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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 933

Last Page: 933

Title: Mississippian Continental Margins of Conterminous United States: ABSTRACT

Author(s): Raymond C. Gutschick, Charles A. Sandberg

Article Type: Meeting abstract


The paleogeographic, paleotectonic, and paleobathymetric reconstruction of continental margins around the present western, southern, and eastern sides of the conterminous United States can be defined for a brief span (about 1.5 m.y.) of Mississippian time. Interpretations are made by applying a biostratigraphic and sedimentological model for the Deseret starved basin of Utah and Nevada to recently published shelf-margin studies. The time span is that of the middle Osagean anchoralis-latus conodont zone. Precise dating and paleobathymetric interpretations are based on the biostratigraphy and paleoecology of conodonts, and also of corals, calcareous and agglutinate foraminifera, and radiolarians. At this time, a shallow tropical sea covered most of the southern North Americ n craton and was the site for sedimentation of a broad carbonate platform. Surrounding this carbonate platform was a starved trough comprising several bathymetrically distinct starved basins. These starved basins lay on the inner (continentward) sides of foreland basins that were bordered on their outer sectors by orogenic highlands. The highlands formed in response to convergences or collisions with the North American continent by an oceanic plate to the west, by South America to the south, and by Africa and Europe to the east. During a eustatic rise of sea level that accompanied the orogenies and reached its maximum during the anchoralis-latus zone, the carbonate platform prograded seaward and carbonate sediments cascaded over the passive shelf margins to intertongue with thin carbonat slope deposits and very thin (~ 10 m) phosphatic basinal sediments. Simultaneously, thick (~ 500 m) flysch and deltaic terrigenous sediments, such as the Antler flysch on the west and the Borden and Pocono deltaic deposits on the east, were shed into the outer parts of the foreland basins from active margins along the orogenic highlands. This Mississippian reconstruction provides a unique opportunity for comparing and contrasting shelf-slope boundaries in parts of contemporaneous passive and active margins on three sides of Paleozoic continent.

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