Late Cretaceous to early Paleogene syntectonic deposition of the Show Goat formation in the northern Chiricahua Mountains, southeast Arizona

Abstract We investigated the Wood Mountain fault and the Show Goat formation in the northern Chiricahua Mountains in southeast Arizona, USA, to resolve the timing, style, and distribution of Late Cretaceous to Paleogene contractional deformation in the southern U.S. portion of the North American Cordillera. The Wood Mountain fault is a thin-skinned, low-angle to subhorizontal thrust fault that places Upper Paleozoic carbonate rocks structurally over the Upper Cretaceous to Paleocene Show Goat formation. The Show Goat formation is an ~420-m-thick succession of syntectonic clastic and volcanic strata that overlie a prominent angular unconformity above steeply dipping mid-Cretaceous–age rocks of the Bisbee Group. The angular unconformity records initial uplift and erosion related to the onset of regional contractional deformation. New zircon U-Pb data indicate deformation started at ca. 90–73 Ma. The lower Show Goat formation consists of alluvial-fan deposits that formed adjacent to uplifted fault blocks. The upper Show Goat formation records the development of a local volcanic center and primarily consists of lithic tuffs, ash-rich mudstones interpreted as volcanic mudflows, and andesitic lava flows and ash-flow tuffs. New detrital and igneous zircon U-Pb geochronology data constrain deposition of the Show Goat formation between 73 Ma and 63 Ma. New zircon U-Pb data from volcaniclastic deposits of the Bobcat Hill Formation in the Peloncillo Mountains, New Mexico, USA, located ~30 km east of the Chiricahua Mountains, indicate regional volcanism and syntectonic sedimentation started ca. 80 Ma. A compilation of regional syntectonic deposits suggests that Late Cretaceous to Paleogene contractional deformation cannot be characterized by a single deformation front propagating toward the foreland. Locally, deformation may have been out-of-sequence or episodic. Syntectonic basins in southeast Arizona and southwest New Mexico were relatively small and localized, formed within an actively deforming orogenic wedge, and were not part of a spatially continuous basin or depocenter.