New Mexico Geological Society Annual Spring Meeting — Abstracts

Canoncito de la Uva, in central Socorro County on the edge of the Rio Grande rift, has Paleozoic rocks and later structural features. Pennsylvanian Burrego, Story, Del Cuerto, and Moya Formations represent marine deposition. Regression and influx of clastic sediments began with Permian Bursum deposition, and reached a climax as the fluviatile Abo Formation was deposited. Yeso sandstone, limestone and gypsum indicate a return of marine conditions.

The marine and nonmarine sediments are cut and folded by a suite of features suggestive of a wrench regime. North-northwest trending folds with eastward vergence, north-northwest striking high-angle reverse faults, and northeast striking apparently strike-slip faults indicate a transpressive regime of northnortheast, right-lateral displacement, with east-northeast directed compression. Other fold axes trend northeastward, and suggest a separate period of transpression with northeast displacement and southeast-directed compression. Thrust faults and overturned strata further north in the Los Pinos support transpressional hypotheses. Small northwest trending grabens and extension of the Abo Formation along northerly faults show transtension has also affected the area.

Absolute dating of these events in the Canoncito de la Uva area has not been possible, because Tertiary volcanics and sediments are not present in the area. Similaarity to Laramideage compression to the north and south suggest this deformation is also of Laramide age.