Mesozoic molybdenum deposits in the east Qinling–Dabie orogenic belt: Characteristics and tectonic settings

The East Qinling–Dabie orogenic belt accommodates the largest Mo ore district in the world. It contains 8.43 Mt of proven Mo metal reserves which accounts for 66% of the total proven Chinese Mo reserves. The Mo ore district includes 24 deposits and 12 occurrences, with four major types of Mo mineral systems, i.e., porphyry, porphyry-skarn, skarn and hydrothermal veins. The latter can be further subdivided into quartz vein and carbonatite vein types. Although Mo mineralization in the belt began in the Paleoproterozoic (1680 ± 24 to 2044 ± 14 Ma), all economically significant deposits were formed during the Mesozoic. Re/Os dating of molybdenite has shown that there are three episodes of Mo mineralization, i.e., Late Triassic (233–221 Ma), Late Jurassic to Early Cretaceous (148–138 Ma) and Early to middle Cretaceous (131–112 Ma).Late Triassic Mo deposits developed as molybdenite–quartz veins and carbonatite vein types. Stable isotope systematics (C, O, S) and high contents of Re and Sr indicate that the carbonatite Mo veins are mantle-derived. Porphyry and porphyry–skarn Mo mineral deposits were formed in the Late Jurassic to Early Cretaceous and Early to middle Cretaceous. The Late Jurassic to Early Cretaceous granite porphyries that are associated with the Mo deposits usually occupy less than 1.5 km² at the surface and are situated in the East Qinling area, far west of China's continental margin. On the other hand, the Early to middle Cretaceous batholiths and granite porphyries, , with associated Mo deposits are located in the Dabieshan area and eastern part of the East Qinling area. The Late Jurassic to Early Creataceous granitoids and related Mo deposits possibly formed in a back-arc extensional setting of the Eurasian continental margin, which was probably triggered by the oblique subduction of the Izanagi plate. The Early to middle Cretaceous batholiths and granite porphyries are linked to the tectonic regime of lithospheric thinning, asthenospheric upwelling and partial melting of the crust, induced by a change in Izanagi Plate motion parallel to the continent margin.In the East Qinling–Dabie belt there are vein type Pb–Zn–Ag deposits surrounding porphyry and/or porphyry–skarn Mo (W) deposits, forming well defined ore clusters. The same spatial arrangement (i.e., porphyry Mo stockworks and outlying Pb–Zn–Ag ore veins) is also observed at the deposit scale. Thus, Mo porphyry stockworks and distal polymetallic veins belong to the same ore system and may reflect an outward temperature decrease from the highly fractionated granite plutons. Both, porphyry stockworks and polymetallic veins, can be used as vectors for further prospecting.     

Last glacial pollen record from Lanzhou (Northwestern China) and possible forcing mechanisms for the MIS 3 climate change in Middle to East Asia

The vegetation on the northeastern margin of the Tibetan Plateau is highly sensitive to climatic changes and thus represents a potentially interesting environmental archive. Pollen samples from the Fanjiaping Loess section in Lanzhou on the western Chinese Loess Plateau (CLP) were analyzed in conjunction with OSL dating. The results indicate that pollen zone B (60.6–46.0 ka, correlative to the early MIS 3) had the greatest abundances of Cupressaceae, Tsuga, Gramineae and Cyperaceae of the entire section, suggesting a warm phase during the last glacial period. These pollen taxa decreased significantly in abundance in the zones C (46.0–39.0 ka) and D (39.0–27.0 ka), reflecting a substantial climate cooling from the middle MIS 3 to MIS 2. These results correlate with climate records from the South China Sea, the CLP, Baikal Lake, North America, North Atlantic Ocean and other regions, and probably correspond with the decline of northern high-latitude insolation and the increase of global ice volume from 50 to 20 ka. In particular, arboreal pollen, fern spore and algae abundances declined sharply since ～40 ka, while shrub and herb pollen reached the highest abundances. Conifer pollen Picea and Abies abundance also rose markedly and increased up the section. This implies significant climate deterioration and likely corresponded with substantial growth of the polar ice sheets since ～40 ka. The decreasing temperature caused by an insolation decline during the last glacial period probably reinforced the cooling effect in a ‘snow/ice/albedo’ feedback, which would result in less climate sensitivity to radiative forcing. Meanwhile, vegetation decline in the Northern Hemisphere during the last glacial period and tundra development at high latitudes possibly caused additional cooling, enhancing the growth of polar ice sheets since 40 ka. The development of polar ice sheets increased the polar-to-equator temperature and pressure gradients, strengthening the westerlies and supplying plenty of moisture to Northwest China during 40–30 ka. Lake sediments developed widely on the Tibetan Plateau during 40–30 ka, probably related to an increase in the seasonality of middle-to-low latitude insolation which caused an enhancement of glacier melting on the Plateau.     

上海城市废弃物增长的环境库兹涅茨特征研究

对上海1978～2000年人均GDP与城市废弃物增长数据的拟合计算表明,上海城区废弃物增长与人均GDP之间存在比较明显的环境库兹涅茨二次曲线特征。理论计算显示:上海城市废弃物环境库兹涅茨曲线的转折点为人均GDP约33441元,对应的城市废弃物达到相应的理论计算峰值约779万吨。上海的人均GDP在2000年已经达到34547元,相应的城市废弃物清运量为741万吨,略为低于理论拟合计算峰值;说明上海城市废弃物增长的演变在2000年前后的一段时期,总体已经处于环境库兹涅茨曲线的理论峰值转折点附近。可以认为,随着上海人均GDP的持续增长,今后一段时期内上海城市废弃物的总量增长会逐步减缓,而建立体现生产者责任的市场调控废弃物管理公共政策,将有利于加快这一趋势。     

电气石对成岩成矿环境的示踪性及应用条件

本文在系统查阅国内外文献的基础上，结合对我国部分地区电气石的研究，讨论了电气石在不同成岩成矿环境中的鉴别特征及应用条件。在以火山岩和以沉积岩为含矿岩石的块状硫化物矿床中，电气石通常为富镁的镁电气石－黑电气石固溶体系列。在花岗岩、伟晶岩和细晶岩中，电气石有镁电气石－黑电气石固溶体系列→黑电气石－锂电气石固溶体系列→锂电气石和镁电气石－黑电气石固溶体系列→黑电气石电两个方向。此外，还提出了应用电气石指     

江山-绍兴断裂带在杭州湾延伸的探讨

江山-绍兴断裂带斜贯浙江境内,是我国东部一条重要的大地构造分区界线。在浙江陆区部分,江山-绍兴断裂带基本上顺浙赣铁路方向,从江山沿金衢盆地南缘,经乌灶至绍兴平水、富盛。过绍兴后,江山-绍兴断裂带是否继续向杭州湾海域延伸以及如何延伸,则认识分歧。     

塔里木河源流区气候变化和年径流量关系初探

基于1957~2003年塔里木河流域源流区长期监测资料,分析塔里木河流域源流区的主要河流年径流量和相应气温、降水变化的特点,探讨流域内气候变化与水资源量变化的关系。利用非参数检验的方法,分析温度、降水变化与径流量变化的关联性和一致性。结果显示:在塔里木河流域源流区,温度在0.05水平上呈现单调递增的趋势,降水则表现为不显著增加的走势,而径流量基本均出现了递增现象;从参数检验和非参数分析的结果看,温度升高与径流量增加的关联趋势更明显。     

Tailed Radio Sources in the CDFS Field

Using 1.4 GHz ATCA & VLA images with 5.5 GHz ATCA data, we present a sample of 12 bent-tailed galaxies over the 4 deg² area of the Chandra Deep Field South (CDFS). We find 10 new sources, one of which is possibly the highest red-shift bent-tailed galaxy detected at z ∼ 2.     

基于项目式学习的红色文化研学旅行课程设计--以“天山脚下的纪念”为例

青少年红色文化研学旅行把爱国主义、红色传统和红色精神传播到青少年之中,具有特殊的意义。引导青少年坚定理想信念,为实现中华民族伟大复兴的中国梦努力奋斗,是红色研学旅行的重要任务。本文采用PBL模型,依托伊犁有关林则徐的历史文化资源,设计了以“天山脚下的纪念”为主题的高中学段研学旅行实践活动;引导学生通过了解林则徐传奇的一生,懂得继承和弘扬林则徐艰苦奋斗、爱国爱乡的情怀;最后对基于PBL模型的“天山脚下的纪念”研学旅行课程进行了反思。     

考虑海水强跃层特征的MVP系统盐度剖面校正方法试验

走航式海洋剖面测量系统（Moving Vessel Profiler,MVP）具有空间高分辨率温盐剖面探测的优势,但由于采用无泵型CTD进行温盐测量,对测量数据进行传感器响应时间匹配和热惯量校正处理是其数据应用的重点和难点。本文针对现有热惯量校正方法在强温跃层处仍然存在盐度尖峰的局限性,提出一种基于测量温度梯度廓线分析的分层热惯量校正参数寻优方法,校正温度和电导率,进而校正盐度剖面。利用西太平洋某航次实测数据进行试验,结果表明,该方法显著降低了MVP上下行测量剖面的盐度差异,盐度尖峰基本被剔除,特别是温跃层处得到明显改善,上下行剖面的平均绝对盐度差从0.031降低到0.016 1,总体的盐度误差减小48.1%,验证了本文提出的MVP盐度剖面校正方法的合理性。     

云南气候对人类住宅行为的影响

本文论述了云南省气候特点及其与云南各种住宅类型之间的关系,分析了气候环境对人类住宅行为的控制作用,并指出了气候影响与其他自然因素及文化传统影响之间的联系。