Deposition and emplacement of Permian reefs in Sierra Plomosa, Chihuahua, Mexico

Abstract

Permian reefs in Sierra Plomosa, Chihuahua are well exposed and contain shallow-water faunas similar to the better-studied rocks of the Permian Reef Complex in Texas and New Mexico. The reefs are dominantly mudstones with subordinate algal boundstones, packstones, and grainstones. Fusulinids indicate the reefs are Late Wolfcampian through at least Early Leonardian. The reefs are found in complicated juxtaposition to basinal clastic rocks of the Plomosas Formation. Thrusting is clearly responsible for the structural association in the Sierra Santo Domingo at the east end of the range. Sliding of reefal blocks into adjacent deep water may have occurred. Reefal olistoliths of shallow water origin are embedded in deep marine terrigenous clastics.