English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/126888
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:


Refertilization process in the Patagonian subcontinental lithospheric mantle of Estancia Sol de Mayo (Argentina)

AuthorsMelchiorre, Massimiliano; Coltorti, Massimo; Gregoire, M.; Benoit, M.
KeywordsMantle xenoliths
T–P–fO2 conditions
Issue Date2015
CitationTectonophysics 650: 124- 143 (2015)
Abstract© 2015 Elsevier B.V. Anhydrous mantle xenoliths equilibrated at 1003-1040°C from Estancia Sol de Mayo (ESM, Central Patagonia, Argentina) and entrained in post-plateau alkaline lavas belonging to Meseta Lago Buenos Aires have been investigated aiming at reconstructing the depletion and enrichment processes that affected this portion of the Patagonia lithospheric mantle. Xenoliths are characterized by a coarse-grained protogranular texture and are devoid of evident modal metasomatism. They show two texturally different clinopyroxenes: protogranular (cpx1) and texturally related to spinel (cpx2). Three different types of orthopyroxenes are also recognized: large protogranular crystals with exsolution lamellae (opx1); small clean and undeformed grains without exsolution lamellae (opx2) and small grains arranged in a vein (opx3). Major element composition of clinopyroxenes and orthopyroxenes highlights two different trends characterized by i) a high Al<inf>2</inf>O<inf>3</inf> content at almost constant mg# and ii) a slight increase in Al<inf>2</inf>O<inf>3</inf> content with decreasing mg#. Clinopyroxenes are enriched in LREE and are characterized by prominent to slightly negative Nb, Zr and Ti anomalies. No geochemical differences are observed between cpx1 and cpx2, while a discrimination can be observed between opx1 and opx2 (LREE-depleted; prominent to slightly negative Ti and Zr anomalies) and opx3 (prominent positive Zr anomaly). Partial melting modeling using both major and trace elements indicates a melting degree between ~5% and ~13% (up to ~23% according to major element modeling) for lherzolites and between ~20% and ~30% for harzburgites (down to ~5% according to trace element modeling). La/Yb and Al<inf>2</inf>O<inf>3</inf>, as well as Sr and Al<inf>2</inf>O<inf>3</inf> negative correlations in clinopyroxenes point to a refertilization event affecting this lithospheric mantle. The agent was most probably a transitional alkaline/subalkaline melt, as indicated by the presence of orthopyroxene in the vein and the similar geochemical features of ESM clinopyroxenes and those from Northern Patagonia pyroxenites which are derived from transitional alkaline/subalkaline lavas.
Publisher version (URL)http://dx.doi.org/10.1016/j.tecto.2015.02.015
Identifiersdoi: 10.1016/j.tecto.2015.02.015
issn: 0040-1951
Appears in Collections:(ICTJA) Artículos
Files in This Item:
File Description SizeFormat 
accesoRestringido.pdf15,38 kBAdobe PDFThumbnail
Show full item record
Review this work

Related articles:

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.