Site 766: Sediment Lithostratigraphy

Proceedings of the Ocean Drilling Program: Initial Reports
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Abstract

A total of 466.7 m of Pleistocene to upper Valanginian sediments were rotary cored at Site 766 (Fig. 10). Average recovery was 63.1%. Recovery was less than 50% in the following cores: Cores 123-766A-3R, -8R, -10R, -12R, -13R, -21R to -27R, -31R, and 123-766A-33R to -39R. Fourteen of the 20 cores having poor recovery occur in two intervals of seven cores each. Both of these intervals are lithologically distinct, and poor recovery is attributed to the occurrence of specific lithologies that are not easily recovered: the interval from Cores 123-766A-21R to 123 766A-27R contains hard cherty layers interlaminated with softer sediments; the interval from Cores 123-766A-33R to 123-766A 39R contains fine to medium-grained, poorly consolidated sandstones. Extremely soft nannofossil oozes in Cores 123 766A-1R through -10R were highly disturbed by drilling, but there is no evidence that any visible structure originally existed in these sediments. Firmer sediments below Core 123-766A-9R were highly disturbed only locally. The sedimentary sequence is divided into three units and eight subunits. The unit and sub unit boundaries largely coincide with boundaries between seis mic units, magnetic susceptibility units, and biostratigraphic units (Fig. 10). The basal sediments in Core 123-766A-49R are interbedded with igneous intervals interpreted as sills.

Publication type Article
Publication Subtype Journal Article
Title Site 766: Sediment Lithostratigraphy
Series title Proceedings of the Ocean Drilling Program: Initial Reports
DOI 10.2973/odp.proc.ir.123.105.1990
Volume 123
Year Published 1990
Language English
Publisher Texas A&M University Ocean Drilling Program
Contributing office(s) Alaska Science Center
Description 10 p.
First page 276
Last page 285
Other Geospatial Argo Abyssal Plain
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