INGEOSUR   20376
INSTITUTO GEOLOGICO DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Lithospheric Mantle Heterogeneities beneath Southern Patagonia.
Autor/es:
MUNDL, A.; NTAFLOS, TH.; BJERG, E. A.; ACKERMAN, L.; HAUZENBERGER, CH.
Revista:
Mineralogical Magazine
Editorial:
Ingenta Connect
Referencias:
Lugar: New York; Año: 2013 vol. 77 p. 1 - 2
Resumen:
Thirty samples from Pali Aike Volcanic Field (PAVF) and Tres Lagos in Southern Patagonia comprise Sp-lherzolites, Spharzburgites, Sp-Gt-lherzolites and Sp-Gt-harzburgites. According to Cpx REE and other trace element patterns, the samples can be divided in 3 Groups within Sp-peridotites and 3 within Sp-Gt-peridotites. Group I Sp-peridotites show a depletion in LREE reflecting different degrees of partial melting. Group II shows flat REE patterns from HREE to MREE with an enrichment in LREE indicating metasomatic overprint. Group III samples show an enrichment in MREE over LREE and HREE suggesting basaltic melt percolation. While Group I Sp-Gt-peridotites represents slightly depleted samples with typical REE patterns of Cpx in equilibrium with Gt, Group II Cpx REE patterns show LREE enrichments reflecting metasomatic event(s). The garnets in this group exhibit wide kelyphitic rims that have been formed according to the reaction of Gt+Ol to Sp+Cpx+Opx. Primary Sp inclusions in Gts of Group I and II indicate transitions from spinel to garnet stability field. Group III of Sp-Gt-peridotites is represented by highly depleted samples showing REE patterns otherwise typical for Cpx coexisting with Gt. However, an entire abscense of Gt suggests that all Gt has been consumed during partial melting event(s).