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Pacific NW Geologic Mapping Project

Geologic maps of the North Cascades

Tcas-1. View to northeast from Summit Chief Mountain [SKse]. The Miocene Snoqualmie batholith (of the Snoqualmie family, Tcas) exposed on Mount Hinman has thermally metamorphosed Lower Eocene Swauk Formation (early extensional sedimentary rocks, Tees), which forms resistant crags of Bears Breast Mountain, and the Silver Pass Volcanic Member (Teev), which forms Summit Chief in foreground. Oligocene volcanic rocks of the Ohanepecosh episode (Tcao) forming Mount Daniel have also been recrystallized by heat from the nearby batholith. Contact dashed where approximately located. View image with annotation
Other photos that show unit Tcas:

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Photo Indices: Captions (Additional photos home) | Map | Young rocks and deposits | Older rocks west | Older rocks east