Sedimentologic and biostratigraphic implications for early Eocene lacustrine systems, eastern Great Basin, Nevada

Conference · Thu Apr 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5341962

Dubiel, R F; Potter, C J; Snee, L W ^[1]; Good, S C ^[2]

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1. Geological Survey, Denver, CO (United States)
2. State Univ. Coll., Cortland, NY (United States)

A multidisciplinary study integrating sedimentology, molluscan paleontology and paleoecology, structural and geologic mapping, and [sup 40]Ar/[sup 39]Ar dating of volcanic flows indicates the White Sage Formation north of the Deep Creek Range on the NV-UT border was deposited during the early Eocene in marginal-lacustrine, lacustrine, freshwater-marsh, and minor terrestrial settings. Sedimentary facies include wave-reworked, locally derived Paleozoic carbonate-clast basal conglomerates in contact with bedrock; carbonate tufa mounds; organic-rich mudstones; and laminated to medium-bedded carbonates. The wave-reworked conglomerate implies a broad lake with considerable fetch to generate large waves, but one with only small drainage basins with sharp relief to supply the locally-derived clasts. There is a striking lack of any fluvial, deltaic, or alluvial-fan deposits that would indicate development of substantial drainage areas. The large tufa mounds indicate a high-wave-energy shoaling environment with stable substrate and topography. The profusion of lacustrine carbonates indicates dominantly chemical- or biochemical-induced deposition in a carbonate-saturated lake. The aquatic molluscan fauna indicates shallow, quiet lacustrine conditions with emergent vegetation. The limpets inhabited areas of rooted aquatic vegetation, and the terrestrial gastropods indicate marshes adjacent to the lacustrine system. The molluscan assemblage constrains the age of the White Sage as early Eocene, indicating a lacustrine system equivalent to the Sheep Pass Formation and to outcrops near Illipah, NV that have similar facies and molluscan faunas and that also lack significant fluvial, deltaic, or alluvial fan deposits. The data are consistent with a model wherein the White Sage, Sheep Pass, and Illipah carbonates were deposited in a large lake superimposed on preexisting topography with low relief and little or no syndepositional extension.

• OSTI ID: 5341962
• Report Number(s): CONF-9305259-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CARBONATE ROCKS
PALEONTOLOGY
STRATIGRAPHY
GEOLOGIC FORMATIONS
NEVADA
ARGON 39
ARGON 40
CONGLOMERATES
EOCENE EPOCH
FOSSILS
GREAT BASIN
ISOTOPE DATING
ISOTOPE RATIO
LAKES
MOLLUSCS
VOLCANIC ROCKS
AGE ESTIMATION
ANIMALS
AQUATIC ORGANISMS
ARGON ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CENOZOIC ERA
DEVELOPED COUNTRIES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
GEOLOGY
IGNEOUS ROCKS
INVERTEBRATES
ISOTOPES
LIGHT NUCLEI
NORTH AMERICA
NUCLEI
RADIOISOTOPES
ROCKS
SEDIMENTARY ROCKS
STABLE ISOTOPES
SURFACE WATERS
TERTIARY PERIOD
USA
YEARS LIVING RADIOISOTOPES
580000* - Geosciences