English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/205252
Share/Impact:
Statistics
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 | DATACITE
Exportar a otros formatos:

Title

Geochemistry of Eocene-Early Oligocene low-temperature crustal melts from Greater Himalayan Sequence (Nepal): a nanogranitoid perspective

AuthorsBartoli, Omar; Acosta-Vigil, Antonio ; Cesare, Bernardo; Remusat, L.; González-Cano, Adriana; Wälle, Markus; Tajčmanová, Lucie; Langone, Antonio
Issue Date3-Oct-2019
PublisherSpringer
CitationContributions to Mineralogy and Petrology 174: 82 (2019)
AbstractDespite melt inclusions in migmatites and granulites provide a wealth of information on crustal anatexis in different geological scenarios, a complete compositional study (including trace elements and HO) is yet to be made for the Himalayan rocks. In this contribution, we focus on nanogranitoids occurring in peritectic garnet of migmatites from Kali Gandaki valley in central Nepal (Greater Himalayan Sequence, GHS). The microstructural position of the nanogranitoids proves that these melts were produced at 650–720 °C and 1.0–1.1 GPa, during the Eohimalayan prograde metamorphism (41–36 Ma) associated with crustal thickening. Nanogranitoid compositions (mostly granodiorites, tonalities and trondhjemites) resemble those of experimental melts produced during HO-present melting of meta-sedimentary rocks. They have variable HO concentrations (6.5–14.4 wt%), which are similar to the expected minimum and maximum values for crustal melts produced at the inferred P–T conditions. These compositional signatures suggest that melt formation occurred in the proximity of the HO-saturated solidus, in a rock-buffered system. The low-to-very low contents of Zr (3–8 ppm), Th (0.1–1.2 ppm) and LREE (4–11 ppm) along with the weak-to-moderate positive Eu anomalies (Eu/Eu* = 1.2–3.3), the high B concentrations (200–3400 ppm) and the high U/Th ratio (up to 21) point to the lack of equilibration between melt and accessory minerals and are consistent with melting of plagioclase at low temperature. Kali Gandaki nanogranitoids record the beginning of melting in a HO-present system that, in other GHS localities, may have produced voluminous crustal melts. We demonstrate that compositional comparison with nanogranitoids may be useful to reconstruct the petrogenesis of Eohimalayan granitoids.
Publisher version (URL)http://dx.doi.org/10.1007/s00410-019-1622-2
URIhttp://hdl.handle.net/10261/205252
DOI10.1007/s00410-019-1622-2
Identifiersdoi: 10.1007/s00410-019-1622-2
issn: 1432-0967
Appears in Collections:(IACT) Artículos
Files in This Item:
File Description SizeFormat 
accesoRestringido.pdf15,38 kBAdobe PDFThumbnail
View/Open
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.