Lower Wolfcampian conglomerate in the southern Caballo Mountains, Sierra County, New Mexico: stratigraphy, correlation, and implications for late Pennsylvanian-early Permian tectonics
Timothy F. Lawton, Katherine A. Giles, Greg H. Mack, David S. Singleton, and Alan D. Thompson
The upper part of the Bar B Formation in the Caballo Mountains, informally termed here the upper conglomeratic member of the Bar B Fon-nation, consists of pebble-, cobble-, and local boulder conglomerate interbedded with shale and limestone. The upper conglomeratic member thickens eastward across the southern Caballo Mountains from 7 to 107 m and unconformably overlies truncated Pennsylvanian sections at all studied localities. It is early Wolfcampian in age and equivalent to the type Bursum Formation of Socorro County. Detritus of the upper conglomeratic member was eroded from uplifted Pennsylvanian strata lying in and west of the Caballo Mountains and deposited in fandelta, shallow-marine, and subordinate fluvial settings on the western flank of the Orogrande basin. The upper conglomeratic member is part of a record of alternating uplift and subsidence of that basin margin from the early Pennsylvanian through the Early Permian. This polycyclic subsidence history and the geometry of the Orogrande basin are consistent with basin origin by strike-slip deformation of the craton, probably in response to progressive suturing of Gondwana and Laurentia.
- Lawton, Timothy F.; Giles, Katherine A.; Mack, Greg H.; Singleton, David S.; Thompson, Alan D., 2002, Lower Wolfcampian conglomerate in the southern Caballo Mountains, Sierra County, New Mexico: stratigraphy, correlation, and implications for late Pennsylvanian-early Permian tectonics, in: Geology of White Sands, Lueth, Virgil W.; Giles, Katherine A.; Lucas, Spencer G.; Kues, Barry S.; Myers, Robert; Ulmer, Scholle, Dana S., New Mexico Geological Society, Guidebook, 53rd Field Conference, pp. 257-265.