Early Cambrian alkaline volcanism on the southern margin of Laurentia: evidence in the volcaniclastic units from the Puerto Blanco Formation in the Caborca block, NW Mexico
Por:
Joaquin Barron-Diaz, Arturo, Abraham Paz-Moreno, Francisco, Lozano-Santa Cruz, Rufino, Herrera-Urbina, Saul, Centeno-Garcia, Elena, Lopez-Martinez, Margarita
Publicada:
3 jul 2019
Categoría:
Geology
Resumen:
Volcaniclastic units are exposed at the base of the Puerto Blanco
Formation in the Caborca region, northwestern Mexico. The lower unit
reveals the presence of Early Cambrian mafic volcanism in this region.
It consists of a volcano-sedimentary sequence represented by tuffaceous
conglomerates, agglomerates, lapillistones, tuffs, and altered mafic
volcanic flows. Petrographic analysis classified the volcanic clasts as
albite-sphene-calcite-actinolite granofels, with a moderate to intense
hydrothermal alteration, precisely characterized by EPMA analysis.
Albite-actinolite geothermometry indicates temperatures from 400 to 500
degrees C, suggesting metamorphic conditions in the upper temperature
greenschist facies. Geochemistry analysis shows a high TiO2
basic-ultrabasic volcanism that originated the volcanic clasts. Rock
protoliths were studied using immobile trace elements, which classified
them as OIB-type alkaline basalts with the characteristic spider
hump-shaped pattern, situated in an anorogenic intracontinental tectonic
setting with enriched mantle signatures. Ar-40/Ar-39 geochronology shows
metamorphic ages of 52.58 +/- 2.0 and 91.67 +/- 0.55 Ma, consistent with
the emplacement of Laramidic granitoids identified in the region.
Possible correlations of this alkaline volcanism include the Southern
Oklahoma Aulacogen and the late stages of the rifting of north western
Laurentia represented in western United States.
Filiaciones:
Joaquin Barron-Diaz, Arturo:
Univ Nacl Autonoma Mexico, Inst Geol, Hermosillo, Sonora, Mexico
Abraham Paz-Moreno, Francisco:
Univ Sonora, Dept Geol, Hermosillo, Sonora, Mexico
Lozano-Santa Cruz, Rufino:
Univ Nacl Autonoma Mexico, Inst Geol, Lab Nacl Geoquim & Mineral, Mexico City, DF, Mexico
Laboratorio Nacional de Geoquímica y Mineralogía, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
Herrera-Urbina, Saul:
Univ Sonora, Dept Geol, Hermosillo, Sonora, Mexico
Departamento de Geología, Universidad de Sonora, Hermosillo, Mexico
Centeno-Garcia, Elena:
Univ Nacl Autonoma Mexico, Inst Geol, Lab Nacl Geoquim & Mineral, Mexico City, DF, Mexico
Laboratorio Nacional de Geoquímica y Mineralogía, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
Lopez-Martinez, Margarita:
Ctr Invest Cient & Educ Super Ensenada, Ensenada, Baja California, Mexico
Centro de Investigación Científica y Educación Superior de Ensenada, Ensenada, Mexico
Instituto d e Geología, Universidad Nacional Autónoma de México, Hermosillo, Mexico
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