湘西保靖县塘口湾水库岩溶渗漏分析

库区可能渗漏的岩溶形态,特别是岩溶负向形态的观测、钻孔和跨孔电磁波透视及CT层析成像揭示,库区的岩溶渗漏途径有所不同。根据控岩断裂的分布、岩溶发育强度和渗漏途径的变化特征,归纳为3种岩溶渗漏类型(方式): 断裂裂隙间溶裂系统(缝)渗漏,多发生在页岩与碳酸盐岩界面附近;小型溶隙(缝)孔洞渗漏,集中在500m 高程段上下;洞穴复合系统渗漏,主要在510m 高程上下。库区岩溶渗漏严重性由下而上增强。      

任意各向异性介质三维有限元航空电磁响应模拟

在航空电磁探测方法应用中,地下探测环境复杂,地下介质物性参数存在各向异性特征。如果采用常规各向同性介质模型,在资料解释过程中会产生严重的偏差。本文基于矢量有限元法开展三维任意各向异性频率域航空电磁响应模拟计算研究。首先,将总场分解成一次场和二次场,对空气介质的均匀全空间进行一次场解析计算,同时利用矢量有限元法对二次电场的双旋度方程进行求解。为提高求解速度,采用共享内存直接求解器PARDISO对大规模稀疏矩阵并行计算,大大提高了三维模型的计算速度。之后开展了4种典型目标模型的三维各向异性介质模拟：围岩各向同性-目标体各向异性（绕z轴旋转）模型;围岩各向同性-目标体各向异性（绕x轴旋转）模型;围岩各向异性-目标体各向异性（绕z轴旋转）模型;围岩各向异性-目标体各向异性（绕x轴旋转）模型。对比分析了不同模型在不同旋转角度情况下,磁场实虚分量的变化特征,进而总结了各向异性参数对航空电磁响应的影响规律和识别方法。     

空地异常组合特征分析与找矿

根据航空物探资料及地面查证（包括地质观察、地面磁法、电法、化探等）资料,探讨了空地异常组合特征与铁及多金属矿产的关系。在综合分析的基础上,初步建立了利用空地异常组合特征寻找铁及多金属矿的分析方法,对于今后利用空地综合方法确定找矿目标具有一定的指导意义。     

沁县七星泉天然矿泉水水质特征

沁县七星泉（后泉）饮用天然矿泉水是山西发现最早的天然矿泉水之一。１９８７年１１月经国家级鉴定为低钠、低矿化度、锶重碳酸－钙镁型饮用天然矿泉水。可作为瓶装天然矿泉水及矿泉饮料用水予以开发。     

Dynamic Relationship Between Entrainment Rate and Summer Monsoon in the Transition Area of Monsoon in the East of Northwest China

Entrainment rate refers to the ratio of surrounding air quality to air quality involved in rising unit distance, including turbulent entrainment and dynamic entrainment, which are applied to the boundary layer parametrization of convective clouds, the improvement of numerical model, the observation of cloud droplet spectral dispersion and the study of tropical cyclones.Based on the daily data at 07:00 and 19:00 every 10 m of five stations such as Minqin, Yuchong, Pingliang, Yinchuan and Yan'an from May to September during 2006-2016, combined with the daily observation data on the ground, the Entrainment Rates(ER) of different heights were calculated, and the relationships between ER and height in different regions, precipitation as well as monsoon during the monsoon period were further obtained. The main results were as follows:\mathrm{①} The ER was proportional to air temperature and saturated water vapor pressure, but inversely proportional to relative humidity. The relative humidity threshold of cloud was 65%. The higher the relative humidity threshold was, the lower the cloud height of different orders of precipitation was, and the cloud height was higher with the increase of rainfall. \mathrm{②}ER had obvious diurnal changes and regional differences: It was obviously smaller at 07:00 than at 19:00 from ground to 3 km, which weakened with the increase of height in the near surface , but strengthened with the increase of height above 500 m; From small to large, the monsoon affected area, the monsoon swing area and the non-monsoon area were in turn, and there was no regional difference above 3 km. \mathrm{③} ER was closely related to the intensity and property of precipitation in monsoon period. The ER weakened with the enhancement of rain intensity from near ground to below 600 m, but strengthened with the enhancement of rain intensity from 500 m to 2~3 km.From near ground to below 700 m, the ER of stable precipitation was strong, but that of convective precipitation was strong above 700 m. The convective precipitation had big saturated water vapor pressure and strong ER , while the stable precipitation had big saturated water vapor density, rich water vapor but weak ER. \mathrm{④}The relationship between ER and monsoon as well as its duration: From no monsoon to monsoon ER was weakened, the strongest maximum height was also decreasing. There was no significant difference in the duration of ER between the non-monsoon area and the monsoon affected area, but the longer the monsoon swing area lasted in the near ground layer, the smaller the ER was, while the opposite was at 1~2 km in the high altitude. \mathrm{⑤}The relationship between ER and the APO monsoon intensity index showed that: At 07:00, the ER strengthened with height from near ground to below 800 m, but weakened with height above 800 m,and the monsoon intensity was not related to the ER. At 19:00, the ER strengthened with the height near ground but weakened with the height above 300 m, and the stronger the monsoon was, the smaller the ER was. The ER weakened with the decrease of boundary layer height.     

西藏措勤晚白垩世英安岩的厘定与地球化学特征

野外地质调查和SHRIMP锆石U/Pb地质年代学研究表明,拉萨地块中带措勤地区发育一套形成于晚白垩世中期的英安岩(88.5±1.2 Ma)。该套火山岩具有岛弧火山岩的地球化学特征,为地壳深部岩浆岩部分熔融形成的Ⅰ型岩浆岩,经历了明显的斜长石分离结晶作用。与同时代的侵入岩相比,该套火山岩为高度演化的岩浆,Rb/Sr比值较高,但Sr/Y比值较低。在拉萨地块内部,广泛发育的90～85 Ma的岩浆作用与新特提斯洋的北向俯冲作用相关。     

Advances in Oxygenation Theory and Technology in Deep Lakes

Deep lakes always maintain vertical thermal stratification due to their physical structure. The thermocline prevents the transfer of oxygen from epilimnion to hypolimnion, leading to the formation of anoxic conditions in deeper water, the enhanced release of endogenous pollutants and the deterioration of water quality. Oxygenation is an effective measure to improve the water quality of deep lakes and mitigate the release of endogenous pollutants via the increase of the oxygen level in water. This paper provided an overview of the method and theory of oxygenation in deep lakes. Advantages and limitations of different methods of oxygenation, including artificial destratification, airlift aerators, Speece cone and bubble plume diffusers, were discussed. In addition, challenges and prospects of oxygenation were assessed based on the analyzing of typical examples of oxygenation in deep lakes and the difference in oxygenation system used in deep lakes and shallow lakes.     

An Review of International Climate Change Conference and Analysis on Recent Hot Issues

The international climate change negotiation has been carried out over 20 years. The issue of climate change has shifted from a scientific question into a complex political matter which is related to the sustainable development of mankind. Based on the overview of major processes and stages of international climate conferences, this paper analyzed the key measures that major countries have taken to address climate change, as well as the primary tasks of Paris climate conference and recent international actions. The recent international climate policy issues were also analyzed in order to provide suggestions for China’s activel participation in the development of a new round of international climate change system.     

Lamproitic Rocks from a Continental Collision Zone: Evidence for Recycling of Subducted Tethyan Oceanic Sediments in the Mantle Beneath Southern Tibet

Major and trace element, Sr–Nd–Pb isotope and mineralchemical data are presented for newly discovered ultrapotassiclavas in the Tangra Yumco–Xuruco graben in southern Tibet.The ultrapotassic lavas are characterized by high MgO, K₂O andTiO₂, low Al₂O₃ and Na₂O contents, and also have high molarK₂O/Al₂O₃, molar (K₂O + Na₂O)/Al₂O₃ and K₂O/Na₂O ratios. Theirhigh abundances of incompatible trace elements such as largeion lithophile elements (LILE) and light rare earth elements(LREE) reach the extreme levels typical of lamproites. The lamproitesshow highly radiogenic ⁸⁷Sr/⁸⁶Sr (0· 7166–0·7363) and unradiogenic ¹⁴³Nd/¹⁴⁴Nd (0· 511796–0·511962), low ²⁰⁶Pb/²⁰⁴Pb (18· 459–18· 931),and elevated radiogenic ²⁰⁷Pb/²⁰⁴Pb (15· 6732–15·841) and ²⁰⁸Pb/²⁰⁴Pb (39· 557–40· 058) ratios.On the basis of their geochemical and isotopic systematics,the lamproites in south Tibet have a distinct magma source thatcan be differentiated from the sources of potassic lavas inthe east Lhasa and Qiangtang blocks. Their high Nb/Ta ratios(17· 10–19· 84), extremely high Th/U ratios(5· 70–13· 74) and distinctive isotope compositionsare compatible with a veined mantle source consisting of partialmelts of subducted Tethyan oceanic sediments and sub-continentallithospheric depleted mantle. Identification of the lamproitesand the delineation of their mantle source provide new evidencerelevant for models of the uplift and extension of the Tibetanplateau following the Indo-Asia collision. Metasomatism by partialmelts from isotopically evolved, old sediment subducted on theyoung Tethyan slab is an alternative explanation for PrecambrianNd and Pb model ages. In this model, differences in isotopiccomposition along-strike are attributed to differences in thetype of sediment being subducted, thus obviating the need formultiple metasomatic events over hundreds of million years.The distribution of lamproites, restricted within a north–south-trendinggraben, indicates that the initiation of east–west extensionin south Tibet started at 25 Ma. KEY WORDS: lamproites; subducted oceanic sediment; Tibetan active continental collision belt