Zircon U–Pb Dating and Geochemistry of the Linong Granitoid and Its Relationship to Cu Mineralization in the Yangla Copper Deposit,Yunnan, China

The Yangla copper deposit (Cu reserves: 1.2 Mt) in the Jinshajiang–Lancangjiang–Nujiang region in China is spatially associated with the Linong granitoid. Zircon U–Pb dating shows the granitoid formed at 234.1 ± 1.2 to 235.6 ± 1.2 Ma, and the KT2 ore body of the deposit yields a molybdenite Re–Os model age of 230.9 ± 3.2 Ma. The ages of mineralization and crystallization of the granitoid are identical within the measurement uncertainties, suggesting the Yangla deposit is genitically related to the Indosinian Linong granitoid.     

The mesoscale balance and imbalance and the corresponding potential vorticity inversion from the view of helicity

The static balance and the geostrophic balance are the common balances in meteorology.All the synoptic systems and most of the mesoscale systems satisfy the above two balances.However,due to the strong convection and non-geostrophic feature,many mesoscale systems usually present as static imbalance,and the quasi-geostrophic approximation is no longer attainable.This paper tried to find out a kind of balance that exists for mesoscale convective system.To do this,the concrete mathematics definitions for balance and imbalance equations were defined.Then,it is proposed that the new balance equation should include the divergence,vorticity,and vertical motion simultaneously,and the helicity equation was a good choice for the basis.Finally,the mesoscale balance and imbalance equations were constructed,as well as a new balance model that was based on the helicity,horizontal divergence,vertical vorticity,continuity,and thermal dynamic equations under same approximations.Moreover,the corresponding potential vorticity(PV)inversion technique was introduced.It was pointed out that by using the PV conservation and the potential temperature conservation,the flows of the mesoscale balance model can be deduced,and their comparison with the real fields would give the degree of the imbalance.     

贺兰山北段牛头沟金矿床成矿流体和成矿物质来源:来自H-O-S-Pb同位素的证据

贺兰山北段牛头沟金矿床为华北克拉通西北缘新发现的金矿床,包括构造破碎带蚀变岩型和石英脉型两种矿化类型,后者可进一步细分为低缓石英脉型和陡窄石英脉型2个亚类。矿区所有矿体均赋存在古元古界贺兰山群变质杂岩和混合花岗岩内,受主干断裂F_1及其上盘次级断裂体系控制。综合本文及前人研究成果表明,破碎带蚀变岩型石英流体包裹体以纯液相水溶液包裹体为主,而低缓石英脉型和陡窄石英脉型石英流体包裹体则以气液两相水溶液包裹体为主,不同矿化类型成矿流体均为中低温(160~210℃)、中低盐度(6%~12%NaCl_(eq))的H_2O-NaCl流体。对矿区内3种矿化类型石英流体包裹体和硫化物分别开展的H-O和S-Pb同位素研究显示:破碎带蚀变岩型和陡窄石英脉型流体包裹体δD_(H2O)组成相近,分别为-75.2‰~-89.3‰和-87.0‰~-93.8‰,而低缓石英脉型流体包裹体则具有较高的δD_(H2O)值(-45.7‰~-67.7‰);流体包裹体δ~(18)O_(H2O)值则由破碎带蚀变岩型(3.7‰~4.4‰)→低缓石英脉型(1.9‰~3.3‰)→陡窄石英脉型(0.5‰~0.9‰)依次降低。破碎带蚀变岩型和陡窄石英脉型δ~(34)S组成均为正值,分别为1.3‰~6.9‰和2.2‰~5.8‰,而低缓石英脉型则具有较低的δ~(34)S值(-5.1‰~-2.6‰)。低缓石英脉型金矿具有明显不同的δD_(H2O)和δ~(34)S组成,可能与含矿断裂性质及其距离导矿构造F_1断裂较远等因素所共同导致的成矿流体氧逸度升高有关。3种矿化类型对应的矿石均表现出明显富集Th放射成因Pb的特点,~(206)Pb/~(204)Pb(16.467~17.994)和~(207)Pb/~(204)Pb(15.382~15.582)组成相对均一,而~(208)Pb/~(204)Pb变化较大(37.413~42.345)。总体上,石英流体包裹体H-O同位素组成表明成矿流体均为岩浆水和大气降水形成的混合流体,其大气降水比例自破碎带蚀变岩型→低缓石英脉型→陡窄石英脉型依次升高;矿石S-Pb同位素指示成矿物质为深部岩浆和具有高Th/U比的基底围岩双重来源。结合区域构造–岩浆演化,笔者将牛头沟金矿床成矿过程概括为晚古生代裂陷盆地形成阶段、中晚侏罗世区域挤压推覆阶段和晚侏罗世至早白垩世岩浆热液活动阶段等3个阶段。     

Distinct quasi-biweekly features of the subtropical East Asian monsoon during early and late summers

Using Global Precipitation Climatology Project daily rainfall and ERA interim reanalysis data, we investigate the distinct characteristic of quasi-biweekly variation (QBV: 12–20 days) over East Asia (EA) during early (June 10–July 20) and late (July 21–August 31) summer. The QBV maximum variance is found over the core region of EA (30°–40°N, 110°–130°E), which includes eastern China (lower reaches of the Yellow, Huaihe, and Yangtze rivers) and the Korean Peninsula. At both its peak wet and dry phases, QBV over the core region has a baroclinic structure, but with different spatial distributions, different lower-level prevalent wind anomalies, and different upper-level major circulation anomalies in the two subseasons. Meanwhile, the two subseasons have different propagating tracks prior to reaching the peak phase, and different precursors associated with the local genesis of QBV. Furthermore, during the transition from the peak dry to peak wet phase of QBV, the major monsoon circulations have different behaviors that tropical monsoon trough extends eastward in early summer but retreats westward in late summer and the South Asia high (SAH) and western North Pacific (WNP) subtropical high move toward (away from) each other in early (late) summer. The abrupt change of mean state in mid to late July, which includes the northward migration of westerly jet, SAH and WNP, and the weakening and broken of westerly jet, is considered the root cause of the change in behavior of QBV. Finally, we indicate that the tropical monsoon trough and midlatitude westerly jet are possible sources of QBV over subtropical EA in both subseasons and provide useful guidance for 2–3 week predictions over EA.     

寻找相似天气过程的一种数学模型

该文介绍了一种寻找相似天气过程的数学模型，利用Saaty论述的方法[1]构造判别矩阵进行判别，从而计算出相似排序及相似度。该方法在3年多的预报业务中应用，效果良好。     

Single epoch GPS deformation signals extraction and gross error detection technique based on wavelet transform

IntroductionGPS technique is widely used for deformationmonitoring thanks for the high precision. Usual-ly , there are three working modes associatedwith GPS deformation observation: periodicalGPS deformation monitoring net , GPS monito-ring array and rea…     

海上油井密封套管内海水冻胀特性试验分析

1998年首次进行了海上油井密封套管内海水冻胀特性模拟试验,建立了一套各种参数的测量系统.文中介绍了管内海水冻结过程、海水过冷温度、结冰水温、轴向冻胀力以及管体应变测量结果.     

古尔班通古特沙漠大气边界层参数化方案的模拟评估[1]

为准确描述我国最大的固定/半固定沙漠-古尔班通古特沙漠区域的大气边界层结构,本文利用该沙漠腹地2017年的梯度铁塔和通量观测数据,基于中尺度气象模式WRF (Weather Research and Forecast v3.7.1),分析了5种边界层参数化方案在古尔班通古特沙漠的适用性。结果表明：1）采用WRF模拟沙漠腹地近地层内的边界层特征时,2m气温的模拟存在冷偏差,5种边界层参数化方案均能较好地模拟出四个季节2m气温的日变化特征,其中非局地方案ACM2(Asymmetric Convective Model version 2)对2m气温效果最好,局地方案BL方案的模拟偏差最大;2）5种边界层参数化方案均能够模拟出10m风速的日变化特征,其中局地方案BL(Bougeault-Lacarrere)对10m风速效果最佳;3）采用WRF模拟沙漠近地层内的地表通量特征时,感热通量存在高估现象,潜热通量存在低估现象,5种边界层参数化方案均能较好地模拟出四个季节模拟时间段内地表净辐射通量的日变化特征,其中局地方案MYJ(Mellor-Yamada-Janjie)的模拟精度最高。     

An elastoplastic damage constitutive model for concrete

An elastoplastic damage constitutive model to simulate nonlinear behavior of concrete is presented. Similar to traditional plastic theory, the irreversible deformation is modeled in effective stress space. In order to better describe different stiffness degradation mechanisms of concrete under tensile and compressive loading conditions, two damage variables, i.e., tension and compression are introduced, to quantitatively evaluate the degree of deterioration of concrete structure. The rate dependent behavior is taken into account, and this model is derived firmly in the framework of irreversible thermodynamics. Fully implicit backward-Euler algorithm is suggested to perform constitutive integration. Numerical results of the model accord well with the test results for specimens under uniaxial tension and compression, biaxial loading and triaxial loading. Failure processes of double-edge-notched (DEN) specimen are also simulated to further validate the proposed model.     

地下导线随盾构推进逐段接测中的可靠性检验

盾构法施工的要点是需要在井下布设高精度的控制支导线，当我们根据盾构推进进度对导线接测时，由于观测条件、观测方法、观测仪器基本相同，但观测、的成果往往会存在一定的差异，有时我们无法直接判断成果的正确与否，此时，采用测量平差中的统计检验的方法来分析这些观测数据，可以取得比较满意的结果。