Sr-Nd isotope compositions of cenozoic granitoids along a traverse of the central Peruvian Andes
✍ Scribed by Pierre Soler; Nelly Rotach-Toulhoat
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 680 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0072-1050
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✦ Synopsis
Sr-Nd isotopic compositions of late Eocene to Pliocene intrusive rocks from a traverse (= 1 1 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 evoiution 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.