Genetic implications of new Sr and Nd isotopic data of the intrusive rocks from the Laramide Arc in Northern Sonora, Mexico.

  • E. Pérez-Segura Department of Geology, University of Sonora, Rosales y Bd. Luis Encinas, 83000, Hermosillo, Sonora, Mexico
  • E. González-Partida Center of Geociences, National University of Mexico, Campus Juriquilla, 76, 230, Querétaro, Qro., Mexico.
  • J. Roldán-Quintana Regional Northwest Station (ERNO), Institute of Geology, National University of Mexico, Bd. Luis Donaldo Colosio y Madrid, Hermosillo, Sonora, Mexico.
Keywords: Sonora, Mexico, Laramide intrusive arc, Sr-Nd isotopes, geochronology.

Abstract

The Laramide Intrusive Arc constitutes a wide intrusive belt broadly parallel to the actual Sonora coastline. It was formed by the subduction of the Farallon Plate beneath the North-American Plate during the Late Cretaceous-Early Tertiary period. New isotopic data on rocks of this arc show initial 87Sr/86Sr and eNd isotopic values of 0.7066 to 0.7070 and -5 to -6, respectively, for two samples from Bacanora area; as well as 0.7074 to 0.7081 and -3 to -5.5 respectively, for five samples from Cananea, Mariquita and La Caridad areas. Isotopic ages were determined by U/Pb in zircons (95 Ma) and Ar/Ar in potassic feldspar (56 to 71 Ma) from a quartz monzonite porphyry, and by Ar/Ar in potassic feldspar (56 Ma) from another plutonic granodiorite, both from Bacanora. Initial 87Sr/86Sr and eNd values for samples reported in this study suggest that the Laramidic magmas had a large influence from the Proterozoic basement in northeastern Sonora. Four different isotopic zones are proposed for Sonora, according with Sr-Nd data of laramidic rocks and the substratum intruded.

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Published
2013-04-15
How to Cite
Pérez-Segura E., González-Partida E. y Roldán-Quintana J. (2013). Genetic implications of new Sr and Nd isotopic data of the intrusive rocks from the Laramide Arc in Northern Sonora, Mexico. Journal of Iberian Geology, 39(1), 131-146. https://doi.org/10.5209/rev_JIGE.2013.v39.n1.41755