INITIAL RESULTS

We arrived in the operation area 15-mar-1996, and realized soon that our workplan should have been reorganized. 17-Mar we met the first of a long series of icebergs. This was a very bad surprise, since during previous expedition we had only one detection, at the end of survey. Some of the icebergs had so small relief to be undetectable by radar, expecially during rough seas (almost 70-80% of cruise). The decision was taken to reduce speed during night to a maximum of 5 Kn.

After having investigated part of the Conrad F.Z. and SW part of BTJ, we decided to go to the Shona Smt., since we were contrasting a very strong storm from NW and were forced to drift straight there. After having obtained bathymetric maps, rock samples and one Heat Flow on the top, we moved toward MAR with the aim to trace the axial valley and have some detailed bathymetric maps for dredging. We crossed MAR on 3 transects with good magnetic, bathymetric and gravimetric data. Between Shona Smt. and MAR we had a second Heat Flow Station, with the recovery of a very interesting core.

When we reached our 1994 survey area we did two additional lines west of it. Finally, we went to northern area of Bouvet F.Z. where we started a NE-SW survey. On Spiess Smt. we interrupted the long offset lines, starting a more detailed survey on the shallower part of the seamount. During this period we occupied several dredging stations, partly originally planned while other were decided upon the results of swath-bathymetry data processing.

Toward the end of the cruise, on the southern area of Bouvet F.Z. we had very rough weather, with a severe storm that stopped all the operations for 3 days. During this stand by the ship drifted North for more than 120 miles and we decided to go to survey on MAR. We performed additional multibeam and magnetics lines, and occupied three dredging stations on the rift valley. On 23-apr-1996 ship left the operation area, with heading to Abidjian. Additional magnetometric and multibeam data were collected during transit.

A total of 5600 Nm of Multibeam and Magnetic lines were run. A total of 26 dredging stations were occupied, 22 of them recovered samples, one was lost. Glasses were collected in 18 dredges. In all dredges but ones in the areas of neo-volcanic activity glacial erratics were present, reaching up to 30-50% of materials.

From geophysical lines we obtained detailed morphobathymetric and magnetic images of the area. Gravity data +have to be reduced after calibration, and we believe to be able to make good analysis of high frequency anomalies.

Three types of basalt associations were recovered :

1. fresh, highly vesicular aphyric and Cpx-Ol-Pl-phyric basalts,
2. sligthly altered Cpx-Ol-Pl phyric and aphyric basalts, covered by Fe-Mn crust (3 to 20 mm),
3. hydrothermally altered (with chlorite, calcite, quartz, sulphides, etc.) sometimes tectonized aphyric basalts.

Heat flow data (4 stations) ranged from 50 to 300 mW/m$^2$.

Initial results are presented for the different study areas, in order to address the importance of the preliminary findings and processing sequence of the data acquired.

The sample descriptions can be found in Tab.7.

Table 7: Sample positions.

ID	MONITORING SITE	DESCRIPTION	COMMENTS
G9623	NE slope of high S of W end of Bouvet F.Z.	Fe-Mn crust 2 cm; little glassy basalt	NULL
G9622	S slope of high S of W end of Bouvet F.Z.	basalt with 0;5 cm Fe-Mn crust	NULL
G9621	S wall of the E-W basin; 30 miles S of Spiess ridge	fresh and different alteration rate basalts; thick Fe-Mn crust	NULL
G9620	N wall of the E-W basin; 30 miles S of Spiess ridge	pillow fragments with thick Fe-Mn crust; fresh vesicular basalts; interesting big vitrobasalt sample; sandstone in situ; erratics	NULL
G9619	little high SW of Spiess ridge	basaltic breccia; including glass; with thick Fe-Mn crust; up to 2 cm; small basaltic samples	NULL
G9618	S slope little high; E of Spiess ridge	basalts and fresh glasses with thin Fe-Mn coating	NULL
G9617	E-W deep slope NE of Spiess ridge	pillow fragments with fresh glass; tectonized basalts; different degrees of hydrotermal alteration; Fe-Mn patina; sulphides	NULL
G9616	S slope of high NE of Spiess ridge	pillow fragments basalts with thick Fe-Mn crust; high vesicular fresh basalts with thin Fe-Mn patina	NULL
G9615	top of little high; N of Spiess; place of highest magnetic anomaly	fresh pillow fragments; high fluidal cord lavas with thin glassy crust; fresh glasses; thin Fe-Mn coating	we decide to pass trough caldera during dredge; so the ending depth is bigger then the starting depth
G9613	S slope of caldera	pillow fragments and flow lavas with glassy crust; fresh glass; 1 mm max Fe-Mn coating	NULL
G9614	N slope of high SW of Spiess ridge	big pillow fragments; basaltic breccia; lavas with thin glassy crust; lightly altered	NULL
G9612	S slope of caldera	fresh high vesicular basalt; flow lavas with Pahoe-hoe structures; big amount of fresh glass	NULL
G9611	NW wall inside caldera of Spiess ridge	pillow basalt with thin Fe-Mn crust; vesicular basalts; glassy crusts; Fe-hydroxide alteration	NULL
G9610	N slope of high SW of Spiess ridge	olivine basalt 85%	vesicular lavas 10%; one big sample (50 kg) of olivine tholeite
G9609	N slope of high; SE of Shona seamount	basalts 60%	30
G9608	NE slope; top of Shona seamount	basalts 60%	glacial erratics 10%
G9607	SW wall of the oblique basin; (Axial valley)	lost	lost
G9606	NW wall of the oblique basin; (Axial valley)	empty	empty
G9605	high inside corner; S slope	one sample of basaltic breccia	NULL
G9603	high inside corner; W top	empty	empty
G9604	high inside corner; N slope of W top	peridotites 30%	calcarenites 30%
G9601	high inside corner; S slope near nodal basin	empty	empty
G9602	high inside corner; S slope	basalts 80%	gabbro 5%
G9624	M.A.R.	fresh pillow basalt sectors; with glassy crust; no erratics; no Fe-Mn crust; abundant fresh glasses	NULL
G9625	M.A.R.	1 pillow fragment; little basalts with glass; thin Fe-Mn patina	NULL
G9626	M.A.R.	One big very fresh lava burr; Cpx-Ol-Pl porphyric; with thick glassy crust and fragments of glassy crust	NULL