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Sedimentology, Sedimentary Petrology, And Tectonic Setting Of The Lower Miocene Clallam Formation, Northern Olympic Peninsula, Washington, Kurt Soe Anderson

WWU Graduate School Collection

The Lower Miocene Clallam Formation, located on the northern coast of the Olympic Peninsula, Washington, is an approximately 800 m thick sequence of sandstone and conglomerate that was deposited in the predominantly marine portion of a prograding delta.

As a whole, the Clallam Formation coarsens and shallows upward, progressing from fossiliferous sandstones deposited below wave base, through storm-dominated deposits characterized by climbing ripples, graded rythmites, and hummocky cross-stratification, to coarse-grained distributary mouth deposits. Within this general progression are several small-scale coarsening- and shallowing-upward cycles that reflect the occupation and subsequent abandonment of distributary channels.

Analysis of lithic and monocrystalline grain …