Preliminary report of the marine geophysical and geological surveys off Wilkes Land, Antarctica in 1983-1984

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During the 1983-1984 Antarctic summer season, a multi-channel seismic reflection survey of 3700km along with geophysical and geological surveys was conducted in the Scott Basin lying in the offing of Wilkes Land. Conventionally processed data of the seismic sections (6-folds) revealed the following geological features. (1) The maximum sedimentary thickness was found to be approximately 3.75s in two-way reflection time under the abyssal plain. (2) The seismic section through DSDP site 268 indicated the distinct unconformity between Early Miocene and Pliocene. (3) The acoustic basement generally shows a gentle monoclinal slope in the continental shelf to the rise, while it shows remarkably complex relief under the abyssal plain. But the formations lying on the basement are almost flat. (4) A basement high extending from the southeast was observed in the eastern area, and anticlinal features on the time section were observed in the western area. Terrestrial heat flow measurements were taken at a total of nine sites, indicating between 1.3 and 1.6 HFU. They were almost the same as the world average of 1.5 HFU. A gravity core obtained from the basement high in the eastern area contained such warm-water planktonic foraminifera as Globorotalia inflata, G. praeinflata, and G. puncticuloides, suggesting the age of Late Pliocene-Early Pleistocene.
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