Desarrollo de la Antártica

Olav OrlJlún / NORWEGIAN ANTARCTIC RESEARCH, PAST AND PRESENT T'WD tide gages recording at the same time intervals were placed in the same area. !Detailed studies of potentially supercooled water were done at the edge of the Fildhner ice shelf. The marine geophysic programme was done by a four-man group from two institutions. Magnetometry was done throughout most oi the cruise, covering about 2,000 km within the Weddell Sea area and even longer distances during the crossing to and from Antarctica. Gravimetry was done o'll all track lines shown except the most easterly, as there was instrument failure at that time. Bathymetry soundings, to 6,000 m, were also done all the time apart from the most easterly tracOC. Seismic studies were done by two techniques. About 1,100 km were covered by reflection and refraction studies, using airguns as tlhe energy source, a 1.5 km long sixteen-channel streamer, sonar buoys, and a DFS-5 instrument. Signals were obtained down to about 6 km depth. Reflection studies Df about 1,200 km lenght were done with a sparker as energy source, these gave reflections down to aboul 500 m deptl1. TD study the sea bed conditions a side-seeking sonar was used over about 220 km, with results obtained down tD 400 m water depth. These showed hi~hly variable bottom topography. The combined cruise lines of the seismic and sonar studies are shown in Fig. 1 under the heading "geopíhysical studies". The geologic programme consisted of sampling at 27 localities, both dredging and coring, and at7 of these bottom phDtography was also obtained. Most oI the geologic stations are shown in Fig. 1. .Numerous types of bottom fauna were alsD Dbtained together with the geologic samples. The marine biologic programme was mostly a biochemic and bacteriologic study of krill, and of the processes of its decomposition. Krill samples were collected (Fig. 1) and in part frozen and in part allowed to deteriorate and studied at various time intervals. A two– man group conducted these studies, and they also took general hiologic registrations of animal life encountered. The sea ice studies and tihe ice shelf studies were doue by one man, the main programme being a general registration of the sea ice conditions, to be used as ground control for the satellite sensed information, and a study of the ice shelf thickness and position, to determine mass outHow rates far this part of Antarctica. Both this mapping programme, and the various Dúher shipboard programmes were dependent upon precise position information. To 159