown, silty clay becomes more and more sandy and micaceous, but with the same sediment design
60.00 - 73.00 grey-brownish sandy micaceous clay, but still with the same sediment design (remains of clay laminae at 72 cm), traces of a shell
73.00 - 87.00 same clay with distinct sediment design, but much less sandy; at 80 cm a larger black (pyritic) sand spot (1,5 long and 1 cm wide); calcareous
Remark: the pyrite concretion on top of the core 107 fits nicely and are pieces of the same concretion
108. 251.91 - 252.90 (L: 86.50 cm - 20 cm lab sample 252.60 - 252.80 m)
(complete and continuous core, but the upper 9 cm are fragmented)
same grey-green silty clay, with distinct sediment design: darker pieces of clay laminae
00.00 - 06.00 light-green silty clay, calcareous
06.00 - 25.00 darker green compact clay, but still with many silty spots; at 25 cm very fine sandy and silty spots (biodisturbance)
25.00 - 59.00 idem, but more sandy and micaceous and with many darker clay spots; a pyrite concentration at 58-59 cm
59.00 - 87.50 grey-brownish much more sandy, micaceous and less sediment design, but still distinctly present; sand maximum between 67-72 cm
109. 252.90 - 253.92 (L: 66 cm - 40 cm geomechan. lab sample 253.47 - 253.87)
(continuous core, only broken in the upper 7 cm)
00.00 - 37.00 a grey-green very silty clay with a distinct sediment design ("linoleum like"); from 30 cm on, the pieces of dark clay are larger and larger; at 33 cm a larger 3 cm long pyrite concretion
37.00 - 66.00 darker grey-green less silty clay but still with smaller silty spots; at 59 cm a 4 cm long pyrite concretion; a little calcareous
110. 253.92 - 254.92 (L: 90 cm - 18 cm lab samples 254.71 - 254.89 m)
(continuous core, only fragmented over the first 3 cm)
Grey-brown very sandy clay and clayey sand, much sediment design: darker clay laminae and very light sand spots (tracks)
00.00 - 38.00 lighter brown clayey micaceous sand (many traces of broken up clay lenses and laminae) and whitish tracks at 15, 23, 26 and 28 cm; no chalk
38.00 - 63.00 darker grey-brownish very sandy micaceous clay, many broken up clay laminae; the contact at 38 cm is rather sharp; a larger track (4 cm long & 2 cm wide) filled up with sand starts at this contact
63.00 - 90.00 idem, but gradually to the bottom, more brown, sandy, micaceous and less clay spots (remains of clay layers and laminae)
111. 254.92 - 255.92 (L: 39 cm + 18 cm lab sample 255.19 - 255.37 m + 52 cm)
(continuous core, but regularly broken)
upper core:
00.00 - 09.00 brown finely stratified clayey sand, micaceous and with clay pieces in the lower half; a little calcareous
09.00 - 24.00 grey-brown very clayey micaceous sand to sandy clay, greater pieces of grey-green clay with fine silty spots, very intensively biodisturbed
24.00 an irregular limit with a grey sandy clay with a breccia-like design
24.00 - 39.00 grey-green silty compact clay with a distinct sediment design: dark clay in the silty clay and pale silty spots in the darker clay; some whitish points at 28 cm (gypsum)
lower core:
00.00 - 28.00 same grey-green silty compact clay with a distinct sediment design
28.00 - 52.00 more sandy and micaceous light grey-green silty clay with less but larger pieces of dark clay; only at 32 cm calcareous
112. 255.92 - 256.93 (complete core send to the geomechanical lab)
113. 256.93 - 257.93 (L: 88 cm - 20 cm lab sample 257.66 - 257.86 m)
(continuous core)
00.00 - 17.00 same light grey-green silty and a little sandy compact clay;
darker grey-green clay with small silty spots from 13 tot 17 cm, lower limit distinct but not sharp
17.00 - 25.00 grey-brown sandy and silty clay, micaceous, with many fragments of clay layers
25.00 - 88.00 brown very fine silty and very clayey sand, with distinct sediment design: clay fragments and same sandy track; from 50 to 69 cm rather a sandy clay; at the bottom a clayey sand with little sediment design; no chalk
114. 257.93 - 258.94 (L: 87 cm - 20 cm lab samples 258.72 - 258.92 m)
(continuous core)
00.00 - 16.00 grey-green sandy silty and micaceous compact clay with remains of clay laminae
16.00 - 27.00 green-brown, clayey sand micaceous with very few traces of clay laminae, only at the top a disturbed + 5 mm thick clay layer
27.00 - 46.00 grey-green sandy micaceous clay with small pieces of clay
46.00 - 87.00 grey-green micaceous, silty a little sandy clay with many dark clay fragments; black pyritic sand spots (tracks) at 43.55, 62 and 64 cm.
115. 258.94 - 259.95 (L: 86 cm - 20 cm lab sample 259.73 - 259.93 m)
(continuous core)
00.00 - 54/56 grey-green silty compact clay with may dark clay pieces, gradually more micaceous, more sandy and less pieces of dark clay, only traces of a larger clay layer, intensively biodisturbed, irregular limit below between 54-56 cm
56.00 - 80.00 grey-brown fine clayey sand with traces of biodisturbed clay lenses, the pure sand spots are very light-brown coloured.
80.00 - 86.00 irregular contact with a sandy clay and a vertical 7 cm deep perforation filled up with sand
116. 259.95 - 260.95 (L: 87 cm - 30 cm lab sample 260.62 - 260.92 m)
(continuous core)
00.00 - 21.00 grey-green brownish very sandy, micaceous clay, biodisturbed, clay laminae and layers
21.00 - 29.00 grey-brown clayey, micaceous sand, with some black pyritic lager sand tracks and traces of shells; calcareous; lower limit irregular from 29-32 cm
29.00 - 65.00 distinct but not sharp contact with a grey-green silty clay with many broken up, dark grey clay laminae; the top is perforated up to 40 cm (big track Ø 3 cm)
65.00- 87.00 same grey-green silty clay with only a few clay laminae and becoming more and more sandy & micaceous; traces of a shell at the bottom
117. 260.95 - 262.04 (L: 88 cm - 20 cm lab sample 261.81 - 262.01 m)
(continuous core)
00.00 - 62.00 grey-green brownish very sandy and silty, micaceous clay with remains of dark grey clay laminae, some pale sandy tracks; a little calcareous between 50-60 cm
62.00 - 88.00 idem, but gradually less sandy, more grey-green, no more brownish, intensively biodisturbed and in the upper zone several black pyritic points and elongated spots; at the bottom a compact silty and sandy clay
118. 262.04 - 263.05 (L: 88 cm - 18 cm lab samples 262.85 - 263.03 m)
(continuous core, at the top 5 cm fragmented)
00.00 - 45.00 grey-green compact silty and a little sandy clay, sediment design: broken up dark clay laminae, darker grey-green from 38 to 44 cm due to a higher concentration of dark clay layers
45.00 - 70.00 idem, but gradually increasingly sandy and micaceous; calcareous
70.00 - 88.00 grey-brown, very clayey micaceous fine sand, decreasing number of clay spots, traces of shells, calcareous; the upper limit is irregular from 69 to 72 cm and indistinct by the intense biodisturbance
119. 263.05 - 264.06 (L: 88 cm - 20 cm lab samples 263.83 - 264.03 m)
(continuous core)
00.00 - 17.00 grey-brown clayey micaceous fine sand with broken up clay laminae and with pale brown sandy tracks
17.00 - 70.00 gradually grey-green less sandy silty clay with many dark clay pieces, from 60 cm gradually less clay spots; shell traces at 63 cm; calcareous
70.00 - 88.00 grey-brown fine clayey micaceous sand, the clay spots are disappearing; calcareous
120. 264.06 - 265.07 (L: 86 cm)
(continuous core, broken at the top over 7 cm)
00.00 - 45.00 Brown-grey fine silty and micaceous sand, increasing number of clay spots (broken up clay laminae and layers), some sandy tracks are black pyritic, others are whitish; a concentration of dark clay spots between 26-36 cm; calcareous
45.00 - 51.00 dark grey-green thicker( + 1 cm) clay lenses with sandy joints in between and with very fine pale silty spots
51.00 - 86.00 same light grey-green sandy, silty and micaceous clay with many clay spots, some black pyritic points, from 65 cm on: decrease of the clay spots, except from 69-72 cm, increase of the sand content to become a grey-brown clayey homogeneous sand at the bottom, at 52 cm two larger shells of 1-2 cm
121. 265.07 - 266.06 (L: 83 cm - 20 cm lab sample 265.80 - 266.00 m)
(continuous core but between 27-34 cm open cracks - sand flow?)
00.00 - 38.00 brown fine silty and clayey, micaceous sand, dispersed biodisturbed clay laminae, a concentration of clay spots between 14-21 cm; lowest presence of clay between 27-35 cm: many pale sand spots); calcareous
38.00 - 73.00 gradually more clay, becoming a sandy clay, the clay occurs as clay spots; between 43-54 cm some larger pyritic black sandy spots (up to 5 cm long); sand zones between 54-58 cm and 70-73 cm
73.00 - 83.00 gradually less sandy, more silty and more clay spots (breccia-like)
122. 266.06 - 267.07 (L: 89 cm - 20 cm lab sample 266.84 - 267.04 m)
(continuous core)
00.00 - 32.00 grey-brown sandy, silty, micaceous clay with broken up clay laminae; traces of a shell at 23 cm; calcareous
32.00 - 67.00 the silty clay becomes gradually more and more sandy and micaceous to become finally a clayey sand at the bottom of that zone; calcareous
67.00 - 89.00 brown mottled fine clayey micaceous sand with a few clayey spots, very intensively biodisturbed; calcareous
123. 267.07 - 268.07 (L: 72.50 cm - 20 cm lab samples 267.70-267.90 + 15 cm)
(continuous core)
upper core:
00.00 - 25.00 grey-green silty, sandy and micaceous clay, many clay spots (broken clay laminae); very calcareous at the top
25.00 - 52.00 idem, but gradually brown-grey, more sandy, more micaceous and less clay spots
52.00 - 58.00 a lens shaped clayey sand, oblique limits on top and bottom, finely stratified; some joints are pyritic black, very micaceous; calcareous
58.00 - 72.50 grey-green sandy, very silty clay with larger clay spots (angular pieces of 2 mm thick clay layers, up to 1.5 cm long) some pale sandy spots; calcareous
lower core: grey-brown sandy and silty micaceous clay, with larger clay spots and a black sand spot(track), becoming a clayey micaceous and calcareous sand at the bottom
124. 268.07 - 269.08 (L: 67+15 cm - 18 cm lab samples 268.74 - 268.92 m)
(void of 26 cm in the middle of the upper core - lower core 15 cm)
upper core:
00.00 - 11.00 grey sandy clay, clay is biodisturbed, several pale sand spots (= tracks) very micaceous and calcareous
11.00 - 26.00 a grey-brown very micaceous and calcareous sand with some bigger biodisturbed clay spots
26.00 - 52.00 (empty core container, flushed out loose sand?)
52.00 - 67.00 grey-brown clayey sand, intensively biodisturbed, a pale sand layer, some pale sand spots, calcareous; at 58 cm a blackish pyritic sandy track Ø 15 mm
lower core: grey finely sandy, very silty compact clay with dark grey clay spots
(angular broken up clay layers); a larger horizontal sandy perforation at 4.5 cm: 4.5 cm long and 1.5 cm wide; very calcareous
125. 269.08 - 270.08 (complete core send to the geomechanical lab)
126. 270.08 - 271.08 (L: 89 cm - 20 cm lab sample 270.85 - 271.05 m)
(continuous core)
00.00 - 40.00 grey-brownish very clayey sand, micaceous; clear sediment design; many traces of biodisturbance; perforated clay layers, many sandy tracks Ø 1 cm, a larger vertical track, 10 cm deep Ø 1 cm, filled up with blackish pyritic laminated sand from 20-30 cm; between 30-37 cm, very clayey zone, perforations filled up with pale-grey loose sand; a pyritic track Ø 1 cm at 40 cm
40.00 - 71.00 dark-grey sandy clay, very homogeneous up to 60 cm, with only some pyritic spots; from 60-71 cm: more and more sandy
71.00 - 80.00 same sediment, but finely stratified and with traces of clay layers
80.00 - 89.00 a much less sandy, more silty clay, still micaceous and with many small pieces of clay laminae; the boundary at the top is perforated; at 84-86 cm also sandy perforation in the clay; non calcareous
127. 271.08 - 272.08 (L: 88 cm - 20 cm lab sample 271.83 to 272.03 m)
(continuous core - fragmented over 7 cm at the top)
00.00 - 30.00 grey-green sandy micaceous clay, at the top many dark clay, gradually increasing sand content to become a brown homogeneous, very sandy clay or clayey sand
30.00 - 38.00 downwards rapidly increase of the clay content, at the base of this zone a 1 cm thick laminated layer of pure dark grey clay, at 35 cm a curved oblique perforation filled up with black pyritic sand
38.00 - 41.00 a finely laminated clayey very micaceous sand layer; at 41 cm: a 5 mm thick oblique layer of dark pure clay
41.00 - 60.00 Brown-grey clayey sand, very homogeneous, at the top over 5 cm, 3 thin clay layers, perforated by biodisturbance; at 54 cm an other clay layer with just below a 1 cm thick sand layer (or a perforation)
60.00 - 88.00 from 65 cm on gradually less sandy to become at the bottom a grey very silty and less sandy clay with many broken up clay laminae
128. 272.08 - 273.08 (L 88.50 cm - 20 cm lab sample 272.85 - 273.05 m)
(continuous core)
00.00 - 20.00 grey-green compact silty clay with many angular broken up clay laminae
20.00 - 40.00 idem, but decrease of the clay spots and increase of the sand content
40.00 - 77.00 grey-brownish sandy clay, the clay spots are very indistinct, more biodisturbance
77.00 - 88.50 very micaceous clay, very intensively biodisturbed, no distinct sediment design but increased sand content; also many small pale sand spots; at the bottom more a brown clayey sand; no chalk in the whole core
129. 273.08 - 274.08 no core
130. 274.08 - 275.08 (L: 88 cm - 20 cm lab samples 274.85 - 275.05 m)
(8 - 24 cm: core disturbed by cracks - due to desiccation of a water saturated zone? - 57 - 70 cm: core completely fragmented)
00.00 - 02.00 a lens brown fine laminated sand
02.00 - 08.00 green very sandy clay, very little sediment design, some pale sandy spots, some blackish and pyritic dots, micaceous, no chalk
08.00 - 24.00 same green sandy clay but disturbed cracks by drying up
24.00 - 57.00 grey-green compact sandy and silty clay, with more sediment design, many traces of clay laminae, pyretic dots, at 41 cm a sand lens, very micaceous and pyritic
57.00 - 70.00 some grey-green silty and sandy clay (completely fragmented core); no chalk
70.00 - 82.00 dark-green very sandy clay, micaceous, calcareous, indistinct traces of clay laminae, intensively biodisturbed
82.00 - 88.00 paler grey-green silty, sandy and micaceous clay, many darker clay spots (broken up clay laminae); calcareous
131. 275.08 - 276.08 (L: 88 cm - 20 cm lab sample 275.84 - 276.04 m)
(continuous core)
00.00 - 20.00 pale grey-green silty and sandy compact clay, very fine darker clay spots (remains of clay laminae); a shell at 13 cm; calcareous
20.00 - 36.00 idem, but more sandy and glauconiferous, to the bottom more and more green glauconite sand in the tracks, decreasing number of dark-grey clay spots
36.00 - 70.00 green loose, glauconitic sand with a few very indistinct remains of clay layers, pale-green sand spots (filling up of tracks), micaceous, calcareous
70.00 - 79.00 light-green more silty sand: lower limit is rather sharp and undulating
79.00 - 88.00 - 2 cm light-brown fine silty sand with very many fine pieces of clay laminae, small perforations with glauconitic sand
- 4 cm: idem, but the clay pieces are larger and less dense, a large (2.5 cm long) track with green sand,
- 3 cm very pale-brown (beige) micaceous clayey and silty sand, with few clay spots and at the bottom a sand track filled with brown sand; calcareous
132. 276.08 - 277.08 (L: 88 cm - 18 cm lab samples 276.86 - 277.04 m)
(continuous core, broken in 9 main pieces)
Light grey-green very silty and sandy compact clay, a shell at 21 cm; calcareous
the most sandy zones are: 0-9 cm and 48-53 cm; the zone 25-46 cm contains moderately clay spots (broken clay laminae) and the zone 53-82 cm more densely
133. 277.08 - 278.08 (L: 87 cm - 18 cm lab sample 277.86 - 278.04 m)
(seriously fragmented core from 62 to 82 cm)
00.00 - 03.00 a grey-green very sandy clay
03.00 - 75.00 darker grey-green compact silty clay; from 3-18 cm larger clay layers with fine silty spots and some more sand spots; from 18-75 cm dispersed distinct remains of 2 mm thick clay laminae with a higher concentration between 20-30 cm and 42-49 cm; larger sand lenses at 18-20 cm, 25 cm and 49-51 cm; several pyritic spots; traces of shells at 39, 45, 51, 64 cm
75.00 - 87.00 darker grey-green, very sandy micaceous clay with a clayey zone from 81-84.50 cm composed of breccia-like pieces of clay in a pale silty mass
134. 278.08 - 279.08 (L: 81 cm - 20 cm lab sample 278.84 - 279.04 m)
(on top 5 cm "rubbish" - continuous core)
05.00 - 17.00 dark-green glauconitic clayey micaceous and calcareous sand with at 8-9 cm a dark-grey perforated clay layer, 10 mm thick; underneath only traces of strongly biodisturbed clay layers; a relatively sharp limit at the bottom
17.00 - 81.00 grey-green compact silty and sandy micaceous clay with many very fine broken up clay laminae, larger perforations filled with dark green glauconite sand at 20 and 26 cm; between 36-49 cm: a concentration of many very fine perforations (Ø 1-2 mm) filled up with darker greenish sand; very calcareous at the bottom
135. 279.08 - 280.08 (L: 87.50 cm - 18 cm lab sample 279.83 - 280.01 m)
(continuous core, only 7 cm fragmented on top)
00.00 - 07.00 same grey-green very silty calcareous clay
07.00 - 61.00 dark-green clayey glauconitic sand, clay present as remains of perforated clay layers; more clay from 7-17 cm, decreasing to the bottom of that zone; at 28-37 cm and 39-56 cm a concentration of pale sand spots; more clayey between 37-39 cm and at 54 cm a larger perforated clay lens (2 cm thick)
61.00 - 87.50 a grey-green very silty and sandy clay, with many broken up and biodisturbed clay laminae, larger sandy perforations at 67, 72, 80 and 81 cm; very calcareous at the bottom
136. 280.08 - 281.08 (L: 78.50 cm - 20 cm lab sample 280.82 - 281.02 m)
(at the top 5 cm rubbish - continuous core)
00.00 - 05.00 grey soft clay = rubbish
05.00 - 58.00 dark-green glauconitic and micaceous clayey sand with intensively biodisturbed dark-grey clay layers, pale-green spots and layers between 5-25 cm and 43-58 cm; with clayey zones from 8-22 cm; at 56.50 cm trace of a shell
58.00 - 78.50 a light grey-green very silty, micaceous and sandy clay, clay occurs in many remains of biodisturbed clay laminae; many perforations filled up with green glauconite sand; slightly calcareous
137. 281.08 - 282.08 completely missing core
138. 282.08 - 283.04 (L: 81+10 cm, 28 cm lab samples 282.72 - 283.00 m)
(continuous cores - lab samples taken between the two pieces; 0-8 cm probably disturbed during coring operation)
upper core:
00.00 - 08.00 grey clay, sandy clay and clayey sand, disturbed
08.00 - 59.00 dark-green clayey sand or sandy clay, calcareous; clay occurring in irregular spots and mottles, intensively biodisturbed; the sand contains a coarse fraction of quartz and glauconite grains; light-green mottles of medium and coarse sand occur in the upper half (11-38 cm); at 53-55 cm a thin oblique layer or joint of coarse sand grains; at 59 cm a brown reddish irregular concretion (siderite?)
59.00 - 81.00 dark green-grey fine clayey sand, very fine clay spots; mottled sand, intensively biodisturbed; no chalk
lower core:
00.00 - 10.00 same dark-green clayey sand; at 2 cm a clay fragment (2.5 cm long); no chalk
139. 283.04 - 284.04 (L: 88 cm - 20 cm lab sample 283.81 - 284.01 m)
(continuous core)
Dark-green very clayey micaceous sand; clay very irregularly distributed around tracks and perforations; a long track from 24-34 cm, Ø 1 cm; at 33 cm a pale-green sand layer; from 35-65 cm: distinct clay spots, but also intensively perforated and biodisturbed; from 65-88 cm: again clayey sand with many pale spots and only a few dark clay spots; from 83-88 cm: more clay spots; from 46 cm on: presence of a fraction of coarse quartz grains
140. 284.04 - 284.45 (L: 70 cm - 20 cm lab sample 284.25 - 284.45 m)
(continuous core: on top 9,50 cm disturbed core of soft clay = rubbish:, from 50-70 cm: the core represents 4 main open cracks)
Remark: drilling length 41 cm, core length 70 cm!?
00.00 - 09.50 green glauconitic clayey sand with inflow of clay
09.50 - 70.00 dark-green fine and medium fine clayey sand, intensively biodisturbed, very few clay spots; the clay is very irregularly distributed in the sand; no chalk
141. 284.45 - 285.23
(no recovery - empty core container)
142. 285.23 - 286.33
(no recovery - empty core container)
143. 286.33 - 287.33 (L: 83 cm - 18 cm lab samples 287.07 - 287.25 m)
(continuous core)
Same green clayey micaceous fine to medium fine sand, the sand is mottled by the biodisturbance, only a few dispersed dark grey clay pieces and many pale-green sand mottles, some distinct tracks with a clay drape at the border: 5 cm long, 1 cm wide and filled up with pale-green loose sand; no chalk
144. 287.33 - 288.17 (L: 87 cm - 18 cm lab samples 287.99 - 288.17 m)
(fragmented core: 5-15 cm and 40-57 cm)
Light grey-greenish a little sandy, clay and silt, compact very calcareous micaceous with locally concentration of whitish fine (up to 1 mm thick), spots due to biodisturbance at 25, 70, 82 cm; at 1-5 cm, 25-29 cm, 58-60 cm, same black pyritic dots and sandy joints; only a few remains of dark-grey clay laminae between 23-30 cm.
145. 288.17 - 289.17 (L: 88 cm - 20 cm lab sample 288.97 - 289.17 m)
(continuous, but dried out core)
Light grey-green very finely sandy silt and clay, micaceous, very homogeneous, only a few spots with black pyritic sands visible; sometimes laminated (as at 85 cm); traces of shells at 8, 43 and 84 cm; very calcareous
146. 289.17 - 290.17 (L: 63.50 cm - 40 cm lab sample 289.77 - 290.17 m)
(continuous core)
Same light grey-green sandy silt and clay, very micaceous and calcareous; indistinct remains of fine laminae of green clay concentrated at several levels: 6-13 cm, 20-30 cm, 38-50 cm; at 54 cm a black pyritic sand spot
147. 290.17 -291.07 (L: 88.50 - 20 cm lab samples 290.84 - 291.04 m)
(continuous but disturbed core, frequently divided horizontally: 4-20 cm and 65-88.50 cm)
00.00 - 07.00 same sandy silt and clay
07.00 - 88.50 grey-green more sandy and micaceous, very calcareous silt and clay, some fine glauconite grains; more clayey (25-38 cm, 44-50 cm, 61-66 cm) with very indistinct remains of clay laminae; black pyritic sand spots at 14, 38, 48, 64, 70, 73 cm; some larger sand tracks
148. 291.07 - 292.08 (L: 87 cm - 20 cm lab sample 291.88 - 292.08 m)
(continuous core)
Green fine very clayey micaceous sand, calcareous 0- 40 cm, downwards poorly calcareous, shell at 22 cm and a larger thick walled shell 5 cm long at 35 cm; the clay is not completely homogeneously mixed up with the sand: there are traces of clay layers between 35-65 cm, occurrence of scattered pale sandy spots or dots; some indistinct tracks at 60-64 cm
149. 292.08 - 293.08 (L: 86 cm - 20 cm lab sample, 292.88 - 293.08 m)
(continuous core)
00.00 - 43.00 grey-brownish sandy and micaceous clay, no chalk; sediment design: dark-grey clay with very fine pale silty spots; larger tracks filled up with more brownish micaceous fine sand at 13 cm (4 cm long, 2 cm wide), at 15 cm (Ø 1.5 cm) and from 18-22 cm a lateral one, Ø 1.5 cm
43.00 - 86.00 lighter brownish more silty and less sandy clay, with very little sediment design: only some very indistinct darker spots; at 70 cm a concentration of micaceous very fine pale sandy spots and a circular clayey spot (Ø 1 cm), a shell point at 83 cm, in the lowest 6 cm again presence of very fine pieces of clay (broken up clay laminae); no chalk
150. - 293.08 - 294.04 (L: 87 cm - 20 cm lab sample 293.84 - 294.04 m)
(continuous core)
00.00 - 08.00 same light grey-brownish sandy silt, an undulating lower limit at 5.5 cm a larger rounded piece of grey-greenish clay with very distinct whitish silty spots; very calcareous
08.00 - 43.00 same silt, but clearly more sandy and micaceous; dispersed darker clay spots and a few pyritic spots or fine tracks
43.00 - 78.00 idem, but more micaceous and sandy, less clayey
78.00 - 87.00 again a pale grey-brownish sandy silt, with only a few pyritic sand spots in the upper 7 cm of the zone; no chalk
151. 294.04 - 295.02 (L: 87 cm)
(continuous core but fragmented between 20-30 cm)
00.00 - 10.00 brown-grey clayey sand, micaceous with fine lamination, but disturbed by biodisturbance, many small elongated pale spots, no chalk
10.00 - 20.00 idem, more clayey and some dark grey spots of clay (intensively biodisturbed)
20.00 - 30.00 disturbed zone, probably less clayey, water saturated and flown out
30.00 - 50.00 same sediment fine pale spots and some remains of clay pieces
50.00 -100.00 same very micaceous clayey fine sand, very finely mottled, fine sandy spots by biodisturbance; no chalk
152. 295.02 - 296.02 (L: 75cm - 20 cm lab sample 295.82 - 296.02 m)
(continuous core)
Same brown clayey fine micaceous sand, finely mottled, a more clayey zone with remains of clay pieces between 30-40 cm; the most strongly mottled zones are 0-15 cm and 60-75 cm; no chalk
153. 296.02 - 297.12 (L: 72 cm - 18 cm lab samples 296.83 - 297.01 m)
(continuous core, 6 cm rubbish on top; from 27-72 cm: the core is frequently horizontally torn)
Same sediment, but the colour is distinctly more green than brown; the most mottled zones: 0-30 cm and 60-7 cm; same indistinct remains of clay pieces between 18-23 cm; between 46-60 cm: larger tracks: some are very pale, others pyritic black; some very fine glauconite grains; no chalk
154. 297.12 - 298.05 (L: 85cm - 20 cm lab sample 297.82 - 298.02 m)
(continuous core, 4 cm rubbish soft clay on top; between 60-80 cm core is frequently horizontally torn up)
Same green grey clayey fine micaceous sand, with visible distorted clay layers between 10-48 cm and 77-85 cm; mottled sand with maximum at 38-40 cm and 48-66 cm, intensively biodisturbed; no chalk
155. 298.05 - 299.05 (L: 81 cm - 20 cm lab sample: 298.81 - 299.01 m)
(continuous core, 5 cm rubbish soft clay on top of the core)
Same grey-green clayey very micaceous fine sand, intensively biodisturbed with a few remains of perforated and biodisturbed dark-grey clay lenses between 10-15 cm; traces of clay: 37-60 cm and 75-81 cm; very mottled sand, pale spots, larger tracks at 27 cm and between 34-53 cm; no chalk
156. 299.05 - 299.94 (L: 70 cm - 20 cm lab sample 299.70 - 299.90 m)
(continuous core, 12 cm rubbish soft clay and sand above it; frequently horizontally torn core from 33-44 cm)
00.00 - 33.00 dark grey-green very clayey fine micaceous sand, some indistinct remains of clay layers.
33.00 - 48.00 less clayey, some pyritic spots.
48.00 - 70.00 more clayey sediment or even a sandy clay with many perforations filled up with sand with glauconite grains; also some black pyrite sand spots; no chalk
157. 299.94 - 300.94 (L: 87 cm - 18 cm lab samples 300.69 - 300.87 m)
(continuous core)
00.00 - 30.00 dark-green very clayey fine micaceous and glauconitic sand, glauconite is very altered and pulverized, only very small glauconite grains; between 7-30 cm: thicker clay layer (up to 2 cm thick) completely perforated and disturbed by biodisturbance, 8-22 cm: several smaller tracks filled with glauconitic sand
30.00 - 45.00 green nearly homogeneous glauconitic sand
45.00 - 87.00 again several relicts of clay layers, completely perforated; at the bottom very dark-green and with some black pyritic sand tracks.
158. 300.94 - 301.94 (L: 79 cm - 30 cm lab sample: 301.60 - 301.90 m)
(continuous core, but zone 33-79 cm is frequently horizontally torn)
00.00 - 18.00 oblique dark-grey layer pure clay with sand joints and frequently perforated; at 14 cm a track Ø 3 cm filled up with green sand; very dark-green clayey micaceous sand, no chalk
18.00 - 79.00 same sand, but very few traces of clay layers and laminae, same pale small sandy tracks; no chalk
4. Geological interpretation
4.1. Overview
Top * Base * STRATIGRAPHIC UNITS
00.00 - 46.00 m Kempen Groep
46.00 - 66.00 m Merksplas Formation
66.00 - 84.60 m Lillo Formation
80.70 - 84.60 m Luchtbal Member
84.60 - 95.00 m Kattendijk Formation
95.00 - 125.00 m Diest Formation
115.00 - 125.00 m Dessel Member
125.00 - 142.00 m Berchem Formation
142.00 - 153.45 m Voort Formation ?
153.45 - 280.00 m (or 270 m) 1i Boom Formation
153.00 - 200.00 m Wo to W3 (informal)
200.00 - 237.62 m Putte Member
231.34 - 233.20 m DB-layer
237.62 - 259.50 m Terhagen Member
242.75 Pink-layer
259.50 - 281.08 m Belsele-Waas Member
281.08 - 340.00 m Zelzate Formation
281.08 - 287.33 m Ruisbroek Member
287.33 - 299.00 m Wintham Member ?(silt)
299.00 - 304.00 m Watervliet Member ?
304.00 - 340.00 m (cored up to 301,94 m) Bassevelde Member
340.00 - 410.00 m Maldegem Formation
340.00 - 355.00 m Onderdijke Member (a3)
355.00 - 362.00 m Buisputten Member (s2)
362.00 - 377.00 m Zomergem Member (a2)
377.00 - 383.00 m Onderdale Member (s1)
383.00 - 396.00 m Ursel Clay
396.00 - 400.00 m Asse Clay
400.00 - 410.00 m Wemmel Zand
410.00 - 426.00 m Lede Formation
426.00 - 437.50 m Brussel or Gent Formation
437.50 - 476.00 m Gent Formation
437.50 - 448.00 m Vlierzele Member
448.00 - 470.00 m Pittem Member
470.00 - 476.00 m MerelbekeMember
476.00 - 505.00 m (T.D. borehole) Tielt Formation
AUTHOR: P.LAGA - Belgian Geological Survey - June 2006
1 Between 270 m en 280 m occurrence of an alternation of sandy clay and clayey sand. According to N. Vandenberghe's opinion, the base of the Boom Clay Formation should be at 270 m. However, I'am disposed to include the zone 270 - 280 m to the Boom Formation. Only from the depth of 280 m, forms the sediment a real aquifer. Later, the results of laboratory test may give a decisive answer.
4.2. Comment
4.2.1.The Pleistocene and Neogene Formations
The base of the Kempen Group, the Merksplas, Lillo and Kattendijk Formations is taken from an older partially cored (75 to 100 m) well (001E-044), 120 m deep, drilled at the same locality (at a few meters distance of the actual well) and with geophysical logs. The two geophysical logs fit very well.
The base of the Kempen Group and of the Merksplas, Lillo and Kattendijk Formations can be borrowed from the neighbouring older well. The older geophysical log recorded by TNO - Dienst Grondwaterverkenning is, concerning the Neogene deposits, quite identical with the actual log. Some gamma ray peaks within the Lillo Formation seem to have a depth difference of about 1 to 1,5 m. Only the signature of the gamma ray log of the lower part of the Lillo Formation, corresponding with the Luchtbal Sands Member, is clearly different and shows several much more important variations.
The variations of the resistivity log within the Diest formation are surprisingly similar in both logs.
In the first place, the interpretation of borehole nr. 001E-044 is based on its cored section and especially the upper and lower boundary of the Luchtbal Sand Member and the boundary between the Kattendijk and the Diest Formations could be very well observed and concluded.
4.2.2.The Oligocene Formations
The presence of the Voort Formation (Chattian) and the Eigenbilzen Formation between 142 and 153 m is completely hypothetical and is only based on the geophysical log signature. The cores of this level are rather less reliable and the sediment is non calcareous, so that micropaleontological investigations (foraminifera and nannoplankton fossils) can not offer a solution.
The resistivity at the base of the Berchem Formation shows a higher curved pattern combined with an unchanged gamma ray curve. However, in a nearby well (Wuustwezel nr. 015E-298 corresponding to the S19 of the SCK-CEN), the same higher curved pattern of the resistivity at the base of the Neogene is accompanied by a considerable lower gamma ray. In the Essen well, just above the Boom Clay Formation, a lower curved pattern of the gamma ray occurs as well, but there is no corresponding higher curved pattern present in the resistivity log.
Comparing three differing geophysical well logs nearby (Essen, Wuustwezel and Brasschaat (nr. 015E-0267 = S37 of the SCK-CEN), the boundary at the top of the Boom Clay Formation is three times different. In the Brasschaat well, this boundary is not marked in the gamma ray log, accompanied with a marked higher curved pattern in the resistivity. A similar resistivity pattern is found in the Wuustwezel well, but not in the Essen well. On the other hand, the gamma ray logs of Wuustwezel and Essen show a section with a noticeable lower gamma ray intensity of 5 m thickness in the Wuustwezel well and 8 m in the Essen well. The thickness of the Berchem Formation is 21 m in Brasschaat, 24 m in Wuustwezel and 17 m if the presence of the Eigenbilzen/Voort Member is accepted and 28 m if the whole section from 125 to 153,45 m is considered as Miocene. There are arguments for both solutions, but no conclusive evidence. However, the presence of the Voort Formation (Chattian) is likely but the presence of the Eigenbilzen Formation is not.
The Boom Formation is much thicker (126.68 m) than in the neighbourhood of the city of Antwerp (103 m in the Brasschaat well and 108 m in the Wuustwezel well). The upper part of this clay package corresponds to the upper part found in the Weelde well and the informal lithologic units W0 to W3 can be distinguished (see Vandenberghe et al. 2001 - Aardkundige Mededelingen 11).
The top of the Putte Clay Member is put at 200.21 m, the top of the wax-like very compact clay covered with a more silty clay.
The septaria with many calcareous wormlike tracks at 229.30 m may be according to the description the S60 septaria layer.
The DB (double-band) is possibly at 232 m, more exactly between 231.34 and 233.20 m with a pure wax-like clay in the middle between 231.80 and 232.78 m. However, the geophysical log do not allow to locate unmistakable the DB (see the preliminary remarks).
The boundary Putte / Terhagen Clay is characterized by a change in colour from the dark blackish Putte Clay to the more brown Terhagen Clay. This change in colour is accompanied by fluctuations, but at 237.62 m the brown colour is continuously present and is considered as the lithologic boundary between these two members.
During the description of the still humid cores, the pink layer was found at 242.80 m and is also visible on the photographs.
The boundary between the Terhagen and the Belsele-Waas Members is described between 54/56 cm below the top of the core nr. 115 and corresponds, approximately with the depth of 259.50 m. At this depth a change of a compact silty clay in a fine clayey sand and sandy clay occurs. At this level, also an outlined decrease of the gamma ray log starts.
The base of the Belsele-Waas Member could be placed at different levels because the presence of an alternation of sandy clay en clayey sand. The zone between 270 and 281 m consists mainly of sandy clay with some intercalations of green clayey very fine glauconitic sand, as there are: between 275.44 and 275.87 m, 279.08 and 279.69 m, 280.86 and 280.66. However, the clay layers between 279.69 and 279.83 (the bottom of the available core) and between 280.66 and 280.86 are compact and don't fit within the definition of the Ruisbroek Sands Member.
As core nr. 137 is completely missing, we assume that the sediment was very loose. The next core, nr. 138 (282.08 to 283.04 m) contains a coarse fraction of quartz and glauconite grains and belongs without a doubt to the Ruisbroek Member. Therefore we opt for the upper boundary of the Ruisbroek Member at the level of 281.08 m. That is exactly the level where the resistivity starts importantly to rise.
At the depth of 287.33 m starts a silt and clay packet that may correspond with the Wintham Silt Member. As the geographical extent of this member is not well known nor the facies changes in northern direction, the presence of this member is uncertain. Only micropaleontological investigations can give a decisive answer to the question if this section is part of the Ruisbroek Member or of the Wintham Member. As the sediment between 287.33 and 292.80 m is very calcareous this expectation is realistic.
The presence of the Watervliet Clay Member from 299.00 to 304.00 m, based on the high gamma ray peak, is speculative. In fact the sediment description shows a clayey and very glauconitic sand with some clay layers. It is difficult to give an decisive answer if this section belongs to this member or to the underlying Bassevelde Sand.
4.2.3.The Eocene Formations
All the other boundaries mentioned in the lithostratigraphic interpretation are based on the similarities of the geophysical logs (mainly the gamma ray and resistivity curves) with the neighbouring deep wells of Brasschaat and Wuustwezel, where these formations and members were also encountered. The interpretation of the section between 426 and 437 m depth is questionable , but referring to the Woensdrecht well, the presence of the Brussel Formation above the Gent Formation is acceptable.
Surprising is the bigger thickness (16 m) of the Lede Formation. The difficulty to recognize the boundary between the Lede and the Brussel Formation in northern well may be an explanation for this anomaly.
The Gent Formation is composed of 10.5 m Vlierzele Member on top, 22 m Pittem Member and 6 m Merelbeke Member at the base.
The deepest struck Formation is the Tielt Formation with the Egem Member. The presence of the Aalbeke Clay is not demonstrated.
ANNEX :
Photos of cores
1 (Studiecentrum voor Kernenergie - Centre d'étude de l'Energie Nucléaire
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Essen borehole - 001E0071
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Essen borehole - 001E0071
1
Essen borehole - 001E0071
