The palynoflora of the Fossil Butte Member of Green River Formation was studied to enhance our understanding of the depositional environment of ancient Fossil Lake. Forty-nine outcrop samples were collected from three measured sections representing the center, the margin, and intermediate areas of Fossil Lake. Of the 49 samples, 12 yielded a fairly well preserved palynomorph assemblage.
A late early Eocene to early middle Eocene age for the Fossil Butte palynoflora is indicated by the presence of Bombacaceae, Eucommia, Ilex, Juglans, Pistillipollenites, Platycarya, Pterocarya, Tilia, and Taxodium. Additional evidence for the early to middle Eocene age of the Fossil Butte Member was from a potassium-argon age determination of a potassium-feldspar tuff of 49.1 ± 1.8 m.y. These data indicate that the major portion of the Fossil Butte Member was contemporaneous with the deposition of the Wilkins Peak Member in the Green River Basin.
Evidence from the palynoflora suggests that the climate during deposition of the Fossil Butte Member was in transition between a humid, subtropical and a cooler, drier, warm temperate one with moderate fluctuations during various episodes of deposition.
Other evidence from the palynoflora indicates that moist lowlands and floodplains existed around Fossil Lake with upland forests on the surrounding ridges and mountains. Streams originating in the highlands supplied water for Fossil Lake and the surrounding vegetation.
Kerogen analysis of rocks from the Fossil Butte Member showed no correlation between the kerogen type and either the lithology or preservation of palynomorphs.
H. Paul Buchheim
Lanny H. Fisk
Knut A. Andersson
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Pollen; Fossil; Palynology -- Wyoming
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Cushman, Robert A. Jr., "Palynology and Paleoecology of the Fossil Butte Member of the Eocene Green River Formation in Fossil Basin, Lincoln County, Wyoming" (1983). Loma Linda University Electronic Theses, Dissertations & Projects. 1035.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives