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Sr‐Nd isotope compositions of cenozoic granitoids along a traverse of the central Peruvian Andes
Author(s) -
Soler Pierre,
RotachToulhoat Nelly
Publication year - 1990
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350250317
Subject(s) - geology , magmatism , cenozoic , mantle (geology) , massif , crust , proterozoic , crustal recycling , geochemistry , tectonics , traverse , continental crust , paleontology , structural basin , geodesy
Sr‐Nd isotopic compositions of late Eocene to Pliocene intrusive rocks from a traverse (⋍11° lat. S) of the central Peruvian Andes are presented. The data set suggests that the calc‐alkaline magmatism is mainly the end‐product of the evolution at deep crustal levels of magmas derived from a slightly depleted, but not MORB‐type, subcontinental mantle, which have assimilated crustal material and have mixed with new batches of primary magma. Assimilation of crustal material increased eastwards and with time. The evolution of Sr‐Nd isotope compositions in time and space along the traverse reflect both the lateral heterogeneities in the subcontinental mantle, the lower crust composition, and the progressive tectonic thickening of the crust during the Cenozoic. No granulitic basement akin to the early Proterozoic south Peruvian Arequipa massif has participated in the genesis of the central Peruvian calc‐alkaline and alkaline magmas.