Physical Sciences and Mathematics Commons^™

Petrology And Mineralogy Of Tertiary Volcanic Rocks In The Vicinity Of The Rozel Hills And Black Mountain, Box Elder County, Utah, Elizabeth R. Greenman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two basalt flows and an andesite fissure eruption occur in the Rozel Hills - Black Mountain area in Box Elder County, Utah. Both basalt flows are aphanitic, and contain olivine, plagioclase, augite, and opaque oxides. They may be distinguished both chemically and on the basis of their textures. Unit 2 basalt is finer grained, and appears to be associated with a fault in the Black Mountain area. Chemically, it is similar to high-iron lavas in the Craters of the Moon, Idaho area. It has higher alkali, total iron, and titanium contents that Unit 1 basalt. Unit 1 basalt is similar …

Mineralogy And Petrology Of Lava Flows (Tertiary-Quaternary) In Southeastern Idaho And At Black Mountain, Rich County, Utah, Barbara J. Puchy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lava flows of Tertiary-Quaternary age occur in Enoch Valley, Upper Valley, and Slug Valley in southeastern Idaho. The basalts in Upper Valley and Enoch Valley contain olivine (Fo₆₉ to Fo₃₇), plagioclase (An₆₂ to An₃₉), augite and Fe-Ti oxides. The lava in Slug Valley lacks plagioclase, but contains sanidine (Or₇₀ to Or₅₆) with a trace of biotite and amphibole, and thus, has been termed alkali trachyte.

Black Mountain, on the eastern side of Bear Lake, northeastern Utah, is capped by basalt. Minerals present include olivine (Fo₈₃ to Fo₇₂), plagioclase …