中条山地区郭家沟基性-超基性岩体的岩石成因及地质意义   总被引：1，自引：0，他引：1  

林伟 《地质与勘探》2016,52(6):1116-1128

文章通过对中条山地区郭家沟基性-超基性岩体的岩石学、矿物学和岩石地球化学方面的分析研究,讨论了该岩体的形成时代、岩石成因、及其地质意义。郭家沟岩体侵入时代为元古代,可能与绛县群形成时代较为相近(2200Ma左右)。郭家沟岩体具有岩相分带现象,边缘相为辉长岩,向内渐变过渡为含长辉石岩、变余辉石岩(角闪石岩)等,在岩体的中心发育着磁铁透闪石岩;岩石中Mg O与其他主量元素线性相关,各类岩石地球化学特征较为相似,显示出岩石受分离结晶作用的影响,具有岩浆同源演化的趋势;岩石总体显示出低硅、低镁、高铁、高钛、高钙的特征,相对富集LREE和LILE,而亏损HREE和Nb、Ta、Zr、Y等高场强元素,轻重稀土分馏明显,具有较弱的Eu异常,V含量较高,具有阿拉斯加型侵入岩体和与火山弧相关的岩浆特征。从岩石组合及地球化学特征结合区域构造演化,认为岩体形成于大陆边缘弧的构造环境,从侧面也说明绛县群的形成环境应该是大陆边缘俯冲后的伸展环境,而非陆内裂谷。  相似文献   

内蒙古达茂旗塔林宫地区找矿前景分析     

陈军强  李志丹  曾威  王佳营  高利军 《地质论评》2016,62(S1):21-22

内蒙古达茂旗塔林宫地区位于华北板块北缘与西伯利亚板块南缘的结合带,天山―兴蒙造山系之温都尔庙俯冲增生杂岩带(内蒙古自治区地质矿产局. 1991),白乃庙―哈达庙铜、金、萤石成矿带上(邵和明,张履桥. 2001) 。区域上矿产资源较为丰富,金属矿产主要有铁、稀土、金、铜等,非金属矿产主要有萤石、石灰岩、石英岩等,比较重要的矿床有白云鄂博钒钛稀土矿、查干哈达庙铜矿、乌花敖包金矿、赛乌苏金矿、白乃庙铜金矿、石宝铁矿等。  相似文献   

新疆三塘湖盆地牛圈湖区块异常低压成因及压力演化定量分析     

康媛  孙卫  盛军  时建超  刘艳妮  赵婷 《地质论评》2016,62(1):103-110

三塘湖盆地牛圈湖区块中生界侏罗系西山窑组储层具有典型的异常低压油藏特征,晚白垩末期储层达到最大埋深,此时下部芦草沟组烃源岩演化程度达到最大,随着油气持续向储层充注,此时地层压力达到最大,可达30.33~50.74MPa。本文从引起油藏异常低压的主要因素入手,定量分析了构造抬升与地层剥蚀、地层温度降低、成岩作用中的"耗水作用"以及矿物蚀变引起的自生体积缩小等因素对地层压力的影响。这些因素共同作用导致了地层压力降低,其中溶蚀作用中矿物蚀变所形成的"耗水作用",使地层压力下降24.4%~37.1%,是造成储层异常低压的首要因素,同时矿物蚀变导致自身体积缩小并导致储层压力下降16.5%~24.8%,地层温度降低和构造运动对储层压力降低影响相对较弱,降低幅度分别为7.9%~8.6%和4.8%~8.1%。以上种种因素的共同作用,使得地层压力下降17.45~37.85MPa,最终形成现今异常低压的分布格局。  相似文献   

Effects of Micro-structure and Micro-parameters on Brazilian Tensile Strength Using Flat-Joint Model     

Xueliang Xu  Shunchuan Wu  Yongtao Gao  Miaofei Xu 《Rock Mechanics and Rock Engineering》2016,49(9):3575-3595

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Evaluation of the Ground Response of a Pre-driven Longwall Recovery Room Supported by Concrete Cribs     

Hongpu Kang  Huawen Lv  Xiao Zhang  Fuqiang Gao  Zhigang Wu  Zhichao Wang 《Rock Mechanics and Rock Engineering》2016,49(3):1025-1040

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The impact of boreal autumn SST anomalies over the South Pacific on boreal winter precipitation over East Asia   总被引：1，自引：0，他引：1  

Juan AO  Jianqi SUN 《大气科学进展》2016,33(5):644-655

The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies(SSTAs) over the South Pacific Ocean(SPO) in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn,not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region.  相似文献   

Upper-Tropospheric Environment–Tropical Cyclone Interactions over the Western North Pacific: A Statistical Study     

Yu-Kun QIAN  Chang-Xia LIANG  Zhuojian YUAN  Shiqiu PENG  Junjie WU  Sihua WANG 《大气科学进展》2016,33(5):614-631

Based on 25-year(1987–2011) tropical cyclone(TC) best track data, a statistical study was carried out to investigate the basic features of upper-tropospheric TC–environment interactions over the western North Pacific. Interaction was defined as the absolute value of eddy momentum flux convergence(EFC) exceeding 10 m s~(-1)d~(-1). Based on this definition, it was found that 18% of all six-hourly TC samples experienced interaction. Extreme interaction cases showed that EFC can reach~120 m s~(-1)d~(-1) during the extratropical-cyclone(EC) stage, an order of magnitude larger than reported in previous studies.Composite analysis showed that positive interactions are characterized by a double-jet flow pattern, rather than the traditional trough pattern, because it is the jets that bring in large EFC from the upper-level environment to the TC center. The role of the outflow jet is also enhanced by relatively low inertial stability, as compared to the inflow jet. Among several environmental factors, it was found that extremely large EFC is usually accompanied by high inertial stability, low SST and strong vertical wind shear(VWS). Thus, the positive effect of EFC is cancelled by their negative effects. Only those samples during the EC stage, whose intensities were less dependent on VWS and the underlying SST, could survive in extremely large EFC environments, or even re-intensify. For classical TCs(not in the EC stage), it was found that environments with a moderate EFC value generally below ~25 m s~(-1)d~(-1) are more favorable for a TC's intensification than those with extremely large EFC.  相似文献   

Preface to the Special Issue “Unified Perspective of Climate Variability and Change”     

Shang-Ping Xie 《大气科学进展》2016,33(4):409-410

正Forty years ago,Klaus Wyrtki(1975)of University of Hawaii discovered that El Nino warming off South America is not a result of local wind change but a response to the relaxed equatorial trade winds some 10 000 km away near the international dateline.The Kelvin wave mechanism was quickly verified from wind-forced ocean model simulations.Consequent  相似文献   

Role of horizontal density advection in seasonal deepening of the mixed layer in the subtropical Southeast Pacific     

Qinyu Liu  Yiqun Lu 《大气科学进展》2016,33(4):442-451

The mechanisms behind the seasonal deepening of the mixed layer(ML) in the subtropical Southeast Pacific were investigated using the monthly Argo data from 2004 to 2012. The region with a deep ML(more than 175 m) was found in the region of(22?–30?S, 105?–90?W), reaching its maximum depth(～200 m) near(27?–28?S, 100?W) in September. The relative importance of horizontal density advection in determining the maximum ML location is discussed qualitatively. Downward Ekman pumping is key to determining the eastern boundary of the deep ML region. In addition, zonal density advection by the subtropical countercurrent(STCC) in the subtropical Southwest Pacific determines its western boundary, by carrying lighter water to strengthen the stratification and form a "shallow tongue" of ML depth to block the westward extension of the deep ML in the STCC region. The temperature advection by the STCC is the main source for large heat loss from the subtropical Southwest Pacific. Finally, the combined effect of net surface heat flux and meridional density advection by the subtropical gyre determines the northern and southern boundaries of the deep ML region: the ocean heat loss at the surface gradually increases from 22?S to 35?S, while the meridional density advection by the subtropical gyre strengthens the stratification south of the maximum ML depth and weakens the stratification to the north. The freshwater flux contribution to deepening the ML during austral winter is limited. The results are useful for understanding the role of ocean dynamics in the ML formation in the subtropical Southeast Pacific.  相似文献   

Competing impact of anthropogenic emissions and meteorology on the distribution of trace gases over Indian region     

Tabish U. Ansari  N. Ojha  R. Chandrasekar  C. Balaji  Narendra Singh  Sachin S. Gunthe 《Journal of Atmospheric Chemistry》2016,73(4):363-380

The spatial distribution of trace gases exhibit large spatial heterogeneity over the Indian region with an elevated pollution loading over densely populated Gangetic Plains (IGP). The contending role and importance of anthropogenic emissions and meteorology in deciding the trace gases level and distribution over Indian region, however, is poorly investigated. In this paper, we use an online regional chemistry transport model (WRF/Chem) to simulate the spatial distribution of trace gases over Indian region during one representative month of only three meteorological seasons namely winter, spring/summer and monsoon. The base simulation, using anthropogenic emissions from SEAC⁴RS inventory, is used to simulate the general meteorological conditions and the realistic spatial distribution of trace gases. A sensitivity simulation is conducted after removing the spatial heterogeneity in the anthropogenic emissions, i.e., with spatially uniform emissions to decouple the role of anthropogenic emissions and meteorology and their role in controlling the distribution of trace gases over India. The concentration levels of Ozone, CO, SO₂ and NO₂ were found to be lower over IGP when the emissions are uniform over India. A comparison of the base run with the sensitivity run highlights that meteorology plays a dominant role in controlling the spatial distribution of relatively longer-lived species like CO and secondary species like Ozone while short-lived species like NO_X and SO₂ are predominantly controlled by the spatial variability in anthropogenic emissions over the Indian region.  相似文献