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Titre du document / Document title

Compressional tectonic controls on Epicontinental black-shale deposition : Devonian-Mississippian examples from North America

Auteur(s) / Author(s)

ETTENSOHN F. R. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Geological Sciences, University of Kentucky, Lexington, KY 40506-0053, ETATS-UNIS

Résumé / Abstract

Epicontinental black-shale deposition spanned nearly one-quarter of North American parts of Laurussia during Late Devonian-Early Mississippian time. These shale deposits can be divided geographically into three, large-scale, basin complexes centered on foreland or peripheral basins that developed largely in response to deformational loading during three partially coeval compressional orogenies. The age and distribution of the shales support the strong influence of respective orogenies. The progressive westward spread of black-shale deposition in the Appalachian basin at this time, as well as migration of black-shale deposition into the sequentially yoked Michigan and Illinois basins, in part reflect flexural interactions and subsidence related to the Acadian orogeny. The southwestward extension of similar black-shale deposition beyond the Appalachian basin into Mississippi, Arkansas, Texas, Oklahoma, New Mexico, Arizona, Kansas, and westem Missouri reflects development of the Ouachita peripheral basin and the subsequent yoking of the Salina and Forest City basins during inception of Ouachita convergence in latest Devonian to Early Mississippian time. By Late Devonian time, moreover, the southward migration of the Antler orogeny onto U.S. parts of the Cordilleran margin similarly generated a subsiding foreland basin and ideal conditions for black-shale deposition in parts of that basin; almost simultaneously black-shale deposition spread eastward into the yoked Williston basin. Based on well known black-shale deposits from the eastern or Acadian basin complex, major epicontinental, black-shale deposits reflect two different tectonic and depositional settings. Black-shale deposition initiates proximally, soon after orogeny and deformational loading begin in rapidly subsiding parts of foreland basins where clastic influx is initially low and rapid subsidence generates early basin restriction. In the stratified water column that results, highly radioactive black shales rich in organic matter (>10 wt. %) and depleted in clastic components are deposited. Because they are deposited in deepening conditions, these shales are called transgressive black shales. In later stages of foreland-basin development, as clastic influx increases and subsidence moves broadly cratonward, the locus of black-shale deposition pushes into shallower, more distal parts of a growing epicontinental embayment developed behind rising tectonic highlands. Here, in the absence of widespread water-column anoxia, black-shale deposition is apparently favored by greatly enhanced organic productivity in nearly enclosed embayments that concentrate terrestrially derived nutrients and by sufficient sedimentation to protect sedimented organic matter at the sediment-water interface. These shales exhibit lesser radioactivities, lesser amounts of organic matter, and increased clastic content; locally they exhibit faunal and sedimentological evidence of shallower water and absence of anoxia. Stratigraphic evidence indicates that these black shales developed distally during later orogenic phases characterized by cratonward, clastic progradation; hence, they are called regressive black shales. Devonian-Mississippian black-shale deposition across much of Laurussia reflects a complex interplay of temporal, paleoclimatic, paleogeographic, eustatic, and biotic factors, any one of which may have mediated the influence of tectonism. Nonetheless, interpretations presented herein suggest that conditions conducive to black-shale deposition may be naturally inherent in the early development of foreland and peripheral basins and in the subsidence-related development of large, partially enclosed, epicontinental embayments behind rising tectonic highlands. In both situations, it is clear that compressive tectonic regimes contribute substantially to epicontinental, black-shale deposition through generation of suitable basin repositories and conditions that enhance organic productivity.

Source / Source

Shales and mudstones :   ( Volume I, Basin studies, sedimentology, and paleontology )
1998  , pp. 109-128[Note(s) : VI, 384 p., ] (3 p.) ISBN 3-510-65181-2 ; 3-510-65183-9 ;  Illustration : Illustration ;

Langue / Language

Anglais

Editeur / Publisher

E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, ALLEMAGNE  (1998) (Monographie)

Mots-clés anglais / English Keywords

United States

;

tectonic controls

;

Devonian

;

Mississippian

;

migration

;

foreland basins

;

subsidence

;

Acadian

;

orogeny

;

extension

;

black shale

;

compression tectonics

;

spatial distribution

;

paleogeography

;

North America

;

Paleozoic

;

Carboniferous

;

upper Paleozoic

;

Middle Cambrian

;

Cambrian

;

lower Paleozoic

;

clastic rocks

;

sedimentary rocks

;

Mots-clés français / French Keywords

Etats Unis

;

Contrôle tectonique

;

Dévonien

;

Mississippien

;

Migration

;

Bassin avant pays

;

Subsidence

;

Acadien

;

Orogenèse

;

Extension

;

Shale noir

;

Tectonique compression

;

Distribution spatiale

;

Paléogéographie

;

Amérique du Nord

;

Paléozoïque

;

Carbonifère

;

Paléozoïque sup

;

Cambrien moyen

;

Cambrien

;

Paléozoïque inf

;

Roche clastique

;

Roche sédimentaire

;

Mots-clés espagnols / Spanish Keywords

Estados Unidos

;

Control tectónico

;

Devónico

;

Mississippiense

;

Migración

;

Cuenca antepaís

;

Subsidencia

;

Orogénesis

;

Extensión

;

Distribución espacial

;

Paleogeografía

;

America del norte

;

Carbonífero

;

Cámbrico medio

;

Cámbrico

;

Roca clástica

;

Roca sedimentaria

;

Localisation / Location

INIST-CNRS, Cote INIST : L 26743, 35400008284326.0060

Nº notice refdoc (ud4) : 1809612



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