A TURBIDITE SERIES IN THE CRESCENT FORMATION, OLYMPIC PENINSULA, WA
BEAULIEU, Elizabeth, Geology Dept, Univ. of Puget Sound, Univ of Puget Sound, Tacoma, WA 98416, lizbeaulieu@hotmail.com and CLARK, Kenneth, geology, Univ of Puget Sound, Tacoma, WA 98406

A series of turbidites composed of alternating fine sand and silt layers are present in an 84 m section on the Olympic Peninsula, WA. The sedimentary sequence is interbedded within the predominantly basaltic 15-km thick Crescent formation. Lab analyses with pretrographic thin sections and the SEM reveal fine, angular to sub-angular constituent grains of clinopyroxene, plagioclase, porphyritic basalt and chlorite. The absence of quartz and micas, which would otherwise indicate a continental source for the sediment, suggests deposition as a submarine fan from an offshore volcaniclastic origin isolated from continents. The alternating strata, with an average of 2 cm a bed, can be classified as facies c and facies d (Mutti & Ricchi Lucchi, 1971). The facies classification is probable representation of the middle to outer fan. This turbidite sequence is on strike with a similar deposit located 11 km away and may be part of the same submarine source.

Cordilleran Section - 98th Annual Meeting (May 13–15, 2002)
Session No. 16--Booth# 8
Architecture of Cascadia: A Synthesis of New Geologic and Geophysical Mapping in the Forearc (Posters)
LaSells Stewart Center: Agriculture
8:00 AM-12:00 PM, Tuesday, May 14, 2002
 

© Copyright 2002 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.