Potrillo volcanic field

Potrillo volcanic field
Name	Potrillo volcanic field
Location	Doña Ana County, New Mexico; near El Paso, Texas
Type	Volcanic field
Last eruption	Holocene

Potrillo volcanic field is a volcanic field in southern New Mexico and near El Paso, Texas characterized by basaltic volcanism, shield volcanoes, cinder cones, and extensive lava flows. It lies within the broader Basin and Range Province and is part of a chain of Quaternary volcanic centers influenced by extensional tectonics and mantle upwelling. The field has been studied for its implications for Rio Grande Rift development, regional geothermal potential, and Holocene human-environment interactions.

Geography and setting

The volcanic field occupies a portion of Doña Ana County, New Mexico and abuts the urban area of El Paso, Texas, situated on the Tularosa Basin margin and adjacent to Organ Mountains and the San Andres Mountains. Topography includes broad basaltic plateaus, lava-filled basins, and isolated volcanic constructs that influence drainage into the Rio Grande and local playa systems such as the Salt Flats near White Sands National Park. Climate is arid to semi-arid, influenced by the North American Monsoon and proximity to the Chihuahuan Desert, with land use including grazing, military ranges such as Fort Bliss, and protected areas.

Geology and volcanology

Geologically the field is situated within the southern segment of the Rio Grande rift and overlies Precambrian basement and Paleozoic strata of the Permian Basin margin. Basalts are predominantly alkaline to tholeiitic and are interpreted as products of partial melting related to lithospheric extension similar to volcanic suites in the Jemez Mountains and Zuni-Bandera Volcanic Field. Geochemical studies correlate erupted magmas with mantle sources akin to those beneath the Basin and Range Province and the Trans-Pecos volcanic field, showing trace-element signatures diagnostic of small-degree melting and variable crustal contamination. Structural controls include fault sets linked to the Organ-Caldera (hypothetical) area and the Robledo Mountains faulting regime.

Volcanic features and landforms

The field hosts a diversity of volcanic landforms: low shields comparable to Kilbourne Hole maar-associated centers, polygenetic cinder cones, ʻaʻā and pāhoehoe lava flows, and collapse structures. Notable features include long pāhoehoe lobes, extensive ʻaʻā fields that abut alluvial fans, and maar craters that record phreatomagmatic interaction with groundwater similar to features in the Jornada del Muerto region. Lava tube remnants, spatter ramparts, and scoria deposits showcase eruptive variability akin to those documented at Capulin Volcano and Cerro Prieto (Mexico).

Eruption history and chronology

Eruptive activity spans Pliocene to Holocene, with radiometric ages and paleomagnetic data constraining many flows to Pleistocene and some vents to the Holocene epoch. Geochronology using K–Ar and Ar–Ar methods links late Quaternary eruptions with regional climatic shifts and rift-related faulting episodes similar in timing to basaltic events in the Taos Plateau volcanic field. Tephrochronology and stratigraphic correlations connect younger flows to archaeological horizons and geomorphic surfaces used in regional correlation.

Paleoclimate, ecology, and soils

Lava flows, tephra, and volcanic soils have influenced hydrology, vegetation, and pedogenesis across an ecotone between the Chihuahuan Desert and montane scrub. Volcanic substrates produce thin, stony soils that support creosote bush, mesquite, and grasses characteristic of desert grassland communities analogous to those in the Hueco Mountains and Sacramento Mountains foothills. Paleoclimatic reconstructions using lake-level evidence from nearby playas and packrat midden records indicate fluctuations in Holocene precipitation tied to shifts in the North American Monsoon and teleconnections with the El Niño–Southern Oscillation.

Human history and archaeology

Indigenous occupation around volcanic landforms is documented through lithic scatters, hearths, and aggraded soils, with evidence for prehistoric tool-making using vesicular basalt similar to artifacts from Chaco Canyon trade networks and regional Paleoindian sites. Historic era interactions include Spanish colonial expeditions along the El Camino Real de Tierra Adentro route, nineteenth-century Anglo-American settlement, and 20th-century military and mining land uses that intersect with archaeological sites administered by Bureau of Land Management and state agencies. Rock art panels and campsite locations near volcanic features provide insight into resource use and landscape perception among Puebloan and Apachean groups.

Conservation, hazards, and land use

Conservation efforts address habitat protection, cultural resource stewardship, and conflicts with livestock grazing, military training at Fort Bliss, and mineral exploration. Hazards include low-probability basaltic eruptions, lava flow inundation, and localized seismicity associated with rift faulting comparable to risks assessed for the Valles Caldera and Mount Taylor regions. Land-use planning integrates paleovolcanic mapping, geothermal assessment, and monitoring frameworks used by agencies such as the United States Geological Survey and state geological surveys to manage volcanic risk, water resources, and recreational access.

Category:Volcanic fields of New Mexico Category:Landforms of Doña Ana County, New Mexico