Abstract
Abstract: The Tseel terrane in the Gobi Desert of SW Mongolia consists of a composite crustal segment of imbricated sheets of high- and low-grade metamorphic rocks of predominantly middle Palaeozoic age. New sensitive high-resolution ion microprobe (SHRIMP) zircon ages of 396 ± 3 Ma (2σ) and 397 ± 3 Ma (2σ) for two calc-alkaline metarhyolite samples indicate arc volcanism during the early Devonian. An undeformed feldspar porphyry cross-cutting the early Devonian low-grade sequence yielded an emplacement age of 279 ± 2 Ma (2σ). Geochemical and Nd isotopic data for low-grade mafic metavolcanic rocks are consistent with melting of moderately depleted upper mantle sources in a transitional arc–back-arc setting. In addition, there are high- and low-grade felsic metaigneous rocks with subduction-related chemical signatures and heterogeneous Nd isotopic compositions indicating an origin from mixed sources, including juvenile and Precambrian crustal components. The field observations combined with the geochemical and isotopic data suggest that the Tseel terrane represents a segment of a mature Japan-type arc associated with a juvenile back-arc basin. Supplementary material: Latitudes and longitudes of sample localities, major- and trace-element abundances for rock samples, data for reference materials obtained by LA-ICP-MS and Sm–Nd isotopic data for rock samples are available at http://www.geolsoc.org.uk/SUP18338 .
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
