AREAL AND VERTICAL VARIATION OF HEAVY MINERAL COMPOSITION OF THE SURFACE SEDIMENTS, ROSS SEA, ANTARCTICA

• Main Authors: トクハシ シュウイチ, / ニシムラ アキラ, Shuichi TOKUHASHI, Christopher M. AGYINGI, Akira NISHIMURA
• Format: Report
• Language: English
• Published: Geological Survey of Japan 1996
• Subjects: Antarctica; Ross Sea; glacial marine sediments; heavy mineral analysis; ice-raft; Antarctic; East Antarctica; West Antarctica; Victoria Land; Antarc*; Iceberg*
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2829; http://id.nii.ac.jp/1291/00002829/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2829&item_no=1&attribute_id=18&file_no=1

In this paper are shown the results of heavy mineral analysis of ice-rafted sand fractions of muddy sediments from several gravity cores around the Ross Sea collected during the TH91 and TH92 Antarctic research cruises by the Technology Research Center, Japan National Oil Corporation, using the R/V HAKUREI-MARU. Samples for the analysis were collected from two levels of the cores, i.e. late Holocene S-group samples in the upper part and last glacial to early Holocene D-group samples in the lower part of the cores. Both the S-group and D-group samples are comprised of the same kinds of heavy minerals and show the nearly completely same distribution patterns of the frequency of those minerals. These patterns suggest the existence of at least two petrographic provinces, i.e. western and central-eastern areas, which must reflect the difference of the provenances of East Antarctica and West Antarctica. Especially, olivine and clinopyroxene with titanaugite, dominantly distributed in the western area, were probably supplied from the late Quaternary McMurdo alkaline basaltic volcanics fringing the eastern margin of the Victoria Land. The strong similarity of the distribution pattern of heavy mineral composition between the S-group and D-group samples suggests the long-term stability of flow patterns of icebergs in the Ross Sea. Such stability must be controlled by the submarine topography in the Ross Sea, which plays the most important role in the Ross Sea, controlling not only the types of sediments, but also the flow patterns of icebergs.