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Perspectives on he paleolimnology of the late Eocene Florissant Lake from diatom and sedimentary evidence at Clare's Quarry, Teller County, Colorado, USA

Mary Ellen Benson, Dena M. Smith and Sarah A. Spaulding
Perspectives on he paleolimnology of the late Eocene Florissant Lake from diatom and sedimentary evidence at Clare's Quarry, Teller County, Colorado, USA (in From saline to freshwater; the diversity of western lakes in space and time, Scott W. Starratt (editor) and Michael R. Rosen (editor))
Special Paper - Geological Society of America (December 2019) 536

Abstract

The late Eocene Florissant Formation in central Colorado is a rich and diverse continental Lagerstatte yielding well-preserved fossil assemblages from lacustrine and fluvial facies. This investigation focused on the lacustrine facies at Clare's Quarry and used biotic and abiotic evidence to characterize aspects of the lake and processes that resulted in the accumulation and preservation of the host rock and its fossils. Autecology of modern analogs representing the fossil diatom taxa was used to augment sedimentary data in characterizing the lake, propose peripheral habitats within the catchment area, and suggest a terrestrial source for mudstone units. The sedimentary and stratigraphic record at the study site reveals a lake with sufficient depth to allow bottom waters to remain isolated and anoxic for long periods. Sediments that accumulated in the lake produced distinct lacustrine lithofacies that are interpreted as representing at least three modes of origin: stable lake, pyroclastic, and mud turbidite sedimentation. Slow, suspension settling of fine clays and volcanic ash into a moderately deep, stable lake resulted in laminated shales. These laminated shales contain frustules of diatoms from planktic and benthic lake habitats; diatoms transported into the lake from streams and wetlands; fish, mollusks, ostracods, and insects; and plants from marginal and upslope environments. Intermittent volcanic eruptions produced air-fall ash and granular tuff that accumulated as interbeds within the lake shales. Periods of stable lake sedimentation were frequently interrupted by rapid influxes of suspended fine clays, perhaps as mud-dominated turbidites that prograded into the lake at intervals of high runoff triggered by climatic, volcanic, or tectonic events.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 536
Title: Perspectives on he paleolimnology of the late Eocene Florissant Lake from diatom and sedimentary evidence at Clare's Quarry, Teller County, Colorado, USA
Title: From saline to freshwater; the diversity of western lakes in space and time
Author(s): Benson, Mary EllenSmith, Dena M.Spaulding, Sarah A.
Author(s): Starratt, Scott W.editor
Author(s): Rosen, Michael R.editor
Affiliation: U. S. Geological Survey, Geology, Geophysics, and Geochemistry Science Center, Denver, CO, United States
Affiliation: U. S. Geological Survey, Menlo Park, CA, United States
Published: 20191231
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 9780813795362
References: 49
Accession Number: 2020-010992
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. col., 2 tables, geol. sketch maps
N38°55'60" - N38°55'60", W105°16'60" - W105°16'60"
Secondary Affiliation: National Science Foundation, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute.
Update Code: 202008
Program Name: USGSOPNon-USGS publications with USGS authors
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