Evolution of the Lüliangshan garnet peridotites in the North Qaidam UHP belt, Northern Tibetan Plateau: Constraints from Re–Os isotopes

Os isotopic evidence for a carbonaceous chondritic mantle source for the Nagqu ophiolite from Tibet and its implications

“…Re-Os isotopes were obtained by isotope dilution techniques at the Guangzhou Institute of Geochemistry, CAS, where an increasing volume of Re-Os isotopic data has been published [10,21,[39][40][41]. The experimental procedure is described by Li et al [4,42].…”

“…Re-Os isotopic data have previously revealed that refractory lithospheric mantle can survive in orogenic peridotites, ophioliticperidotites and abyssal peridotites [10,12,17,18,20,21,[46][47][48][49][50]. Given the heterogeneous distribution of refractory domains in the asthenospheric mantle, it may be unsuitable to determine Os isotopic characteristics of the mantle source from analyses of mantle peridotites.…”

“…Subsequent to their formation, mantle peridotites may be modified by partial melting processes and interaction with melts percolating through them [14][15][16]. Recent studies indicate that refractory subcontinental lithospheric mantle (SCLM) can survive during the opening of ocean basins and become part of the oceanic lithosphere [10,[17][18][19][20][21][22]. Given the such preservation of refractory domains in ophiolitic mantle peridotites [6,8], their Re-Os isotopic characteristics cannot precisely reflect the nature of the convecting mantle at the time of ophiolite formation.…”

Orogenic, Ophiolitic, and Abyssal Peridotites

“…In addition, the Scandinavian garnet peridotites also record HT conditions ascribed to an earlier stage of mantle diapirism before their accretion to cratonic lithosphere (Brueckner et al, 2002Carswell and van Roermund, 2005;Drury et al, 2001;Spengler et al, 2006;van Roermund et al, 2001), and in such, they are somehow akin to the 'UHT' (ultrahigh-temperature) group (in the succeeding text). According to the recent studies of Shi et al (2010) and Xiong et al (2011), the Lü liangshan (or Shenglikou) garnet peridotite from the North Qaidam UHP belt in Eastern China may also be considered as 'relict' peridotites. 3.…”

The multi-stage tectonic evolution of the Xitieshan terrane, North Qaidam orogen, western China: From Grenville-age orogeny to early-Paleozoic ultrahigh-pressure metamorphism

“…The protolith of the garnet peridotite is still controversial and previously interpreted as an Alaskan type magmatic cumulate, formed at~460 Ma or a serpentinite that once formed part of an oceanic lithosphere (Song et al, 2005;Yang and Powell, 2008;Song et al, 2009a;Zhang et al, 2011b). In contrast, based on Re-Os isotope ages from sulfides collected from dunites inside the garnet peridotites, Shi et al (2010) interpreted the Lüliangshan garnet peridotite to represent an old Archean mantle fragment that was derived from the subcratonic lithosphere, but became refertilized in Neoproterozoic and/or early Paleozoic times. In the Yuka terrane coesite was discovered in eclogite; its occurrence is consistent with P-T conditions of 2.8-3.2 GPa and 650-700°C G.B.…”