Detrital chromian spinels from Upper Ordovician deposits in the Precordillera terrane, Argentina: a mafic crust input.

P. ABRE, C.CINGOLANI, U. ZIMMERMANN & B. CAIRNCROSS

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

Elsevier

Lugar: London; Año: 2008 vol. XX p. 1 - 20

0895-9811

The study of heavy minerals from the Caradocian Pavón Formation (central Argentina) suggests that MORB and continental intraplate flood basalts were among the source rocks for the detrital record. The Pavón Formation was deposited on the disputed exotic Precordillera terrane. Provenance studies on this formation revealed sedimentary rocks characterized by an upper continental crustal component mixed with a mafic source, where the latter could not be described. The detrital chromian spinels provide more information about this component.             The detrital spinels were chemically separated into two groups. Group 1 shows characteristics typical for host rocks related to MORB (Cr# values are between 0.4 and 0.6, Fe2+# range from 0.2 to 0.4, and they have low TiO2 and low Fe3+# contents). Conversely, Group 2 has Cr# of 0.7, Fe2+# ranging from 0.5 to 0.8, higher Fe3+# and TiO2 contents up to 4.7% and they are related to continental flood basalts. Journal of South American Earth Sciences                                                   James N. Kellogg, Editor-In-Chief                                                             November 22, 2008 SA-609 “Detrital chromian spinels from Upper Ordovician deposits in the Precordillera terrane, Argentina: a mafic crust input” by P. Abre, C. Cingolani, U. Zimmermann, B. Cairncross Dear Dr. Cingolani, I am pleased to inform you that your revised paper “Detrital chromian spinels from Upper Ordovician deposits in the Precordillera terrane, Argentina: a mafic crust input” is accepted for publication in the Journal of South American Earth Sciences, Special Issue Mafic and Ultramafic Complexes of South America and the Caribbean, edited by M.P. Escayola and J.A. Proenza. This is an interesting well-written paper regarding the potential use of detrital spinels to define the provenance of a sequence of Ordovician sedimentary rocks on Precordillera basement, offering insight into the debate regarding the docking of this terrane with the proto-Andean margin of Gondwana. Sincerely,                                           James Kellogg, Editor-in-Chief Journal of South American Earth Sciences                                    James N. Kellogg, Editor-In-Chief                                                             November 22, 2008 SA-609 “Detrital chromian spinels from Upper Ordovician deposits in the Precordillera terrane, Argentina: a mafic crust input” by P. Abre, C. Cingolani, U. Zimmermann, B. Cairncross Dear Dr. Cingolani, I am pleased to inform you that your revised paper “Detrital chromian spinels from Upper Ordovician deposits in the Precordillera terrane, Argentina: a mafic crust input” is accepted for publication in the Journal of South American Earth Sciences, Special Issue Mafic and Ultramafic Complexes of South America and the Caribbean, edited by M.P. Escayola and J.A. Proenza. This is an interesting well-written paper regarding the potential use of detrital spinels to define the provenance of a sequence of Ordovician sedimentary rocks on Precordillera basement, offering insight into the debate regarding the docking of this terrane with the proto-Andean margin of Gondwana. Sincerely,                                           James Kellogg, Editor-in-Chief Journal of South American Earth Sciences                                    James N. Kellogg, Editor-In-Chief