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We have located a total of 232 local earthquakes using data recorded by the SANDWICH seismic network from November 2013 to October 2014 in central Tibet across the Bangong-Nujiang suture (BNS). The focal depths of all earthquakes are shallower than 30 km and therefore are in the upper crust. The absence of lower crust earthquakes may imply a weak, ductile lower crust in central Tibet. Moreover, these earthquakes are dispersed throughout conjugate strike-slip fault zones, indicating that evenly distributed upper crustal deformation might predominate in central Tibet. This observation agrees with the hypothesis that conjugate fault zones accommodate coeval east-west extension and north-south contraction via continuous deformation. Moreover, the focal mechanisms show that strike-slip and normal faulting are the dominant types of deformation and that the extension in central Tibet is oriented approximately east-west. Despite some anomalies, the kinematics implied by most of the focal mechanisms correlate well with those of the surface structures. [ABSTRACT FROM AUTHOR]

Abstract: Tectonic models for the evolution of the Himalayan orogen interpret the Greater Himalayan crystalline complex (GHC) to be the result of either thick-skinned thrusting involved Indian basement, thin-skinned thrusting involving exotic terranes, middle-crustal ductile flow, or wedge extrusion of the Indian crust during India–Asia collision. Two key pieces of information needed to test the validity of these models is the temporal–spatial distribution of, and the identification of the dynamic mechanisms involved in, regional melting under southern Tibet. Here, we document an Eocene–Oligocene melting event in southern Tibet, which forms a 150-km-long, NW–SE-trending granitoid belt along the Zedong–Lhunze traverse between the Indus–Yarlung suture (IYS) and the south Tibetan detachment (STD). U–Pb dating of magmatic zircons indicates that this granitoid belt youngs northward from ∼46Ma (in Lhunze) to ∼30Ma (in Zedong). 40Ar/39Ar dating of deformed biotite within 42–46Ma granitoids constrains the timing of shearing to ∼39–41Ma. The granitoid belt of southern Tibet is dominated by Eocene two-mica granites in the Tethyan Himalaya, with minor ∼30Ma granodiorites along the IYS and ∼35Ma granites in the Yelaxiangbo dome, where Indian mid-crustal rocks are exposed. The ∼35Ma granites are characterized by variable Na2O/K2O ratios (1.03–4.44), relatively high Sr concentrations, and high Sr/Y (14.0–126.3) and La/Yb (11.1–42.8) ratios, which distinguish these granitoids from Miocene leucogranites in the Himalaya. Comparison of the Sr–Nd isotopic compositions of these granites with mid-crustal amphibolites exposed in the Yelaxiangbo dome suggests that the granites were derived from melting of the amphibolites at ∼880°C and ∼10kbar. The ∼30Ma granodiorites and ∼42–46Ma two-mica granites are Na-rich and peraluminous, and are adakitic. They contain inherited Proterozoic zircons, and have a much wider range in ε Nd(t) of –14.9 to –2.5 and (87Sr/86Sr) i of 0.7062–0.7188, and have a Nd isotopic model age of 1486–1978Ma, indicating that these magmas were derived from a thickened Indian lower crust and were subsequently mixed with amphibolite-derived granite melts or were contaminated by the middle crust under southern Tibet. An apparent northward-younging age trend and shearing of the Eocene–Oligocene granitoids requires the southward migration of slices of middle crustal material, in which the Eocene granitoid magmas were emplaced and stored. Our data, along with structural, metamorphic, and intrusive histories of the Himalaya, lead us to propose a model for crustal anatexis and tectonic evolution of the Himalayan orogen, controlled by a number of large-scale events, such as slab break-off, buoyancy-driven uplift, lateral movement, and subsequent exhumation of slices of the subducted Indian crust during Indo-Asia collision at 55–40Ma. [Copyright &y& Elsevier]

Abstract: Bioenergy is the major domestic energy for rural households in developing countries due to its cheap or easy-getting characteristics. Productive use of bioenergy is an important strategy for rural households to improve not only their income, but also their health, living environment and so on. In Tibet of China, which is rich in cattle dung and firewood as the major energy sources for rural households, the efficiency of energy utilization is just about 10%. In order to improve energy utilization efficiency and the living conditions for rural residents, the Tibet Autonomous Region government introduced residential biogas model (RBM) to local households, which was a comprehensive utilization system of energy integrated with residential biogas digester, vegetable greenhouse and livestock shed. This paper aims to show the productive use of the bioenergy by the RBM, which could be depicted as the feasibility and the benefits on economic, eco-environmental and social aspects of biogas utilization, based on household questionnaires in Panam County. In RBM, biogas digester works as the biomass material supplement loop to transform originally biomass flow from single-direction to recycling-direction. The results indicate that the output of unit biogas digester could replace 1.44t of firewood, 1.65t of agricultural residues and 1.75t of cattle dung, respectively. The net incremental benefit of RBM could reach 5550.72 Yuan in 15 years. The reduced amount of CO2 emission when substituted by biogas in other agricultural areas and the areas of semi-agricultural and semi-husbandry in Tibet could be (76.66–79.89)×104 t/year and the capability for nitrogen storage could achieve (0.39–0.99)×104 t/year. The amount of cattle dung replaced by biogas could reach 78.29×104 t/year; this means that the saved cattle dung, 3.51t/hm2, could be reallocated back to cultivated land to improve the soil fertility and to keep the balance of nutrient elements in cultivated land. Biogas utilization reduces the labor opportunity costs of women compared to use of traditional bioenergy sources. It could be concluded that the productive use of bioenergy through RBM in this area has its capability to release the current pressures on biomass sources by adjusting patterns of rural energy consumption, and to improve the conditions of health, environment, economy and energy conservation. [Copyright &y& Elsevier]

In this study, a yeast-like fungal strain (LG-8), newly isolated from spontaneous Tibet kefir in China, was identified as Geotrichum candidum on the basis of its morphological characteristics and ITS5.8S gene sequence. Interestingly, the strain was able to remove more than 99% of Pb2+ ions in water at low concentrations and a maximum of 325.68 mg lead/g of dry biomass. The results of selective passivation experiments suggested that phosphate, amide and carboxyl groups on the cell wall contributed to lead removal. Scanning electron microscopy (SEM) photomicrographs revealed that large amounts of micro/nanoparticles formed on the cell wall, and energy dispersive X-ray spectroscopy (EDX) results further indicated the presence of lead along with phosphorus and chlorine in the particles. Furthermore, the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses revealed that the particles were composed of pyromorphite [Pb 5 (PO4) 3 Cl], a highly insoluble lead mineral. Importantly, this is the first time that the biomineralization of lead into pyromorphite has been observed as the major mechanism for lead removal by G. candidum LG-8, providing a new strategy to scavenge heavy metals from aquatic environment in an eco-friendly manner. Image 1 • A lead-tolerant Geotrichum strain LG-8 newly isolated from kefir milk was identified. • The strain removed at least 99% of lead from water with low lead levels. • Phosphate, amide and carboxyl groups are involved in lead removal. • Nanoparticles formed on cell wall surface. • Biomineralization of lead into pyromorphite is the major mechanism for lead removal. [ABSTRACT FROM AUTHOR]