28 Geologic Mapping in the West (Posters)

This poster session highlights geologic mapping in the western Cordillera and Rocky Mountains. We encourage submissions that explore bedrock and surficial geology, geophysics, hydrology, hazards, and more. Both professional and student submissions are welcome.

Tuesday, 19 May 2026
8:00 AM - 5:30 PM
Alvarado D/E

Carbonates and Clastics Compiled in the land of Karsts: Geologic Map 82, the Carlsbad 30x60-Minute Quadrangle (1:100,000-scale), New Mexico and Texas

Paper number: 28-1
Program: Technical Sessions
Time: 8:15 AM – 8:15 AM

Authors

  • Jon Krupnick Presenting Author
    New Mexico Institute of Mining and Technology, Socorro, New Mexico
  • Tyler Askin
    New Mexico Institute of Mining and Technology, Socorro, New Mexico
  • Bruce Allen
    New Mexico Institute of Mining and Technology, Socorro, New Mexico
  • Michelle Gavel
    TerranearPMC LLC, Los Alamos, New Mexico
  • Victor Polyak
    University of New Mexico, Albuquerque, New Mexico

Abstract

This quadrangle hosts some of the most charismatic reef stratigraphy in the world as back-reef sediments of the Northwest Shelf grade into shelf-margin deposits of the Capitan Reef and drop-down slope into the Delaware Basin. Tectonic deformation of the Ancestral Rocky Mountain orogeny is visible in the subsurface as thrusting and growth strata in Paleozoic sedimentary units and as monoclinal folding at the surface in Permian strata. Limited faulting and folding are observed from the regional uplift that occurred during the Laramide orogeny. Extension from the Rio Grande Rift resulted in normal faulting and down dropping of the Brokeoff Mountains and exhumation and karst formation in the Guadalupe Mountains. A few outcrops of Cretaceous strata are found as karst collapse features. Pending detrital sanidine argon-argon geochronology ages hope to constrain the timing and provenance of these sediments’ original marine deposition. New argon-argon geochronology targeting the groundmass of a mafic-intermediate intrusive float provided a date of 28.167+/-0.29 Ma that varies from the existing date of 34.45+/-0.29 Ma on dike outcrops to the south. The late Cenozoic and Quaternary have a rich history of landscape change preserved in the ancestral Pecos River basin-fill sediments of the Gatuna Formation and recent alluvial and eolian deposits. New Uranium-Series dates of 328+/-21 ka (n=4) and 208+/-18 ka (n=4) provide minimum ages of petrocalcic soil development during the middle Pleistocene which help bracket the late stages of the Mescalero paleosol development preceding the entrenchment of the modern Pecos River.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410493

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