Whale Basin, Offshore Newfoundland: Extension and Salt Diapirism
Published:January 01, 1989
H. R. Balkwill, F. D. Legall, 1989. "Whale Basin, Offshore Newfoundland: Extension and Salt Diapirism", Extensional Tectonics and Stratigraphy of the North Atlantic Margins, A. J. Tankard, H. R. Balkwill
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Whale basin is part of the southern Grand Banks Mesozoic extensional mosaic. Basins in this domain were generated by cratonic extension before and during opening of the western Atlantic Ocean.
Long, relatively straight basement extension faults form the boundaries of Whale basin and are also important intrabasin elements. Some of these large faults are parallel to the trend of Paleozoic Appalachian tectonic elements, upon which the Mesozoic structures are superposed. The Mesozoic faults cut thick successions of Triassic and Jurassic terrigenous clastic strata and carbonates deposited during phases ofcrustal extension. A regional, planar unconformity separates those beds from drift-phase Aptian and younger rocks composing a seaward-thickening continental terrace wedge.
Immense, systematically aligned evaporite dia-pirs have intruded the synextensional rocks along basin-bounding faults and above clusters of sub-evaporite basement faults. A few small diapirs have risen from intrusive walls and penetrated terrace-wedge cover rocks.
Seismic evidence from Whale basin and other Grand Banks basins indicates that the geometries and motions of basement extensional faults can impose significant influences on the patterns, amounts, and times of salt intrusion. The diapiric patterns developed during rifting can be maintained by intraplate extension during postrift, passive-margin evolution.
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Extensional Tectonics and Stratigraphy of the North Atlantic Margins
Stimulated by the wealth of frontier exploration data and deep seismic surveys about the North Atlantic margins, this publication was crafted to provide a comprehensive analysis of North Atlantic extension. The 40 papers in this volume are divided into 6 sections: concepts, North Atlantic perspectives, North American margins, European-African margins, North Sea and Barents Shelf, and analogs. This book is concerned primarily with the circum-North Atlantic data base. It is largely biased toward presentation and interpretation of data rather than being model driven. The book includes comparative stratigraphic columns for basins of the North Atlantic margins.