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The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane. Its petrogenesis and tectonic setting have been studied for decades, but remain controversial. Here we report data on geochronology, geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith, which provide more evidence to uncover its petrogenesis and regional geodynamic processes. The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I‐type, S‐type and highly fractionated granites. The I‐ and S‐type granites exhibit medium SiO2, high K2O/Na2O with negative εNd(t) and εHf(t) values, whereas, the albite granites have very high SiO2 (79.04%–80.40%), very low K2O/N2O, negative εNd(t) and a large variation in εHf(t). Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area. The granodiorites involved had a hybrid origin from partial melting of basalt‐derived and Al‐rich rocks in the crust, the porphyritic monzogranites being derived from partial melting of pelitic rocks. The albite granites crystallized from residual melt separated from K‐rich magma within the 'mush' process and underwent fractionation of K‐feldspar. We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward‐subducting slab of the NTO. [ABSTRACT FROM AUTHOR]

Kumbum Monastery is the centre of Tibetan Buddhism and religious culture in Qinghai. Its palace buildings are the typical examples of Tibetan Buddhist monastery buildings and living fossils of Tibetan social history. This study selected 12 palace buildings of Kumbum Monastery as the study objects, used typological approaches and numerical method to analyse their spatial features, classified these features into four types (the ring road surrounding Dugang-style palace space, single-sided eaves of the Duguang-style palace space, three-stage palace space with cloisters connecting to Dugang, and other variants) according to their spatial structures, and discussed the temporal evolution of the spatial features from spatial and temporal perspectives to obtain the development process for the palace buildings of Kumbum Monastery. The analysis showed that: 1) Because the Han people migrated to Qinghai, the architectural space of the monastery followed the practices of Tibet in the same period and began to adopt the practices of the Han people under the effect of religious indoctrination and sociopolitical influence of the Ming dynasty. 2) Due to the influence of religious development facilitated by the political environment in the Qing dynasty, all the palace buildings of Kumbum Monastery adopted the practice of monasteries in Lhasa. After being implicated by the political rebellion, the monastery initiated to add the spatial layout elements of the buildings in Qinghai. Therefore, the monastery was obtaining the cues from the Han culture. 3) The dominance of religious significance over the spatial designing of the palace buildings of Kumbum Monastery gradually shifted to the political dominance. This paper revealed the spatial and temporal features and evolution of the palace building space, explored the generation process of the palace buildings space of Tibetan Buddhist monasteries in Qinghai, and provided a reference for the static conservation and dynamic development of Tibetan Buddhist monastery buildings in Qinghai. [ABSTRACT FROM AUTHOR]

Recent advances in analytical techniques have achieved high-precision (2σ ≤ 0.06‰) determinations of Mo isotopic ratios in silicate rocks but few such data are as yet available, especially for low-Mo (<50 ppb) rocks such as leucogranites. Here we present two low-blank, double-spike, high-yield, ion-exchange chromatographic methods (single- and two-column) for precise determination of Mo isotopic ratios in low-Mo rock samples (10–500 ppb) using multicollector–inductively coupled plasma–mass spectrometry (MC–ICP–MS). The two-column technique involved AG 1-X8 anion-exchange (100–200 mesh) and BPHA chelatin resins, with the latter also used in the single-column procedure. Two USGS reference materials (basalt BIR-1a and diabase W-2a) were analyzed for quality-control purposes. Their δ98/95Mo values determined using the two methods are consistent within uncertainties, and with those determined by previously published methods. We provide the first Mo isotopic data for the reference materials of dunite DTS-2b (USGS), GPt-3 (NRCG) and peridotite WPR-1 (CCRMP). δ98/95Mo values for DTS-2b and WPR-1 by using two-column procedure are in good agreement with those obtained by single-column separation. Repeated analyses of these standards indicate a long-term external reproducibility of better than ±0.05‰. However, the δ98/95Mo values of GPt-3 show poor reproducibility due to either the sample heterogeneity or existing undigested minerals (e.g., spinel). The methods were applied to leucogranites with low Mo contents of 10–74 ppb from the Himalaya orogen and southern Lhasa terrane of Tibet. The isotopic analyses yielded δ98/95Mo values of −0.2‰ to 0.34‰ and −0.41‰ to −0.68‰ (against NIST SRM 3134), respectively, within the range of values for igneous crust. Their contrasting Mo isotopic compositions may indicate compositional diversity in their sources or differences in magma evolution. • Two methods (single- and two-column) were proposed to analyze δ98/95Mo of ppb-level rock samples by MC-ICP-MS. • The methods significantly enhance time efficiency and achieve low blank and high external precision for Mo separation. • We reported new data for the reference materials of DTS-2b (USGS), WPR-1 (CCRMP) and GPt-3 (NRCG). • The methods achieve measurements of the leucogranites from the Tibet, which have Mo contents of 10–74 ppb. [ABSTRACT FROM AUTHOR]