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Paragenesis Of Lacustrine Microbialites In The Upper Wilkins Peak Member, Green River Formation, Wyoming, Bethania Chagas Tosta Siviero

Loma Linda University Electronic Theses, Dissertations & Projects

Microbialites from the upper Wilkins Peak Member were investigated to determine their paragenesis and to help interpret lake chemistry. Two specific microbialite beds were analyzed that are associated with the “layered tuff”. Samples were collected from correlated sections along a NW to SE, 24 km line of section from lake margin towards lake center. XRD, SEM/EDS, and petrographic analysis show differences in diagenesis above and below the layered tuff.

Microbialites below the tuff bed contain some primary calcite with diagenetic dolomite and abundant secondary silicification. Later, dolomite replaces both calcite and quartz. Pores are commonly filled with 20 μm euhedral …