Sedimentology of the Argo and Gascoyne abyssal plains, NW Australia: Report on Ocean Drilling Program Leg 123 (Sept. 1–Nov. 1, 1988)

Carbonates and Evaporites
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Abstract

Ocean Drilling Program Leg 123 drilled two sites in the Indian Ocean in order to study the rifting and early spreading of one of the world’s oldest ocean basins.

Site 765 was drilled in 5714 meters of water on the Argo Abyssal Plain northwest of Australia. The sedimentary succession records the opening of an ocean basin, from the first sediments deposited atop young oceanic crust, to the present day. The oldest sediments are microlaminated brown silty claystones, locally rich in calcareous bioclasts. Most of the sequence is dominated by turbidites (primarily calcareous) which probably originated within canyons cut into the margin of the drowned platform of the North West Shelf of Australia.

Site 766 is located in 3998 meters of water, at the base of the steep western margin of the Exmouth Plateau. The oldest sediments penetrated are glauconitic, volcaniclastic, and bioclastic sandstones and siltstones, which are interbedded with inclined basaltic sills. These sediments were deposited by a prograding submarine fan system which shed shallow marine sediments westward or northwestward off of the western rim of the Exmouth Plateau. Sandstones are succeeded by silty claystones, recording gradual abandonment or redirection of the fan system. An overlying sequence of pelagic and hemipelagic clayey and zeolitic calcareous oozes and chalks is succeeded by featureless and homogeneous pelagic nannofossil oozes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Sedimentology of the Argo and Gascoyne abyssal plains, NW Australia: Report on Ocean Drilling Program Leg 123 (Sept. 1–Nov. 1, 1988)
Series title Carbonates and Evaporites
DOI 10.1007/BF03175117
Volume 3
Year Published 1988
Language English
Publisher Springer
Contributing office(s) Alaska Science Center
Description 12 p.
First page 201
Last page 212
Country Australia
Other Geospatial Argo abyssal plain, Gascoyne abyssal plain