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Title: Basement extension and salt mobility, southern Grand Banks, Newfoundland

Abstract

The Grand Banks, an especially wide cratonic segment of the North American Atlantic continental shelf, extended vigorously during Late Triassic-Aptian rift-phase episodes, accompanied by syntectonic basin filling and large-scale structural disruption. Thereafter, the rift-disrupted domain underwent drift-phase subsidence and was buried by a seaward-prograding continental terrace wedge, in which progressively feeble extension is evident. Rift-faulted cratonic basement is perceptible on industry-acquired reflection seismic profiles from the southern Grand Banks. The profiles also show that Carboniferous and Lower Jurassic salt were the main levels of supracrustal detachment during Jurassic and Early Cretaceous extension. Large salt-mobilized structures within the rift-phase succession include fault-zone sheaths, elongate pillows, aligned piercement spires, and immense walls. These elements parallel large extension faults in basement and, in many places, are superposed on the faults. In striking contrast, upper Aptian and younger drift-phase strata are regionally subhorizontal, and are broken to middle and late Tertiary stratigraphic levels by only a few small extension faults and aligned diapirs. The authors interpret the structural/stratigraphic relationships in the southern Grand Banks to indicate that episodic Mesozoic and Cenozoic basement extension was the principal dynamic agent in determining the timing of salt structures, their orientations, and styles of disruption on enclosing strata.more » This genetic association may be applicable to other parts of the Grand Banks tectonic province, and possibly to other extensional cratonic margin basins.« less

Authors:
;
Publication Date:
Research Org.:
Petro-Canada Resources, Calgary, Alberta
OSTI Identifier:
5353783
Report Number(s):
CONF-860624-
Journal ID: CODEN: AAPGB
Resource Type:
Conference
Journal Name:
Am. Assoc. Pet. Geol., Bull.; (United States)
Additional Journal Information:
Journal Volume: 70:5; Conference: American Association of Petroleum Geologists annual meeting, Atlanta, GA, USA, 15 Jun 1986
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; NEWFOUNDLAND; SALT DEPOSITS; SEDIMENTARY BASINS; CONTINENTAL SHELF; CRETACEOUS PERIOD; TRIASSIC PERIOD; CANADA; CONTINENTAL MARGIN; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; ISLANDS; MESOZOIC ERA; NORTH AMERICA; 020200* - Petroleum- Reserves, Geology, & Exploration

Citation Formats

Balkwill, H R, and Legall, F. Basement extension and salt mobility, southern Grand Banks, Newfoundland. United States: N. p., 1986. Web.
Balkwill, H R, & Legall, F. Basement extension and salt mobility, southern Grand Banks, Newfoundland. United States.
Balkwill, H R, and Legall, F. 1986. "Basement extension and salt mobility, southern Grand Banks, Newfoundland". United States.
@article{osti_5353783,
title = {Basement extension and salt mobility, southern Grand Banks, Newfoundland},
author = {Balkwill, H R and Legall, F},
abstractNote = {The Grand Banks, an especially wide cratonic segment of the North American Atlantic continental shelf, extended vigorously during Late Triassic-Aptian rift-phase episodes, accompanied by syntectonic basin filling and large-scale structural disruption. Thereafter, the rift-disrupted domain underwent drift-phase subsidence and was buried by a seaward-prograding continental terrace wedge, in which progressively feeble extension is evident. Rift-faulted cratonic basement is perceptible on industry-acquired reflection seismic profiles from the southern Grand Banks. The profiles also show that Carboniferous and Lower Jurassic salt were the main levels of supracrustal detachment during Jurassic and Early Cretaceous extension. Large salt-mobilized structures within the rift-phase succession include fault-zone sheaths, elongate pillows, aligned piercement spires, and immense walls. These elements parallel large extension faults in basement and, in many places, are superposed on the faults. In striking contrast, upper Aptian and younger drift-phase strata are regionally subhorizontal, and are broken to middle and late Tertiary stratigraphic levels by only a few small extension faults and aligned diapirs. The authors interpret the structural/stratigraphic relationships in the southern Grand Banks to indicate that episodic Mesozoic and Cenozoic basement extension was the principal dynamic agent in determining the timing of salt structures, their orientations, and styles of disruption on enclosing strata. This genetic association may be applicable to other parts of the Grand Banks tectonic province, and possibly to other extensional cratonic margin basins.},
doi = {},
url = {https://www.osti.gov/biblio/5353783}, journal = {Am. Assoc. Pet. Geol., Bull.; (United States)},
number = ,
volume = 70:5,
place = {United States},
year = {Thu May 01 00:00:00 EDT 1986},
month = {Thu May 01 00:00:00 EDT 1986}
}

Conference:
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