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Introduction: Plant resources gathered from the wild are important sources of livelihood needs, especially for low-income populations living in remote areas, who rely on these plants for food, fuelwood, medicine and building materials. Yadong County is a valley at the border between the China, India and Bhutan in southern Tibet. Yadong is rich in biodiversity and culture, but ethnobotanical knowledge has not been systematically studied. This study aimed to document the ethnobotanical knowledge of Tibetans in Yadong County. Methods: Ethnobotanical data were documented through free listings, key informant interviews, and semi-structured interviews during fieldwork. The culture importance index (CI) and informant consensus factor index (FIC) were used as the quantitative indices. Results: In total, 163 informants (46 women and 117 men). A total of 3,031 use reports and 121 plant species belonging to 52 families and 91 genera were included. These use reports were then classified into 20 categories belonging to 9 major categories. The utilisation category that containing the most plant species was food, followed by economic, medicine, animal feed, social uses, other uses, environmental uses, materials and fuels. Among the economic plants, 32 medicinal plants are traditionally used in the local region. Plants with high CI included Fritillaria cirrhosa, Neopicrorhiza scrophulariiflora, Betula utilis, Rheum nobile, and Urtica hyperborean. Conclusion: This research demonstrates the diversity of the types and functions of Yadong Tibetan traditional plant knowledge. Knowledge of edible and medicinal plants in this area is prominent, reflecting the ability to cope with the lack of fruits and vegetables and basic family medical care. There were exchanges between the traditional plant culture in the study area and its surroundings. With socioeconomic development, the commercial value of medicinal plants has increased, and locals are also seeking ways to adoptsustainable development to cope with the excessive consumption of plant resources. [ABSTRACT FROM AUTHOR]

Late Mesozoic igneous rocks from the north Lhasa block record the Neo-Tethyan orogeny in the southern Tibet Plateau. This study presents geochronological and geochemical data of Bieruozecuo quartz diorite pluton in the northern margin of the Lhasa block to constrain its petrogenesis and tectonic implications. The LA–ICP–MS zircon U–Pb geochronology of quartz diorites shows that the emplacement occurs at ca. 114–116 Ma, belonging to the products of Early Cretaceous magmatic activities. The high concentrations of TiO2, MgO, and MnO, together with SiO2 vs. K2O and A/NK vs. A/CNK diagrams, all suggest that the Bieruozecuo quartz diorites are meta-aluminous and high-potassium calc-alkaline rocks. Their high Sr and low Y and Yb contents, as well as high Sr/Y and La/Yb ratios, are consistent with the typical adakitic rocks. The REE patterns show a large distribution of compositions, which have LREE, while HREE are buffered, along with large ratios of (La/Yb)N, as well as high values of K2O/Na2O, Mg#, Cr, and Ni, all of which imply the partial melting of a delaminated lower crust, without obvious fractional crystallization during the magma ascending and emplacement. This study suggests that, with the closure of the Bangonghu–Nujiang Tethys Ocean Basin, the post-collisional extension of the north Lhasa block will have started no later than ca. 114–116 Ma. Combined with the previous studies, our new data demonstrates that the partial melting of the delaminated lower crust, in a post-collisional setting, may be the main mechanism responsible for the ca. 116–82 Ma adakitic magmatism in the north Lhasa block. [ABSTRACT FROM AUTHOR]

Abstract: This study reports a dataset of 21 trace elements of magmatic zircons from typical I-type (93 analyses) and S-type (73 analyses) granitoids from the Lhasa and Himalayan terranes, southern Tibet, and A-type granitoids (21 analyses) from the Songpan–Ganzi terrane, eastern Tibet. Our results indicate that magmatic zircons from the I-type granitoids are characterized by relatively lower Pb concentrations and higher (Nb/Pb) N ratios, distinct from those of the S-type granitoids that reveal higher Pb, lower (Nb/Pb) N and significant Eu negative anomalies (Eu/Eu* ⩽0.3); while these values are transitional in zircons from the A-type granitoids. Such differences, most likely governed by compositional variations in the host magmas, are considered as a useful tool, in addition to U–Pb and Hf isotopes, for tracing the source provenance of detrital zircons. Consequently, the trace element compositions of detrital zircons with a diagnostic age peak (∼1170Ma) from the Lhasa Terrane indicate the presence of coeval S-type magmatism in their source region. This study exemplifies the usefulness of zircon trace element geochemistry in investigating sedimentary source provenance and paleogeographic reconstruction. [Copyright &y& Elsevier]