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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 57 (1973)

Issue: 5. (May)

First Page: 956

Last Page: 957

Title: Petroleum Exploration and New Basement Tectonics: ABSTRACT

Author(s): S. Parker Gay, Jr.

Article Type: Meeting abstract

Abstract:

Mounting evidence from important geologic studies of many types--surface geology, standard airphoto interpretation, space photography, gravity, magnetics, and side-looking radar imagery--demonstrates that the earth's Precambrian crust is profoundly and systematically fractured. These basement fractures fall into a few sets of parallel structures that have been reactivated by local and regional tectonism at various times subsequent to their formation. Thus, they control, to a very large degree, all geologic structures, particularly structures in the sedimentary blanket overlying Precambrian basement. An understanding of basement fracturing is thus of enormous importance in petroleum exploration and will become a major exploration technique in the coming years. Strain theor is relegated

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to a much lesser role than formerly, applying only to blocks of unfractured rock a few kilometers on a side, if such exist.

The studies to date indicate that the basement fracture sets formed in orthogonal, i.e., right angle, patterns; that the fractures of different sets trend through one another with little or no displacement, and hence resulted from vertical, rather than horizontal forces; and that they are very old. One key study of aeromagnetics on the Colorado Plateau indicates that the minimum age of the fracturing is 1.7 billion years. Several mechanisms for the formation of these sets have been proposed.

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Copyright 1997 American Association of Petroleum Geologists