Does magmatism influence low-angle normal faulting?

Geology
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Abstract

Synextensional magmatism has long been recognized as a ubiquitous characteristic of highly extended terranes in the western Cordillera of the United States. Intrusive magmatism can have severe effects on the local stress field of the rocks intruded. Because a lower angle fault undergoes increased normal stress from the weight of the upper plate, it becomes more difficult for such a fault to slide. However, if the principal stress orientations are rotated away from vertical and horizontal, then a low-angle fault plane becomes more favored. We suggest that igneous midcrustal inflation occurring at rates faster than regional extension causes increased horizontal stresses in the crust that alter and rotate the principal stresses. Isostatic forces and continued magmatism can work together to create the antiformal or domed detachment surface commonly observed in the metamorphic core complexes of the western Cordillera. Thermal softening caused by magmatism may allow a more mobile mid-crustal isostatic response to normal faulting.

Publication type Article
Publication Subtype Journal Article
Title Does magmatism influence low-angle normal faulting?
Series title Geology
DOI 10.1130/0091-7613(1993)021%3C0247:DMILAN%3E2.3.CO;2
Volume 21
Issue 3
Year Published 1993
Language English
Publisher Geological Society of America
Publisher location Boulder, CO
Description 4 p.
First page 247
Last page 250
Online Only (Y/N) N
Additional Online Files (Y/N) N
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