A Turbidite Series In The Crescent Formation, Olympic Peninsula, Washington
Abstracts With Programs - Geological Society Of America
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.
Beaulieu, Elizabeth, and Kenneth P. Clark. 2002. "A turbidite series in the Crescent Formation, Olympic Peninsula, Washington." Abstracts With Programs - Geological Society Of America 34(5; 5): 32-32.