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Stratigraphy, Structure, And Petrology Of The Snoqualmie Pass Area, Washington, Lawrence A. Chitwood
Stratigraphy, Structure, And Petrology Of The Snoqualmie Pass Area, Washington, Lawrence A. Chitwood
Dissertations and Theses
The Snoqualmie pass area lies about 50 mi (80 km) east of Seattle, Washington, along the crest of the Cascade Range. Five stratified units, forming a composite section over 22,000 ft (6700 m) thick, are recognized in the area. They were deformed and later intruded by granodiorite and quartz monzonite porphyry of the Snoqualmie batholith (middle Miocene). The oldest unit, the Denny Formation (Permian), 7000 ft (2100 m) thick, consists of interstratified basalt, andesite and dacite volcanic rocks and limestone and chert beds. This formation is unconformably overlain by a thick conformable sequence of early Tertiary strata which are subdivided, …