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We focused mainly on dredging, with the aim to recover basalts and fresh
volcanic materials. Additional sampling was performed by grab and gravity corer.
The location and description of the samples are located in Tab.7.
Eleven sites were dredged for rock samples from submarine slopes and
escarpments in and around the Thetis Deep. Two dredgers were lost during
the operation. Four dredge samples contained basalts, while practically all other
dredges contained abundant carbonate crusts. The carbonate crusts
consist mostly of pteropods and foraminifera with little or no evidence
for calcareous benthic organisms.
The basalts will be subjected to intense geochemical (major and trace elements, Nd,
Sr, Os and other isotopes, water content, melt inclusions) and geochronological
analyses, especially on the glasses of the pillows.
Some of the basalt samples show a thick crust of laminated authigenic carbonates,
which will be analysed by isotopic methods and radiometric dating to provide an
insight into the processes responsible for basalt emplacement.
Table 8 gives details on the rock description,
subsampling and delivery. These samples will be analysed for standard
geochemical and petrographic analysis.
Grab samples (GR01 to GR04) in the Main Trough to the west
(outside) of the Thetys Deep, at depths between 700 and 800 m, revealed
carbonate ooze and sands, rich in foraminifera and pteropods, with only
little associated macrofauna (Argonauta argo, Cuspidaria sp., etc.).
Grab GR05 at 1196 m water depth at the margin of the main Red Sea trough
towards the 1600 m deep Conrad Basin reavealed very similar
foram/pteropod ooze, pointing to a widely uniform sedimentation in the
Main Trough above the axial valley and the aligned central deeps.
The gravity core at 750 m revealed a 3.3 m sequence of carbonate ooze,
containing carbonate crusts. Further analyses (clay mineralogy,
micropaleontology and geochemistry) will be taken out after cutting of the
PVC-liner.
Table 7:
Samples location. DR*=dredges(start,end),GR*=grabs, CR*=core.
CCR=Carbonate Crust, VG=Volcanic Glass, BAS=Basalt,
DSC=Deep Sea Coral, VS=Volcanic Scoria, CM=Carbonate Mud.
|
CRUISE RS05 |
R/V URANIA |
|
|
|
|
|
ID |
DATE |
LON |
LAT |
RECOVERY |
LITHOLOGY |
|
|
|
ddmm.xxxx(E) |
ddmm.xxxx(N) |
Kg |
|
|
|
|
|
|
|
|
|
DR-01 |
2005-01-11 |
3737.2507 |
2237.8982 |
Bottom |
|
|
DR-01 |
2005-01-11 |
3736.8137 |
2237.5009 |
0.01 |
CCR-100% |
|
DR-02 |
2005-01-11 |
3737.3711 |
2237.8701 |
Bottom |
|
|
DR-02 |
2005-01-11 |
3737.4949 |
2238.3749 |
200 |
CCR100%;VG |
|
DR-03 |
2005-01-11 |
3740.9743 |
2237.4635 |
Bottom |
|
|
DR-03 |
2005-01-11 |
3740.4707 |
2238.2590 |
80 |
BAS-100% |
|
DR-04 |
2005-01-12 |
3756.9860 |
2214.8418 |
Bottom |
|
|
DR-04 |
2005-01-12 |
3756.8966 |
2215.0812 |
lost |
- |
|
DR-05 |
2005-01-13 |
3758.6531 |
2215.3196 |
Bottom |
|
|
DR-05 |
2005-01-13 |
3757.0000 |
2215.6667 |
0.1 |
CCR-100% |
|
DR-06 |
2005-01-13 |
3757.6376 |
2215.1408 |
Bottom |
|
|
DR-06 |
2005-01-13 |
3757.5254 |
2215.7036 |
1.5 |
CCR-100%;DSC |
|
DR-07 |
2005-01-13 |
3746.4602 |
2224.4240 |
Bottom |
|
|
DR-07 |
2005-01-13 |
3745.8987 |
2225.4049 |
100 |
CCR-99%;VG-1% |
|
DR-08 |
2005-01-13 |
3744.6801 |
2225.4528 |
Bottom |
|
|
DR-08 |
2005-01-13 |
3744.5807 |
2226.3536 |
100 |
CCR-99%;BAS+VG-1% |
|
DR-09 |
2005-01-13 |
3733.3787 |
2246.2928 |
Bottom |
|
|
DR-09 |
2005-01-14 |
3733.9083 |
2246.6215 |
lost |
- |
|
DR-10 |
2005-01-14 |
3734.4479 |
2245.4369 |
Bottom |
|
|
DR-10 |
2005-01-14 |
3734.4956 |
2246.4705 |
100 |
CCR-40%;BAS-60% |
|
DR-11 |
2005-01-19 |
3649.7052 |
2349.2532 |
Bottom |
|
|
DR-11 |
2005-01-19 |
3649.1850 |
2350.0249 |
200 |
CM100%;CCR+VS(?) |
|
GR-01 |
2005-01-14 |
3743.9979 |
2318.7070 |
full |
CM |
|
GR-02 |
2005-01-14 |
3749.6070 |
2316.0934 |
full |
CM |
|
GR-03 |
2005-01-14 |
3753.3277 |
2310.9918 |
full |
CM |
|
GR-04 |
2005-01-14 |
3754.5438 |
2304.9869 |
full |
CM |
|
GR-05 |
2005-01-14 |
3443.7108 |
2707.3094 |
full |
CM |
|
CR-01 |
2005-01- |
3759.0667 |
2259.7504 |
3.3m |
CM-CCR(bottom) |
|
Table 8:
Rock description, subsampling and destination.
CCR=Carbonate Crust, VG=Volcanic Glass, BAS=Basalt,
DSC=Deep Sea Coral, VS=Volcanic Scoria.
|
Sample |
Type |
Size(cm) |
Description |
subsamples to |
|
|
|
|
|
|
|
DR01-01 |
CCR |
4x3x0.3 |
consolidated carbonate enriched in pteropods and forams. Layered. |
ISMAR |
|
DR02-01 |
VG |
very small fragments |
fresh basaltic glass |
ISMAR |
|
DR02-02 |
CCR |
various size |
consolidated carbonate enriched in pteropods and forams. |
ISMAR-UR-SGS |
|
DR03-01 |
BAS |
30x15x20 |
moderately vesicular pillow basalt. Rare Plagioclase phenocrysts (1%) up to 1 cm in size. Vesicles are empty and up to 4mm in diameter. Fresh glassy crust up to 3 cm in thickness. Outer glassy surface of pillow is coated with thin Fe-Mn film. Interiorior fractures of pillow show a concentric alteration and are partly coated with Fe-Mn film. |
ISMAR-UR-SGS-SCU |
|
DR03-02 |
BAS |
30x26x6 |
vesicular basalt (vesicles are empty and up to 0.5 cm in diameter), sheet flow. Very rare plagioclase phenocryst (up to 3mm). 1 cm thick glassy crust coated with thin Fe-Mn film. Outer surface is then coated with soft light-brown carbonatic sediment. |
ISMAR-UR-SGS-SCU |
|
DR03-03 |
BAS |
25x24x9 |
vesicular basalt (vesicles are empty and 0.1-3 mm in diameter), sheet flow slightly fractured. Very rare plagioclase phenocryst (up to 3mm). 1 cm thick glassy crust. Thin Fe-Mn coat. |
ISMAR-UR-SGS-SCU |
|
DR03-04 |
BAS |
20x20x5 |
same as 03-03, not fractured |
ISMAR-UR-SGS-SCU |
|
DR03-05 |
BAS |
18x17x4 |
same as 03-04 |
ISMAR-UR |
|
DR03-06 |
BAS |
12x7x6 |
same as 03-04, but thin glassy crust |
ISMAR-UR-SGS-SCU |
|
DR03-07 |
BAS |
10x7x4 |
same as 03-02 but 2 cm thick glassy crust |
ISMAR-UR |
|
DR03-08 |
BAS |
4 pieces about 10x5x3 |
vesicular basalt similar to 03-02 with thin glassy crust and soft sediment encrusting the outer surface |
ISMAR-UR-SGS-SCU |
|
DR03-09 |
BAS |
10x7x4 |
same as 03-07 |
ISMAR-UR |
|
DR03-10 |
BAS |
9x6x6 |
same as 03-06 |
ISMAR-UR-SGS-SCU |
|
DR03-11 |
BAS |
17x11x3 |
same as 03-02 but no fresh glass |
UR |
|
DR03-12 |
BAS |
9 centimetric pieces |
several pieces of lava flow, tabular with fresh glassy crust. Samples have been named with progressive letter A to I. A to ISMAR, B and C to UR, D to SGS, E to Egypt |
ISMAR-UR-SGS-SCU |
|
DR03-13 |
BAS |
bag of several small pcs. |
several pieces of lava flow, tabular with fresh glassy crust |
|
|
DR05-01 |
CCR |
3 pieces |
small fragments of pteropods-rich carbonate crusts |
ISMAR-UR-SGS |
|
DR06-01 |
CCR |
various size |
|
ISMAR-UR-SGS-SCU |
|
DR07-01 |
VG |
very small fragments |
few small fragments of fresh basaltic glass |
ISMAR |
|
DR07-02 |
CCR |
various size |
|
ISMAR-UR-SGS |
|
DR08-01 |
BS |
15x10x8 |
slightly vesicular basalt with a 1 cm thick fresh glassy crust. The outer surface is covered by a 1 cm thick layered carbonate crust. |
ISMAR-UR |
|
DR08-02 |
VG |
very small fragments |
several small fragments of fresh basaltic glass |
ISMAR |
|
DR08-03 |
CCR |
various size |
|
ISMAR-UR-SGS |
|
DR10-01 |
BAS |
30x30x30 |
porphyric pillow basalt. Phenocrysts of Olivine up to 0.7 cm and Plagioclase up to 0.5 cm. Visible melt inclusions in both Ol and Plg. 1 to 2 cm. Rare very small vesicles. Thick glassy crust partly coated with a thin Fe-Mn crust. |
ISMAR |
|
DR10-02 |
BAS |
22x16x11 |
slightly vesicular basalt with 0.5 to 1 cm thick fresh glassy crust.
The basalt is moderately altered. The outer surface is covered with a thick carbonatic
layer which looked crystallized calcite or aragonite. The carbonatic layer is itself
covered with a  1 mm thick Fe-Mn crust. a smaller similar piece has been named 10-02b |
ISMAR-UR |
|
DR10-03 |
BAS |
17x13x6 |
Plg-Ol poprhyric glassy basalt similar to 10-01 but tabular, either a sheet flow or the outer thick crust of a pillow . |
ISMAR-UR-SGS-SCU |
|
DR10-04 |
BAS |
14x10x4 |
same as 10-03 |
ISMAR-UR-SGS-SCU |
|
DR10-05 |
BAS |
8x6x5 |
same as 10-01 |
ISMAR-UR |
|
DR10-06 |
BAS |
7x4x4 |
same as 10-01 |
ISMAR-UR |
|
DR10-07 |
BAS |
6x6x1.5 |
same as 10-03 |
ISMAR-UR |
|
DR10-08 |
CCR |
various size |
|
ISMAR-UR-SGS |
|
DR11-01 |
VS(?) |
very small fragments |
|
ISMAR |
|
DR11-02 |
CCR |
various size |
|
ISMAR-UR-SGS |
|
Next: MAGNETOMETRY
Up: INITIAL RESULTS
Previous: BATHYMETRY
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2005-11-05