Re-Os and U-Pb geochronology of the El Arco porphyry copper deposit, Baja California Mexico: Implications for the Jurassic tectonic setting

V. A. Valencia, F. Barra, B. Weber, J. Ruiz, G. Gehrels, J. Chesley, M. Lopez-Martinez

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

New geochronologic data from the El Arco porphyry copper deposit, Baja California, Mexico, yield a Middle Jurassic crystallization U-Pb age of 164.7 ± 6.5 Ma for zircons from a granodiorite porphyry that hosts the Cu-Au-(Mo) mineralization, and four Re-Os molybdenite ages yield a weighted average age of 164.1 ± 0.4 Ma. These ages disagree with previous K-Ar age determinations that suggest a correlation of the intrusive rocks of El Arco-Calmalli area with the eastern Peninsular Ranges batholith of Cretaceous age. Instead, the volcanic-plutonic rocks of the El Arco-Calmalli area are more properly associated with the San Andres-Cedros volcanic-plutonic complex (∼166 Ma). El Arco-Calmalli block likely was part of the intraoceanic arc system described in the Vizcaino-Cedros region and accreted to the continent during the Cretaceous (98-110 Ma). The presence of a continental Jurassic magmatic arc in the mainland and the occurrence of El Arco-Calmalli (San Andres-Cedros) volcanic-plutonic complex indicate two Jurassic magmatic arcs at this latitude (continental and oceanic).

Original languageEnglish (US)
Pages (from-to)39-51
Number of pages13
JournalJournal of South American Earth Sciences
Volume22
Issue number1-2
DOIs
StatePublished - Nov 1 2006

Keywords

  • Baja California
  • El Arco
  • Jurassic magmatism
  • Porphyry copper deposits
  • Re-Os
  • U-Pb

ASJC Scopus subject areas

  • Geology
  • Earth-Surface Processes

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