RT Journal Article
T1 Fast sediment underplating and essentially coeval juvenile magmatism in theOrdovician margin of Gondwana, Western Sierras Pampeanas, Argentina
A1 Casquet Martín, César
A1 Rapela, Carlos W.
A1 Pankhurst, R.J.
A1 Baldo, Edgardo G.
A1 Galindo Francisco, María Del Carmen
A1 Fanning, C.M.
A1 Dahlquist, Juan A.
AB Metasedimentary high-pressure upper amphibolite facies gneisses (1.2±0.1 GPa and 780±45 °C) at LasChacras, Sierra de Valle Fértil, are tectonically juxtaposed to thewesternmost parts (outboard) of the Famatinian(Early Ordovician) magmatic arc, which underwent syn-plutonic middle crust high-grade metamorphism atlower pressure. U–Pb SHRIMP zircon data suggest that the gneisses contain Famatinian igneous detritus, sothat their sedimentary protoliths were probably deposited in a forearc basin and then rapidly underthrust andaccreted to the lower crust of the arc, essentially coevallywith arc magmatismat 468±4 Ma. Chemically and isotopicallyjuvenile garnetiferous amphibolites within the gneisses are recognised as representing themost primitivemagmas so far observed in this belt, which has often been considered to be a continental arc derived fromisotopically mature sources. This is consistent with the idea that at least part of the dominant Famatinianmagmatism originated in depleted mantle but was heavily contaminated by crustal components.
PB Elsevier Science B. V., Amsterdam
SN 1342-937X
YR 2012
FD 2012
LK https://hdl.handle.net/20.500.14352/43853
UL https://hdl.handle.net/20.500.14352/43853
LA eng
DS Docta Complutense
RD 21 abr 2025