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Pacific NW Geologic Mapping Project

Geologic maps of the North Cascades

Tcai-1. View north across Berdeen Lake [MBse] to Mount Blum, which is carved from tonalite of Chilliwack batholith (Index family, Tcai, of the Cascade Magmatic Arc) that here intrudes Darrington Phyllite (Ked) of the Northwest Cascade System. Glacial deposits (Qga) are predominently locally derived, but valley was overridden by the Cordilleran Ice Sheet. Photographed 1986. View image with annotation
Other photos that show unit Tcai:

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