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

Nicolas Beaudoin (1) , Olivier Lacombe (2) , Nick M W Roberts (3) , Daniel Koehn (4)

1 LFCR - Laboratoire des Fluides Complexes et leurs Réservoirs
2 iSTeP - Institut des Sciences de la Terre de Paris
3 BGS - British Geological Survey
4 GeoZentrum Nordbayern

Thacker and Karlstrom (2019) commented on the paper of Beaudoin et al. (2018) by presenting a summary of the published data about exhumation of Laramide arches in Montana, northern Wyoming and western South Dakota. We thank the authors for this comment and wish to reply. Beaudoin et al. (2018) present U-Pb absolute ages of calcite cements that in-fill tectonic veins developed in the Bighorn basin during the Sevier and Laramide contractional events. At the scale of the basin, we report two trends: (1) an eastward, forelandward propagation of Sevier layer-parallel shortening vein development; and (2) a westward, hinterlandward propagation of Laramide layer-parallel shortening and folding-related vein development. We discuss the consistency between the latter Laramide sequence, valid in the sedimentary cover at the scale of the Bighorn basin, and the published exhumation sequence of the basement arches bounding the basin, i.e. Beartooth arch (West), Wind River range (South) and Bighorn arch (East) (Peyton et al., 2012, Crowley et al., 2002, Fan and Carrapa, 2014, Stevens et al., 2016).

Domaines: Tectonique

Nicolas Beaudoin, Olivier Lacombe, Nick M W Roberts, Daniel Koehn. U-Pb dating of calcite veins reveals complex stress evolution and thrust sequence in the Bighorn Basin, Wyoming, USA: REPLY. Geology, 2019, 47 (9), pp.e481. ⟨10.1130/G46606Y.1⟩. ⟨hal-02374281⟩