Tectonic evolution of a Laramide transverse structural zone: Sweetwater Arch, south central Wyoming

摘要: Structural, anisotropy of magnetic susceptibility (AMS), and paleomagnetic data record patterns layer-parallel shortening (LPS), vertical-axis rotation, regional fault-fold evolution across the Sweetwater Arch, a major west to WNW trending, basement-cored Laramide uplift in Wyoming. The southern arch flank is bounded by striking reverse fault zone that imbricated basement cover rocks, northern with component strike-slip NW trending en echelon folds, eastern plunge transitions into an area multiple-trending faults folds. Synorogenic strata from Maastrichtian Early Eocene time, followed collapse. LPS, development systematic minor sets AMS lineations, preceded large-scale folding. LPS directions, estimated both data, were oriented WSW along flank, subparallel shortening, but refracted SSW plunge. Additional developed steep fold limbs during continued directions remaining becoming more variable where increasingly heterogeneous stress field as additional activated heterogeneities. Vertical-axis rotation was limited flanks, whereas underwent counterclockwise rotation. Deflections partly related heterogeneities, including weak supracrustal belts on strong granitic core, local reactivation Precambrian shear zones.