U-Pb dating of calcite veins reveals complex stress evolution and thrust sequence in the Bighorn Basin, Wyoming, USA

Beaudoin, N. , Lacombe, O., Roberts, N. M.W. and Koehn, D. (2018) U-Pb dating of calcite veins reveals complex stress evolution and thrust sequence in the Bighorn Basin, Wyoming, USA. Geology, 46(11), pp. 1015-1018. (doi:10.1130/G45379.1)

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We report U-Pb absolute ages of calcite cements from a diffuse vein network documented in the Bighorn Basin (Wyoming, USA), where distinct systematic vein sets developed at the front of the thin-skinned Sevier orogen, during Laramide layer-parallel shortening, and during thick-skinned Laramide thrusting and folding. The U-Pb age distribution illustrates: (1) an outward (eastward) transmission of Sevier orogenic stress (from 89.7 ± 2.9 Ma [2σ] in the west, and from 75.3 ± 2.8 Ma in the east); and (2) an inward (westward) development of Laramide-related fracturing and folding (72 ± 3.0 Ma and 45.4 ± 1.8 Ma, respectively, in the east; 60.5 ± 4.6 Ma and 27.9 ± 1.1 Ma, respectively, in the west), which is in accordance with the known sequence of exhumation of the major Laramide basement arches. Our results also show that the stress related to Laramide compression first overprinted the stress related to Sevier compression in the sedimentary cover around major basement uplifts. This study highlights the utility of U-Pb calcite geochronology as a powerful tool for constraining complex sequences of deformation in orogenic forelands.

Item Type:Articles
Additional Information:This work was funded by Sorbonne Université (Paris) through research agreement C14313 and the Natural Environment Research Council (UK) through NIGSFC grant IP-1494–1114.
Glasgow Author(s) Enlighten ID:Beaudoin, Dr Nicolas and Koehn, Dr Daniel
Authors: Beaudoin, N., Lacombe, O., Roberts, N. M.W., and Koehn, D.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Geology
Publisher:Geological Society of America
ISSN (Online):1943-2682
Published Online:08 October 2018
Copyright Holders:Copyright © 2018 Geological Society of America
First Published:First published in Geology 46(11): 1015-1018
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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