About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 57 (1973)

Issue: 4. (April)

First Page: 812

Last Page: 812

Title: Carbonate Petrology of Green River Formation (Eocene), Uinta Basin, Utah: ABSTRACT

Author(s): Charles R. Williamson, M. Dane Picard

Article Type: Meeting abstract


The Green River Formation contains a diverse suite of lacustrine carbonate rocks comparable to that of carbonate formations of marine origin. Fossils (calcareous algae, ostracodes, gastropods, pelecypods), coated grains, microcrystalline carbonate aggregates, sparry carbonate, microcrystalline carbonate, and terrigenous grains are the main rock-forming components of the lacustrine carbonates. The most abundant allo-chemical constituents are polygenetic microcrystalline carbonate aggregates (intraclasts, pelletoids) and fragmental algal "plates." Coated grains (ooliths, pisoliths, circumcrusts) are less common and probably are biochemical (algal?) precipitates. Microcrystalline carbonate is the most abundant orthochemical constituent, but neomorphic and pore-filling sparry calcite are present. Dolomicrite is ubiquitous and probably formed as a replacement product of calcium carbonate before lithification. Terrigenous constituents are present in nearly all carbonate rocks; they constitute as much as 50% of some carbonates. The similarity of lacustrine and marine carbonate rocks indicates that the 2 types can not be differentiated solely on the basis of petrographic relations.

Sedimentary structures, stratification, color, and lithologic associations and variations within the Green River Formation indicate that the carbonates were deposited in a wide range of lacustrine environments. Recognized depositional environments include mudflat, lagoonal, shoal, reef, and offshore.

Preliminary ^dgr 18O and ^dgr 13C analyses of carbonate rocks from the Green River Formation indicate a biogenic fractionation for the microcrystalline carbonate of ooliths, pisoliths, and certain microcrystalline carbonate aggregates, and an early diagenetic replacement origin for dolomicrite.

End_of_Article - Last_Page 812------------

Copyright 1997 American Association of Petroleum Geologists