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Geology--Wyoming--Bear Lodge Mountains; Igneous rocks--Wyoming--Bear Lodge Mountains; Alkalic igneous rocks; Carbonatites--Wyoming--Bear Lodge Mountains
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Tertiary Alkalic Igneous Activity, Potassic Fenitization, Carbonatitic Magmatism, And Hydrothermal Activity In The Central And Southeastern Bear Lodge Mountains, Crook County, Wyoming, Gordon A. Jenner
Theses and Dissertations
The Bear Lodge Mountains are located in Crook County in north eastern Wyoming. The core of the uplift consists of alkalic igneous rocks that range from Early to Late Eocene in age. A petrologic and geochemical study of surface and subsurface samples from the southeastern and central portions of the core reveals a complex history of multiple alkalic igneous events, potassic metasomatism, carbonatitic magmatism, and hydrothermal alteration.
An early episode of alkalic igneous activity is represented by latite and trachyte porphyries, phonolite and trachyte porphyries, and natrolite-garnet syenites and malignites. Throughout much of the complex, the composition of these older …