Yeso Formation

Yeso Formation
Name	Yeso Formation
Type	Geological formation
Period	Cisuralian to Guadalupian (Permian)
Primary lithology	Sandstone, siltstone, shale
Other lithology	Limestone, gypsum, evaporites
Namedfor	Yeso Creek
Region	New Mexico, Texas, Colorado
Country	United States

Yeso Formation The Yeso Formation is a Permian stratigraphic unit exposed across central and northern New Mexico, western Texas, and southeastern Colorado. It forms part of a sedimentary succession that includes the San Andres Formation, the Abo Formation, and the overlying Glorieta Sandstone, and records changing depositional regimes on the southwestern margin of the Pangea supercontinent. The unit is important for regional correlations, paleoclimatic reconstructions, and economic resources such as groundwater and evaporite minerals.

Introduction

The Yeso Formation crops out in the Sangre de Cristo Mountains, the Manzano Mountains, the Jemez Mountains, the Capitan Reef, and along the Rio Grande corridor, and is mapped in basin settings like the Raton Basin and the San Juan Basin. It bridges lithostratigraphic frameworks developed by the United States Geological Survey and state geological surveys including the New Mexico Bureau of Geology and Mineral Resources and the Texas Bureau of Economic Geology. Regional mapping ties the unit to Permian sequences studied in the Basin and Range Province and the Ancestral Rocky Mountains foreland.

Stratigraphy and Lithology

The Yeso Formation is typically subdivided into members and tongues characterized by alternations of fine- to medium-grained Sandstones, siltstones, shales, thin Limestone beds, and locally thick beds of gypsum and other evaporites. In some exposures it is conformably underlain by the red beds of the Abo Formation and overlain by the marine carbonates of the San Andres Formation or by the fluvial Glorieta Sandstone depending on structural position. Sedimentary structures such as cross‑bedding, ripple marks, mudcracks, and planar lamination indicate a mix of coastal sabkha, tidal flat, deltaic, and shallow marine settings recognized in studies by researchers affiliated with University of New Mexico, New Mexico Institute of Mining and Technology, and the Smithsonian Institution. Lateral facies changes link the Yeso to contemporaneous units across the Permian Basin and to sequences described in the Guadalupian stratigraphy of West Texas.

Age and Depositional Environment

Biostratigraphic and radiometric constraints place the Yeso Formation in the early to middle Permian (Cisuralian to Guadalupian). Correlations use fusulinid faunas, conodont assemblages, and detrital zircon provenance studies performed in collaboration with institutions such as Purdue University and Stanford University. The depositional environment reflects a transgressive–regressive cycle along the western shelf of Pangea with intervals of arid coastal sabkha and evaporitic concentration interrupted by storm-influenced shallow marine incursions. Paleogeographic reconstructions by researchers at the American Association of Petroleum Geologists link the Yeso to broader Permian eustatic changes observed in the Midcontinent Rift and the Ancestral Rocky Mountains hinterland.

Paleontology

Although not as fossiliferous as coeval marine carbonates, the Yeso yields important paleontological records including trackways attributed to early Permian tetrapods and reptiliomorphs, plant fragments including pteridosperm and cordaitalean remains, and invertebrate assemblages such as bivalves and gastropods in marine interbeds. Ichnological studies involving trace fossils have been published by collaborators at the Smithsonian Institution, University of California, Berkeley, and Harvard University and provide evidence for terrestrial–marine interaction zones similar to those documented in the Cisuralian deposits of European Russia and China. Palynological work conducted with teams from University of Kansas and Ohio State University has aided paleoenvironmental interpretations and age determinations.

Economic Resources and Use

The Yeso Formation hosts aquifers exploited for municipal and agricultural water supplies in parts of New Mexico and Texas, with hydrogeological assessments performed by the United States Geological Survey and state water agencies. Evaporite horizons supply gypsum and related industrial minerals mined historically by companies operating in the Permian Basin and documented by the Bureau of Land Management. Thin carbonate and sandstone reservoirs have been evaluated for petroleum potential by firms and consortia represented at meetings of the American Petroleum Institute and the Society of Petroleum Engineers, though major hydrocarbon production is more commonly associated with adjacent Permian units like the San Andres Formation and the Leonardian strata.

History of Investigation and Naming

The unit was named for exposures along Yeso Creek and was first described in early 20th‑century mapping by geologists affiliated with the United States Geological Survey and the New Mexico School of Mines. Subsequent revisions and member-level definitions have been advanced by researchers at the New Mexico Bureau of Mines and Mineral Resources and by academic investigators from University of Texas at Austin and Colorado School of Mines. Key twentieth-century contributions include regional stratigraphic syntheses and detailed sedimentological studies appearing in publications of the Geological Society of America and the Journal of Sedimentary Research, with ongoing work on sequence stratigraphy, isotope geochemistry, and basin modelling involving international collaborations with teams from University of Oxford and Uppsala University.

Category:Permian geology of New Mexico Category:Permian geology of Texas Category:Geologic formations of the United States