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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 53 (1969)

Issue: 2. (February)

First Page: 463

Last Page: 463

Title: Sediment-Foraminiferal Relations within Inner Sublittoral Zone off Coast of Washington: ABSTRACT

Author(s): Ronald J. Echols, Sarah S. Barnes, Robert A. Harman

Article Type: Meeting abstract

Abstract:

Foraminiferal assemblages of the inner sublittoral zone (0-60 m) have been studied along the entire Pacific coast of the state of Washington and of northernmost Oregon. A substrate of fine sand having a mean diameter of 2.8-3.5 phi is prevalent, but relict gravel bars are seaward from the mouths of Grays Harbor and the Quinault River, and pockets of silt are present in the southern half of the area.

Regardless of sediment grain size, concentrations of Foraminifera increase seaward from less than one per gram of sediment to 10-25 per gram of sediment, and the percentage of arenaceous tests in foraminiferal assemblages increases seaward from less than 10 percent to more than 50 percent, except near the mouths of the Columbia River and Grays Harbor where dominantly arenaceous assemblages occur nearshore. The Previous HitdominantNext Hit arenaceous species generally is Eggerella advena; the Previous HitdominantNext Hit nearshore calcareous species generally is Buliminella elegantissima, except adjacent to rocky coastlines where Elphidium spp. dominates.

High relative Previous HitfrequenciesNext Hit of Trochammina charlottensis and Cribrostomoides jeffreysii are found only in the area of the gravel bars and high relative Previous HitfrequenciesNext Hit of Cibicides lobatulus and Glabratella ornatissima only in the area of nearshore rocky substrates. The general correspondence between occurrences of these species and a geographically restricted substrate is marked, but high relative Previous HitfrequenciesTop of these species (probably representing displaced tests) may occur in sand or silt sediments near the gravel or rock exposures.

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