Soundings and Submarine Topography of the Glaciated Continental Shelf in Lutzow-Holm Bay, East Antarctica (Reports of the Japanese Antarctic Research Expedition)

Abstract

In the northeastern part of Lutzow-Holm Bay, there extends a continental shelf about 60 km wide. Bathymetric charts of the shelf were drawn, using numerous sounding data obtained by the icebreaker FUJI during the period of 1965-1970 and by the author in 1968. As a result of analyses of the charts, the author concluded on the geomorphology of the shelf as follows : 1) The shelf near Syowa Station is generally 100-200 meters deep. It becomes deeper gradually toward the offing and reaches to the depth of 350-400 meters at the outer margin of the shelf. 2) In the inner part of the shelf, there is a highly glaciated sea floor with low rises and broad troughs. One of the most striking features of this sea floor is linear arrangement of rises and troughs with two trends which are due to those of the schistosity and joint structures of bedrocks. 3) The bottom of the broad glacial troughs is about 400 meters deep near the coast and becomes shallower toward the offing, showing an undulating longitudinal profiles. Such troughs are recognized only in the inner part of the shelf at least 20 km off the coast. 4) Close to the coast, there are narrow channels deeper than the broad troughs. They are classified into two kinds ; one stretches longitudinally from the front of the present glaciers and another runs parallel to the coast. The latter seems to be controlled by rock structures, such as schistosity, whereas there is no evidence of recent tectonic movements related to their origin.