The Geologic History of Tamanowas Rock
Jeff Tepper, Chairman of the Geology Dept. at the University of Puget Sound in Tacoma, spoke about Tamanowas Rock, a sacred site for the Callam Tribe and local rock climbing site located just west of Chimacum. After the talk, Jeff and other geologists in the group led 105 Tamanowas enthusiasts on a walk from the Tri-Community Center to the rock where its geology and sacred status will be discussed.
Tamanowas Rock is an atypical volcanic rock that was emplaced by an eruption about 44 million years ago. This particular rock is an adakite, which occurs when hot mantle rises through a gap in a subducting tectonic plate and causes the edges of the plate to melt.