Re-Os geochronology of Cu and W-Mo deposits in the Balkhash metallogenic belt,Kazakhstan and its geological significance

<正>The Central Asian metallogenic domain(CAMD) is a multi-core metallogenic system controlled by boundary strike-slip fault systems.The Balkhash metallogenic belt in Kazakhstan,in which occur many large and super-large porphyritic Cu—Mo deposits and some quartz vein- and greisen-type W—Mo deposits,is a well-known porphyritic Cu—Mo metallogenic belt in the CAMD.In this paper 11 molybdenite samples from the western segment of the Balkhash metallogenic belt are selected for Re—Os compositional analyses and Re—Os isotopic dating.Molybdenites from the Borly porphyry Cu deposit and the three quartz vein-greisen W—Mo deposits—East Kounrad.Akshatau and Zhanet—all have relatively high Re contents(2712—2772μg/g for Borly and 2.267—31.50μg/g for the other three W—Mo deposits),and lower common Os contents(0.670—2.696 ng/g for Borly and 0.0051—0.056 ng/g for the other three).The molybdenites from the Borly porphyry Cu—Mo deposit and the East Kounrad,Zhanet,and Akshatau quartz vein- and greisen-type W—Mo deposits give average model Re—Os ages of 315.9 Ma,298.0 Ma,295.0 Ma,and 289.3 Ma respectively.Meanwhile,molybdenites from the East Kounrad,Zhanet,and Akshatau W—Mo deposits give a Re—Os isochron age of 297.9 Ma,with an MSWD value of 0.97.Re-Os dating of the molybdenites indicates that Cu—W—Mo metallogenesis in the western Balkhash metallogenic belt occurred during Late Carboniferous to Early Permian(315.9—289.3 Ma),while the porphyry Cu—Mo deposits formed at—316 Ma,and the quartz vein-greisen W—Mo deposits formed at ~298 Ma.The Re—Os model and isochron ages thus suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism took place during the late Hercynian movement.Compared to the Junggar-East Tianshan porphyry Cu metallogenic belt in northwestern China,the formation of the Cu—Mo metallogenesis in the Balkhash metallogenic belt occurred between that of the Tuwu-Yandong in East Tianshan and the Baogutu porphyry Cu deposits in West Junggar. Collectively,the large-scale Late Carboniferous porphyry Cu—Mo metallogenesis in the Central Asian metallogenic domain is related to Hercynian tectono-magmatic activities.     

广西沿海超高层建筑进行气象灾害风险评估必要性

通过列举国内外超高层建筑遭受气象灾害的案例,结合广西气象灾害风险区划资料,分析大风、台风、龙卷风、暴雨、雷电（雷击）、强降温等灾害与沿海超高层建筑的关系,以及可能造成的影响和潜在的风险,论述了超高层建筑进行气象灾害风险评估可实现最大安全与最小投资的统一.以期为广西沿海开展“超高层建筑气象灾害风险评估”工作提供理由和依据.     

隆林县近53年气温变化特征分析

利用隆林县1958～2010年气温观测资料,应用统计方法分析隆林县近53a来气温变化特征。结果表明：隆林县年平均气温、年平均最低气温、极端最高气温、极端最低气温、四季平均气温均呈上升趋势,尤其以秋、冬季较为明显。     

广西气象部门用友A＋＋财务管理软件系统之研究

用友A＋＋财务管理软件系统是气象部f-j2009年新推出的财务管理软件,较之以前使用的财务管理系统新增加了许多功能。通过对这一系统的研究,把握了高效使用该系统的方法,同时提出了进一步完善A＋＋财务管理系统的看法。     

基于FY-3A／MERSI的洪涝灾害遥感监测初探

介绍了FY-3A/MERSI数据的基本情况,利用MERSI数据1～5通道进行典型地物的光谱分析了典型地物在MERSI图像上的特点和水体识别模型,选择适用于MERSI图像的模型对2008年10月南宁市发生的洪涝灾害进行监测.     

Understanding Agriculture Production and Food Security in Ethiopia from the Perspective of China

Food security and sustainable agricultural development are the hot issues of scientific research, especially after the population affected by hunger surprisingly increased in 2016. Long-lasting and recurrent famines caused by natural disasters and wars have afflicted Ethiopia. Unlike Ethiopia, which is still struggling to achieve food self-sufficiency, China managed to quickly become food self-sufficient at a rapid speed, despite the fact that it also faced the same challenges of famine over the last century. In the backdrop of differing environmental and socio-political challenges the two countries face, comparing the similarities and differences between the two countries will yield important lessons and insights for Ethiopia to follow to achieve food self-sufficiency. Here, the progress towards food security in Ethiopia and China is presented to quantitatively compare the gap of agricultural production between both countries. We found that food production in Ethiopia is heavily constrained by drought, soil degradation, climate change, out-dated agricultural production technologies, and poverty. According to these challenges, we examined corresponding responses in China to propose solutions for achieving food self-sufficiency in Ethiopia, given the realities of its unique national situation.     

高温高压下成矿元素运移聚集模拟实验

通过不同温度和压力下岩块受力变形的模拟实验,证实了岩块受力变形导致成矿元素的迁移和富集,发现了高温高压下不同元素在同一温压条件下和同一元素在不同温压条件下具有不同的迁移和富集规律。实验表明,构造应力对许多内生金属矿产的形成、矿产中成矿元素的分带现象等都具有十分重要的作用。      

Source-independent wave-equation based microseismic source location using traveltime inversion

A new source location method using wave-equation based traveltime inversion is proposed to locate microseismic events accurately. With a sourceindependent strategy, microseismic events can be located independently regardless of the accuracy of the source signature and the origin time. The traveltime-residuals-based misfit function has robust performance when the velocity model is inaccurate. The new Fréchet derivatives of the misfit function with respect to source location are derived directly based on the acoustic wave equation, accounting for the influence of geometrical perturbation and spatial velocity variation. Unlike the mostly used traveltime inversion methods, no traveltime picking or ray tracing is needed.Additionally, the improved scattering-integral method is applied to reduce the computational cost. Numerical tests show the validity of the proposed method.     

火电厂粉煤灰的矿物磁性及其环境意义

火电厂排放的粉煤灰是重要的大气颗粒污染物之一,利用粉煤灰的磁性监测环境污染是新近发展的新手段。应用矿物磁测技术和X射线衍射对浙江省主要电厂排放的粉煤灰的矿物磁性特征和磁性矿物学,以及与重金属元素的关系进行了研究,结果表明粉煤灰具有较高的磁化率（X）、软剩磁（IRM20mT）和饱和等温剩磁（SIRM）值,粉煤灰频率磁化率（Xfd）的平均值为2．5％,磁性矿物以多畴（MD）颗粒存在,粉煤灰的剩磁矫顽力（BCR）在42～53mT之间。矿物测试结合X射线衍射分析表明粉煤灰中的氧化铁矿物以FeO4和Fe2O3-α为主,粉煤灰的磁化率与Fe、Mn、Pb、Zn、Cu、CA含量呈显著线性正相关,相关系数（r）分别是0．924,0．866,0．725,0．756,0．945和0．867,磁化率可作为粉煤灰中重金属元素含量的代用指标。