Coronado Volcanic Field

Coronado Volcanic Field
Name	Coronado Volcanic Field
Location	Arizona, Sonora, Mexico
Range	Basin and Range Province
Type	volcanic field
Last eruption	Pleistocene–Holocene (disputed)

Coronado Volcanic Field The Coronado Volcanic Field is a dispersed assemblage of basaltic to andesitic vents, cinder cones, lava flows and volcanic necks located along the borderlands of Arizona, Sonora and the Mexican Plateau. The field lies within the broader physiographic context of the Basin and Range Province, intersecting structural domains influenced by the Rio Grande Rift, the Gulf of California, and the Colorado Plateau margins. Its vents and deposits are studied in relation to regional volcanism that includes the San Francisco Volcanic Field, the El Pinacate volcanic field, and the Chihuahuan Desert volcanic occurrences.

Geology and Volcanic Features

The volcanic field comprises monogenetic cones, shield-like edifices, lava tubes, spatter ramparts and maar deposits mapped across exposures near Cochise County, Arizona, Pima County, Arizona, Sonoyta, and the Sierra de Sonora. Field mapping integrates stratigraphic correlations with work by institutions such as the United States Geological Survey, the Geological Society of America, and the Instituto Nacional de Estadística y Geografía to document vent alignments, scoria deposits, and pahoehoe to aa lava morphologies. Structural controls include lineaments coincident with the San Andreas Fault system extensions and the Whipple Mountains–Gila River corridor; eruptive products commonly overlie sedimentary sequences of the Basin and Range Province and the Mesa del Norte.

Age and Eruption History

Radiometric ages from potassium–argon and argon–argon determinations published by teams from Arizona State University, University of Arizona, and the Smithsonian Institution place most activity in the late Pliocene to Pleistocene, with a subset of ages interpreted as late Pleistocene to possible Holocene. Paleomagnetic studies cross-referenced with the global geomagnetic polarity timescale and correlated with archives from the Las Cienegas National Conservation Area and the Sonoran Desert indicate episodic eruptions over hundreds of thousands of years. Tephrochronology links distal ash layers to regional marker beds used by researchers at the National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography for basin-wide stratigraphy.

Petrology and Geochemistry

Lavas range from olivine basalt through basaltic andesite to hornblende-bearing andesite; xenolith suites include mantle-derived peridotite and crustal fragments similar to those reported from the Mogollon-Datil volcanic field and the Trans-Mexican Volcanic Belt. Major- and trace-element analyses by laboratories at the University of New Mexico and the Centro de Investigación Científica y de Educación Superior de Ensenada reveal enrichment in incompatible elements and variable isotopic signatures (Sr–Nd–Pb) that tie magmas to metasomatized subcontinental lithospheric mantle and to small contributions from crustal assimilation observed in studies of the Sierra Madre Occidental. Geochemical trends correlate with regional tectonic processes described in publications of the American Geophysical Union.

Structural Setting and Tectonics

The field occupies a complex intersection of extensional and transtensional regimes related to the opening of the Gulf of California and the southward propagation of the Basin and Range extension. Fault systems, including splays linking to the San Andreas Fault–Gulf of California transform network and northwest-oriented faults analogous to those in the Basin and Range Province, focus magma ascent and control vent distribution. Regional stress models developed by researchers at the Seismological Society of America and the Palo Alto Research Center demonstrate how lithospheric thinning, mantle flow beneath the Mojave Desert–Sonoran Desert transition, and slab edge processes influence alkalic basaltic magmatism.

Paleoclimate and Environmental Impact

Volcanic units preserve paleosols, charcoal horizons and lacustrine interbeds that have been used by paleoenvironmental studies from the University of California, Berkeley, the University of Arizona, and the Instituto Nacional de Antropología e Historia to reconstruct Pleistocene pluvial phases and Holocene aridity. Ash and tephra layers correlate with climatic oscillations recorded in the Beringia and Great Basin archives, offering regional markers for the Last Glacial Maximum and Younger Dryas intervals. Volcanic topography influenced paleodrainage patterns of the Gila River and habitat distribution for megafauna studied by paleontologists at the Smithsonian Institution and the American Association of Physical Anthropologists.

Human History and Cultural Significance

Archaeological surveys by teams from the Arizona State Museum, the University of Arizona, and the Instituto Nacional de Antropología e Historia document indigenous use of volcanic glass and obsidian procurement networks linking to Hohokam and Tohono O'odham territories; obsidian sourcing ties to geochemical fingerprints used by the Peabody Museum of Archaeology and Ethnology. Historic-era ranching, mining claims recorded in Bureau of Land Management archives, and exploratory reports by 19th-century figures such as John C. Frémont and Edward Fitzgerald Beale intersect with Spanish colonial routes documented by the Archivo General de la Nación (Mexico). The field has cultural resonance in Native American oral histories preserved by the Tohono Oʼodham Nation and the Yaqui.

Conservation and Research Activities

Portions of the volcanic field fall within conservation units like the Coronado National Forest, the Cabeza Prieta National Wildlife Refuge, and Mexican protected areas administered by the Comisión Nacional de Áreas Naturales Protegidas. Ongoing research programs involve collaborations among the United States Geological Survey, CONACYT-affiliated centers, and universities such as University of California, Santa Cruz and New Mexico Institute of Mining and Technology focusing on hazard assessment, geochronology, and geophysical imaging. Citizen science, outreach by the National Park Service, and cross-border initiatives with the Consejo Nacional de Ciencia y Tecnología promote monitoring, preservation of archaeological sites, and educational opportunities.

Category:Volcanic fields Category:Geology of Arizona Category:Geology of Sonora