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LANG Xinghai LIU Dong DENG Yulin TANG Juxing XIE Fuwei YANG Zongyao CUI Zhiwei WANG Xuhui LI Zhijun ZHANG Zhong ZHANG Jinshu HUANG Yong 《《地质学报》英文版》2018,92(1):420-421
正Objective Lhasa terrane has recorded the geologic history concerning the formation and evolution of Paleo-Tethys and the intra-continental convergence in Qinghai–Tibet Plateau(Yin and Harrison,2000).Previous investigations have focused on the initial timing of the India-Asia collision and the Cretaceous–Cenozoic magmatism and sedimentation(Wang Tianyang et al.,2017),however, 相似文献
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成都“2008.9.24”暴雨的中尺度数值模拟 总被引：1，自引：0，他引：1
为了更好的研究四川成都地区2008年9月23日～25日强降水天气的物理机制,利用中尺度天气预报模式(Weather Research Forecast,WRF)模拟了此次过程,并结合FY-2号C星云图资料,对过程的发生、发展过程进行分析后发现,此次暴雨过程为低层弱低压辐合,同时台风"黑格比"登陆后带来大量水汽,并借助西伸的西太平洋副高源源不断的向四川盆地输送,另外存在来自南方孟加拉湾水汽的持续供应,对流云团形成于地面低压与西伸副高的交界处,并沿着副高边缘由西南向东北移动,雨带分布在副高边缘气压梯度大的地方,模拟结果与观测事实基本相符。利用WRF模式模拟暴雨产生的环流形势,配合卫星云图,能进一步揭示暴雨产生的物理机制,可作为深化暴雨研究的有效手段。 相似文献
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西藏冈底斯南缘汤白矿区早侏罗世含矿斑岩锆石U-Pb定年及其地质意义 总被引：1，自引：0，他引：1
汤白矿区位于西藏冈底斯斑岩铜矿带西段南缘,南侧紧邻日喀则弧前盆地。矿区由地表探矿工程控制3条赋存于早侏罗世角闪石英闪长斑岩中的主矿体(1号、2号和3号),在野外地质调查的基础上,对角闪石英闪长斑岩进行LA-ICP-MS锆石U-Pb定年和岩石地球化学测试。研究结果表明:(1)含矿斑岩的成岩年龄为183.3±1.2Ma,形成于早侏罗世;(2)含矿斑岩地球化学特征与大洋岛弧背景下的安山质岩石的地球化学性质一致,表明汤白矿区含矿斑岩形成于大洋岛弧环境;(3)西藏冈底斯斑岩铜矿带具有寻找俯冲期斑岩型矿床的巨大潜力,今后应加强该带俯冲期斑岩型矿床的勘查评价工作,特别是早—中侏罗世斑岩的成矿潜力评价。 相似文献
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The Zedong ophiolite is the largest ophiolite massif east of Dazhuqu in the Yarlung Zangbo Suture Zone in the southern Tibetan Plateau. However, its age, geodynamic setting and relationship to the Xigaze ophiolite remain controversial. New zircon U–Pb ages, whole-rock geochemical and Nd–Pb isotopic data from ophiolitic units provide constraints on the geodynamic and tectonic evolution of the Zedong ophiolite. U–Pb zircon geochronology of dolerite lavas and late gabbro–diabase dikes yield weighted mean ages of 153.9 ± 2.5 Ma and 149.2 ± 5.1 Ma, respectively. Strong positive εNd(t) and positive Δ7/4Pb and Δ8/4Pb values indicate derivation from a highly depleted mantle source with an isotopic composition similar to that of the Indian MORB-type mantle. The geochemistry of ophiolitic lavas and early dikes are analogous to typical island arc tholeiites whereas late dikes are similar to boninites. The geochemistry of these rock types suggests multi-stage partial melting of the mantle and gradually enhanced subduction influences to the mantle source through time. Combined with the MORB-like 162.9 ± 2.8 Ma Luobusha ophiolitic lavas, we suggest that the Luobusha lavas, Zedong lavas and early dikes originated in an infant proto-arc setting whereas late dikes in the Zedong ophiolite originated in a forearc setting. Together, they represent a Neo-Tethyan subduction initiation sequence. The Late Jurassic intra-oceanic proto-arc to forearc setting of the Zedong ophiolite contrasts with the continental margin forearc setting for the Xigaze ophiolite, which suggests a laterally complex geodynamic setting for ophiolites along the Yarlung Zangbo Suture Zone. 相似文献
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XIAO Changxi BAI Defeng Joseph P. LAMBERT LI Yibin Lhaba CERING GONG Ziling Philip RIORDAN SHI Kun 《资源与生态学报(英文版)》2022,13(3):483-500
The snow leopard (Panthera uncia) inhabits a human-altered alpine landscape and is often tolerated by residents in regions where the dominant religion is Tibetan Buddhism, including in Qomolangma NNR on the northern side of the Chinese Himalayas. Despite these positive attitudes, many decades of rapid economic development and population growth can cause increasing disturbance to the snow leopards, altering their habitat use patterns and ultimately impacting their conservation. We adopted a dynamic landscape ecology perspective and used multi- scale technique and occupancy model to better understand snow leopard habitat use and coexistence with humans in an 825 km2 communal landscape. We ranked eight hypothetical models containing potential natural and anthropogenic drivers of habitat use and compared them between summer and winter seasons within a year. HABITAT was the optimal model in winter, whereas ANTHROPOGENIC INFLUENCE was the top ranking in summer (AICcw≤2). Overall, model performance was better in the winter than in the summer, suggesting that perhaps some latent summer covariates were not measured. Among the individual variables, terrain ruggedness strongly affected snow leopard habitat use in the winter, but not in the summer. Univariate modeling suggested snow leopards prefer to use rugged land in winter with a broad scale (4000 m focal radius) but with a lesser scale in summer (30 m); Snow leopards preferred habitat with a slope of 22° at a scale of 1000 m throughout both seasons, which is possibly correlated with prey occurrence. Furthermore, all covariates mentioned above showed inextricable ties with human activities (presence of settlements and grazing intensity). Our findings show that multiple sources of anthropogenic activity have complex connections with snow leopard habitat use, even under low human density when anthropogenic activities are sparsely distributed across a vast landscape. This study is also valuable for habitat use research in the future, especially regarding covariate selection for finite sample sizes in inaccessible terrain. 相似文献
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Geothermal spring causes arsenic contamination in river waters of the southern Tibetan Plateau,China 总被引：1，自引：0，他引：1
Chaoliu Li Shichang Kang Pengfei Chen Qianggong Zhang Jue Mi Shaopeng Gao Mika Sillanpää 《Environmental Earth Sciences》2014,71(9):4143-4148
Large numbers of As-enriched geothermal springs are distributed at the southern Tibetan Plateau, and their influence on river water is still not clear. Lhasa River and its tributary, Duilong Qu located at downstream of the largest geothermal spring of the Tibetan Plateau, were selected for sampling during monsoon and non-monsoon seasons. Dissolved trace elements (B, Cr, Ni, Cu, Zn, As, Cs, Ba and U) were measured in river water samples by ICP-MS. The results show that due to contribution of geothermal spring, As levels of Duilong Qu (205.6 μg/L) and Lhasa River (12.7 μg/L) were higher during non-monsoon season than that of WHO guideline for drinking water (10 μg/L). Accordingly, As level of river water was lower during the monsoon season than that of the non-monsoon season due mainly to dilution process. Therefore, although Tibetan rivers are generally considered as free of contamination, geothermal springs cause As contamination of river water at some local regions and may harm the local residents. Further research is needed in other parts of the plateau to determine whether As level of groundwater of the related region is high. 相似文献
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Sharang is a low-fluorine, calc-alkaline porphyry Mo deposit hosted mainly in a granite porphyry of a multi-stage plutonic complex in the northern Gangdese metallogenic belt, largely with stockwork and ribbon-textured mineralization. The observed age estimates suggest that the formation of the magmatic host complex (52.9–51.6 Ma) and the ore deposit itself (52.3 Ma) occurred during the main stage of the India–Asia collision. The host rocks are characterized by lower zircon εHf(t) values than those of the pre-ore and post-ore rocks. This suggests that the Lhasa terrane basement might play an important role in the formation of Sharang ore-forming intrusions. In view of the framework of magmatic–metallogenic events we suggest that slab roll-back may have induced melting of juvenile crust and ancient continental complexes during the India–Asia collision. This proposal focuses exploration for additional molybdenum deposits on the collision zone. 相似文献
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基于西藏定日气象站1980~2019年逐月平均气温、0~20cm浅层地温资料，应用气候统计方法，分析了近40a定日浅层地温的变化特征。结果表明:40年来，定日各层（除5cm外）年平均地温均呈升温趋势，升温幅度为0.03~0.187℃/10a，0cm升温率最大，15cm升温率最小，5cm地温呈不明显的下降趋势，春、冬季各层地温升温最显著，除了0cm层外各层地温夏、秋季呈降温趋势；各层（除5cm外）年平均地温从2000s后均陆续发生突变现象，各层地温突变时间点不一致，但均是从相对偏冷期跃变为相对偏暖期，0cm和20cm在2000s前后明显发生了由冷变暖的转折；定日年平均气温升温率比各层地温都大，通过了0.01水平的显著性检验，其距平变化趋势和时段与各层地温相似，年平均气温与20cm层地温的相关性最显著；5cm地温与其他层次变化规律存在明显的差异。 相似文献