A perspective view on ultrahigh-pressure metamorphism and continental collision in the Dabie-Sulu orogenic belt

The study of continental deep-subduction has been one of the forefront and core subjects to advance the plate tectonics theory in the twenty-first century. The Dabie-Sulu orogenic belt in China crops out the largest lithotectonic unit containing ultrahigh-pressure metamorphic rocks in the world. Much of our understanding of the world＇s most enigmatic processes in continental deep-subduction zones has been deduced from various records in the Dabie-Sulu rocks. By taking these rocks as the natural laboratory, earth scientists have made seminal contributions to understanding of ultrahigh-pressure metamorphism and continental collision. This paper outlines twelve aspects of outstanding progress, including spatial distribution of the UHP metamorphic rocks, timing of the UHP metamorphism, timescale of the UHP metamorphism, the protolith nature of deeply subducted continental crust, subduction erosion and crustal detachment during continental collision, the possible depths of continental subduction, fluid activity in the continental deep-subduction zone, partial melting during continental collision, element mobility in continental deep-subduction zone, recycling of subducted continental crust, geodynamic mechanism of postcollisional magmatism, and lithospheric architecture of collision orogen. Some intriguing questions and directions are also proposed for future studies.     

缺货量部分拖后订货的易变质物品的库存模型

研究了时变需求下,缺货量可以部分拖后订货的易变质物品的库存问题.有关易变质物品的库存问题研究,往往假设未被满足的需求可以全部拖后订货,同时在计算总成本时忽视了销售损失成本和采购成本,这导致模型与实际情况具有较大的差距.在总成本中计入销售损失成本和采购成本,通过假定未被满足的需求拖后订货率线性取决于缺货周期内排队等待的队伍中总的顾客数目,并将物品的常数需求函数扩展到时变凹函数,建立了有限时域内易变质物品的补货时间安排模型.给出了求解模型的算法和数值算例,得到最优订购策略.     

北大别山adakite型灰色片麻岩的确定及其与超高压变质作用的关系

研究发现北大别山中酸性灰色片麻岩中存在ａｄａｋｉｔｅ型岩石,其地球化学特征表现同Ａ１２Ｏ３,Ｓｒ,Ｓｒ／Ｙ和Ｌａ／Ｙｂ,低Ｙ,Ｙｂ和Ｓｃ,Ｓｒ正异常,铕正异常或微弱负异常,北大别山ａｄａｋｉｔｅ型灰色片麻岩由俯冲大洋板片融形成,已有的研究表明大别山灰色片麻岩主要分布于大别山且形成于印支期前,因此北大别山ａｄａｋｉｔｅ型灰色片麻岩的存在扬子和华北板块印支期碰撞前存在大洋板片的俯冲,洋壳是向北大别山下     

辽河断陷下第三系烃源岩有机质Pb和Sr同位素研究

报道了辽河断陷下第三系烃源岩有机质（干酪根,可溶有机质）的Ｐｂ,Ｓｒ同位素组成,干酪根的Ｐｂ同位纱组成有很大的变化范围,＾２０６Ｐｂ／＾２０４Ｐｂ＝１７．４８８～１８．６５６,＾２０７Ｐｂ／＾２０４Ｐｂ＝１５．３８８～１５．６９２,＾２０８Ｐｂ／＾２０４Ｐｂ＝３７．６５６～３７．７４８,可溶有机质具有相当稳定的Ｐｂ同位素组成：＾２０６Ｐｂ／＾２０４Ｐｂ＝１７．４２４～１７．６０１,＾２０７Ｐｂ／＾     

铝箔粗轧过程中黑色散油点的成因与对策

介绍了铝箔粗轧过程中黑色散油点的表现形式和产生机理,对其影响因素进行了综合分析.通过引进岗位竞争激励长效机制,提高员工的产品质量责任意识;进行设备改造,加装和固定挡油、导流、三次吹扫装置,合理的调节轧制线高度和轧制出口排烟能力,发挥中间吹扫、中间接油板、边部辊缝吹扫、板面吹扫的作用,减少轧制带油;严格控制铝箔坯料内在冶金质量,减少轧制脱粉;加强工艺油品管理,预防轧制油品老化变质;搞好文明生产,定期清洁轧机.有效地减少了铝箔粗轧箔材表面黑色散油点缺陷的发生.     

中国浅成低温热液型金矿床地质特征及研究现状

浅成低温热液型金矿床早已经成为了金矿研究的热门矿床,也逐渐变成了世界上最为重要的金矿床类型中的一种。它的发展受到了很多自然环境和条件的限制,也通过这些限制获得了更多的发展前景,中国在这一方面具有比较好的优势。     

Molybdenum isotopic composition as a tracer for low-medium temperature hydrothermal ore-forming systems: A case study on the Dajiangping pyrite deposit,western Guangdong Province,China

Little is known about the range or controls on the molybdenum isotopic composition of low-medium temperature hydrothermal ore-forming systems. We present molybdenum isotope data from 12 hydrothermal syndepositional silicalite and carbonaceous slate samples from the Dajiangping pyrite deposit in western Guangdong Province, South China. The δ ^97/95 Mo values from Orebody III range from −0.02‰ to 0.29‰, with an average of 0.18‰. In contrast, the composition values from Orebody IV display a larger variation from −0.70‰ to 0.62‰. However, the five samples from the main ore bed all show strong negative values. This indicates that the significant variation in molybdenum isotopic composition supports different hydrothermal ore-forming metallogenesis and a metallogenic environment between the two orebodies. Orebody III is likely to have been deposited from submarine exhalative hydrothermal fluids under a relatively strong reducing environment and Orebody IV may have also been influenced by hydrothermal superimposition in a more oxidized disequilibrium condition. In addition, the δ ^97/95 Mo values of Orebody IV are clearly negative, together with the values increasing stratigraphically upward in the ore beds, suggesting that the metallogenic environment of Orebody IV is different from the open oceanic systems. There might be dynamic fractionation in this restricted environment. Therefore, the molybdenum isotope can be used as an effective tracer for the ore-forming fluid and metallogenic environment.     

火星生命的形成和消失

早期火星的气候是否与早期地球的气候相似 ,过去有过许多理论解释地球生命的起源 ,因此科学家更加关注火星上可能曾有过生命这一设想     

存货影响销售率的短生命周期物品库存管理

电子元件、计算机、彩电、空调等产品的生命周期正变得越来越短,在确定经济定货批量时,这些物品因为物理变质率太小而不需要去考虑物理变质的影响,但是在存储过程中随着时间的推移这类物品的价值会发生贬值,称之为无形变质。假设需求率受到存货水平的影响、无形变质率与需求率负相关,即需求率大时无形变质率较小,反之亦然,建立了短生命周期物品的库存模型,证明了最优解的存在性和惟一性。举数字实例进行了验证,并对各参数进行了敏感性分析。     

东昆仑地区石墨矿地质特征及找矿前景初探

通过对青海省格尔木市郭勒木德镇晶质石墨矿含矿特征、岩石地球化学特征以及成矿环境的分析,查明晶质石墨矿赋存于早元古代金水口岩群白沙河岩组的大理岩段与加里东期岩浆接触部位;大理岩具有构造多期叠加、变形强烈的特征.晶质石墨矿具有层控后期热液变质的特征,具有很好的成矿环境和找矿前景.