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GEOREF RECORD

An Upper Cretaceous paleodrainage system on the Coastal Plain unconformity of Alabama-Georgia

Clinton Barineau and Diana Ortega-Ariza
An Upper Cretaceous paleodrainage system on the Coastal Plain unconformity of Alabama-Georgia (in Field excursions from the 2021 GSA section meetings, Joan Florsheim (editor), Christian Koeberl (editor), Matthew P. McKay (editor) and Nancy Riggs (editor))
Field Guide (Geological Society of America) (September 2021) 61: 35-60

Abstract

Rocks of the Upper Cretaceous Tuscaloosa Formation (Cenomanian) and Eutaw Formation (Santonian) in southwestern Georgia and southeastern Alabama record an interval of fluvial and nearshore marine deposition. In the vicinity of Columbus, Georgia, basal units of the Tuscaloosa Formation consist of a residual paleosol built on crystalline rocks of the Appalachian Piedmont covered by conglomeratic sandstones deposited in braided stream systems flowing across the mid-Cenomanian Coastal Plain unconformity. The unconformity, which separates Cretaceous detrital rocks from underlying metamorphic rocks and residual paleosols built on those metamorphic rocks, lies primarily within the Tuscaloosa Formation in this region and is marked at the modern surface by the geomorphic Fall Line. Mapping of the unconformity across the region reveals areas of significant paleorelief associated with a number of distinct paleovalleys incised into the mid-Cenomanian surface. The most distinct of these lie immediately east of the Alabama-Georgia state line, within 15 km of the modern Lower Chattahoochee River Valley. Spatially, these distinct paleovalleys lie immediately north of a Santonian estuarine environment recorded in the Eutaw Formation, disconformably above the Tuscaloosa Formation. Collectively, paleo-valleys in the mid-Cenomanian surface, the fluvial nature of the Tuscaloosa Formation in southwestern Georgia and southeastern Alabama, and the estuarine environment in the younger Eutaw Formation suggest a persistent ( approximately 10 m.y.) paleodrainage system that may be a forerunner to the modern Chattahoochee River.


ISSN: 2333-0937
EISSN: 2333-0945
Serial Title: Field Guide (Geological Society of America)
Serial Volume: 61
Title: An Upper Cretaceous paleodrainage system on the Coastal Plain unconformity of Alabama-Georgia
Title: Field excursions from the 2021 GSA section meetings
Author(s): Barineau, ClintonOrtega-Ariza, Diana
Author(s): Florsheim, Joaneditor
Author(s): Koeberl, Christianeditor
Author(s): McKay, Matthew P.editor
Author(s): Riggs, Nancyeditor
Affiliation: Columbus State University, Department of Earth and Space Sciences, Columbus, GA, United States
Affiliation: University of California at Santa Barbara, Earth Research Institute, Santa Barbara, CA, United States
Pages: 35-60
Published: 20210924
Text Language: English
Publisher: Geological Society of America, Boulder, CO, United States
ISBN: 9780813756615
References: 59
Accession Number: 2023-002970
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols., geol. sketch maps, sects.
N32°19'60" - N32°40'00", W85°55'60" - W85°12'00"
Secondary Affiliation: University of Kansas, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2023, American Geosciences Institute.
Update Code: 202303
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