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GEOREF RECORD

A Lower Ordovician sponge/algal facies in the Southern United States and its counterparts elsewhere in North America

Leonard Alberstadt and John E. Repetski
A Lower Ordovician sponge/algal facies in the Southern United States and its counterparts elsewhere in North America
Palaios (June 1989) 4 (3): 225-247

Abstract

Subsurface Ordovician rocks in the Black Warrior Basin, Mississippi Embayment, and the eastern part of the Arkoma Basin reflect a different depositional history than coeval rocks exposed in the Nashville Basin, Ozark Dome, and southern Appalachians. The succession consists of four infonnallithologic units. From top to bottom these are: 1) "Stones River'' limestones, 2) upper dolostone, 3) sponge/alga/limestones characterized by the presence of Nuia, a'nd 4) lower dolostone. Of these, the sponge/ algal limestone unit is the most atypical. It has a conspicuous biotic assemblage which can be recognized petrographically in well cuttings. The diagnostic fossil allochems are: sponges, sponge spicules, Nuia, Girvanella, and Sphaerocodiwn. Conodonts from the sponge/algal limestones are probably entirely Early Ordovician (Canadian) and include cold- and deep-water species found in theN orlh Atlantic Province, whereas those in the overlying dolostones represent exclusively warmwater, shelf environments. The conodonts in the Black Warrior Basin suggest that an unconformity between Lower and Middle Ordovician carbonates (Knox unconformity) does not exist in much of that region. The sponge/ algal limestones represent a different facies than their coeval shelf rocks in the interior of the continent. The limestone contains a distinctive biotic assemblage recognized in Lower Ordovician rocks in Newfoundland, in the Arbuckle and Wichita mountains of Oklahoma, in West Texas, and in the Great Basin of Nevada and Utah. During Early Ordovician time these sponge/algal assemblages lived in open, nonnal marine, slightly deeper water on shelves or ramps on the outer parts of the continent, in some places fronting deep basinal environments. In its edge-of-continent position it resembles the distribution of the olenid trilobite faunas and the Toquima trilobite realm. However, unlike those occurrences, the sponge! algal facies has not been fully documented on other continents although there is increasing evidence that it is present.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 4
Serial Issue: 3
Title: A Lower Ordovician sponge/algal facies in the Southern United States and its counterparts elsewhere in North America
Affiliation: Vanderbilt Univ., Geol. Dep., Nashville, TN, United States
Pages: 225-247
Published: 198906
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 50
Accession Number: 1989-064986
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch maps
N29°00'00" - N39°00'00", W94°30'00" - W81°40'00"
Secondary Affiliation: U. S. Geol. Surv., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1989
Program Name: USGSOPNon-USGS publications with USGS authors
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