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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 50 (1966)

Issue: 3. (March)

First Page: 645

Last Page: 646

Title: Textural Trends of Recent Sediments from River to Abyssal Plain off Oregon: ABSTRACT

Author(s): John V. Byrne, L. D. Kulm, Neil J. Maloney

Article Type: Meeting abstract

Abstract:

Recent sediments from river to abyssal plain in the area of the central Oregon coast show distinct textural trends. Textural parameters were computed for more than 300 sediment samples from Yaquina River, Yaquina Bay, neighboring coastal beaches and dunes, and from the continental shelf, slope, and abyssal plain off Yaquina Bay.

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Yaquina River sediments are poorly to well sorted, angular to subangular, and range in grain-size from silt to coarse sand. Sediments within the bay range in size from silt to medium-grained sand, are angular to subangular, and are poorly to well sorted. Beaches and dunes consist of well-sorted fine sand. Well-sorted, fine detrital sand covers the inner continental shelf (0-50 fms.), and grades laterally into poorly-sorted, glauconite-rich, clayey silt on the outer shelf (50-100 fms.). Clayey silt with small amounts of Foraminifera, radiolarians, diatoms, and sponge spicules covers the continental slope. Silty clay is predominant at the base of the slope of the abyssal plain (1,500 fms.).

From an areal standpoint, the beach, dune, and inner-shelf sediments are more uniform than those of the river, bay, outer shelf, and upper slope. Beach and dune sediments are best sorted. Within the bay, sorting is better toward the coast line. Most river and bay sediments are positively skewed; beach and dune sands mainly are negatively skewed. Offshore, the median diameter generally decreases with depth, and sorting becomes poorer. Skewness is negative for the inner-shelf sediments, positive for the deposits of the outer shelf and continental slope, and negative for abyssal-plain sediments.

Similarities of texture and fauna of Recent sediments with those of middle and late Tertiary rocks in the area indicate that comparable textural trends existed.

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Copyright 1997 American Association of Petroleum Geologists