Skarn-type tungsten mineralization associated with the Caledonian (Silurian) Niutangjie granite,northern Guangxi,China

The Niutangjie tungsten deposit is a bedded skarn-type scheelite deposit and is located at the junction between Ziyuan and Xingan counties in the north of Guangxi,China.The deposit is genetically related to a fine-grained two-mica granite within the orefield.Zircon LA-ICP-MS U-Pb dating of the granite yielded a Silurian(Caledonian)age of 421.8±2.4 Ma,which is contemporaneous with the adjacent Yuechengling batholith.Mineralization within the skarn is associated with a quartz,garnet,and diopside gangue,and scheelite is present in a number of different mineral assemblages,such as quartz-scheelite and quartz-sulfide-scheelite;these assemblages correspond to oxide and sulfide stages of mineralization.Sm-Nd isotope analysis of scheelite yielded an isochron age of 421±24 Ma.Although the uncertainty on this date is high,this age suggests that the scheelite mineralization formed during the Late Caledonian,at a similar time to the emplacement of the Niutangjie granite.Zircons within the granite have?Hf(t)values and Hf two-stage model ages of?6.5 to?11.6,and 1.79 to 2.11 Ga,respectively.These data suggest that the magma that formed the granite was derived from Mesoproterozoic crustal materials.Scheelite?Nd(t)values range from?13.06 to?13.26,also indicative of derivation from ancient crustal materials.Recent research has identified Caledonian magmatism in the western Nanling Range,indicating that this magmatism may be the source of contemporaneous tungsten mineralization.     

Land cover mapping using time series HJ-1/CCD data

It is very difficult to have remote sensing data with both high spatial resolution and high temporal frequency; thus, two categories of land-use mapping methodology have been developed separately for coarser resolution and finer resolution data. The first category uses time series of data to retrieve the variation of land surface for classification, which are usually used for coarser resolution data with high temporal frequency. The second category uses fine spatial resolution data to classify different land surface. With the launch of Chinese satellite constellation HJ-1in 2008, four 30 m spatial resolution CCDs with about 360 km coverage for each one onboard two satellites made a revisit period of two days, which brought a new type of data with both high spatial resolution and high temporal frequency. Therefore, by taking the spatiotemporal advantage of HJ-1/CCD data we propose a new method for finer resolution land cover mapping using the time series HJ-1/CCD data, which can greatly improve the land cover mapping accuracy. In our two study areas, the very high resolution remote sensing data within Google Earth are used to validate the land cover mapping results, which shows a very high mapping accuracy of 95.76% and 83.78% and a high Kappa coefficient of 0.9423 and 0.8165 in the Dahuofang area of Liaoning Province and the Heiquan area of Gansu Province respectively.     

Petrogenesis and tectonic implications of Late-Triassic high εNd(t)-εHf(t) granites in the Ailaoshan tectonic zone(SW China)

High εNd(t)-εHf(t) granites are robust evidence for crustal growth. In this paper we report results of petrologic, geochronological and geochemical investigations on the Huashiban granites from the Ailaoshan tectonic zone in western Yunnan(SW China). Zircon grains separated from the two samples(10HH-119 A and 10HH-120A) yield the weighted mean 206Pb/238 U ages of 229.9 ± 2.0 Ma and 229.3 ± 2.3 Ma, respectively, interpreted as the crystallization ages of the granites. Based on our results, in combination with the existing U-Pb geochronological data for the Ailaoshan metamorphic rocks, we propose that the Ailaoshan Group might be a rock complex composed of the Mesoproterozoic, Neoproterozoic, Hercynian, Indosinian and Himalayan components, rather than a part of the crystalline basement of the Yangtze block. The zircon grains show highly depleted Lu-Hf isotope compositions, with positive εHf(t) values ranging from 8.4 to 13.1. The Huashiban granites have high SiO2(72.66 wt%–73.70 wt%), low Mg#(0.28–0.34) with A/CNK=1.01–1.05, and can be classified as peralumious high-K calc-alkaline I-type granites. A synthesis of these data indicates that the Ailaoshan tectonic zone had evolved into a post-collisional setting by the Late-Triassic(229 Ma). Genesis of the Huashiban high εNd(t)-εHf(t) granites involved into two processes:(1) underplating of the sub-arc mantle into the lower crust, and(2) remelting of the juvenile crustal materials in response to the upwelling of the asthenospheric mantle in the post-collisional setting.     

深部地应力探测技术理论探讨

地应力测量的研究已有几十年的历史,但是对于地下深部地应力非钻孔式测量探测技术的发展,则一直进展很慢。本文依据天然电磁波场源,利用光弹实验模型原理,研制了ＤＹＬ型地应力探测仪,并在淮南地区地庆力状态普查过程中,取得了明显的应用效果。     

南黄海地震区的地震活动性研究

北纬３１°—３５°、东经１１９°—１２５°范围内的南黄海地震区,中强地震活动频繁,这主要是由一组北北东向和北西—北西西向共轭走滑活动断层及张性铲形活动断层引起的,该区内的中强震活动具有准周期性,震中呈东移趋势,区内地震在原地或同一构造部位重复发生的概率比较高,且空间分布是不均匀的,其中,海域地震强度明显高于陆域地震,在第Ⅲ、Ⅳ地震活跃期内,中强震主要发生在北纬３３°±１°、东经１２１°±１°所在的南黄海海域的南部盆地,本区第Ⅳ活跃期内中强地震的活动水平与近期内中小地震的活动水平相当,同时,海域地震还具有成丛性及５７ 年、６ 年的节律,地震震中具有南北迁移的特征     

我国近年水库地震监测综述

在较完整地收集我国水库诱发地震震例的基础上,回顾了我国水库诱发地震监测的成长进步厍程。本文认为无线遥测组网和计算机实时处理方式是我国近年水库诱发地震监测的主流,数字化则是其发展方向。作者提出了按地震监测系统的主要特征。对水库地震监测台网分类划代方法,将我国已客在建的水库地震监测台网划分四代。本文较详细地介绍了近年建成投测的二滩,大桥、小浪底和李家峡等第三代水库遥测地震台网的基本情况。对正在设计建设     

7 诱发地震

诱发地震为第六专题,共征集论文9篇,数量较少.然而,诱发地震研究,尤其是水库诱发地震研究是大会主持单位印度国家地球物理研究所(NGRI)的强项,所以倍受大会重视.大会主席NGRI的所长H.K.Gupta在开幕式后的特邀报告中,花了近一半时间讲述了世界闻名的印度柯依纳水库诱发地震的30年研究历史和近期的研究成果.     

Accumulation characteristics and the main controlling factors of Lunnan multilayer oil province,Tarim Basin,China

Lunnan region is a large-scale paleohigh with many coexisting oil and gas bearing series. At present, about 2 billions tons of proved, probable and possible oil and gas reverses have been proved there. Eight oil and gas bearing series have been found in the Ordovician, Carboniferous, Triassic and Jurassic of Lunnan region, they all bear the characteristics of large-scale multilayer oil-gas province. Ordovician is the main reservoir series where over 0.8 billion tons of oil geologic reserves were discovered, and a super large-scale marine carbonate oil and gas field has formed. Reservoir space of the carbonate reservoirs is mainly composed of dissolved hole, dissolved pore and fracture in Lunnan paleo-burial hill. Generally, dissolved holes are widely distributed among them. Reservoir developments are mainly controlled by karstification and tectonic disruption. Due to the similar geochemical characters, the Ordovician, Carboniferous, Triassic and Jurassic oil and gas reservoirs present the same oil source rock of Mid-Upper Ordovician, the latter except Ordovician are mostly of secondary oil and gas reservoirs migrated vertically by faults during the process of multiple phase tectonic movement, adjustment and reconstruction. Lunnan composite oil and gas accumulation region is situated in the vicinity of large-scale hydrocarbon generation depressions in three directions, ample oil and gas from hydrocarbon generation depressions supplied the adjacent oil and gas reservoirs once. Hereby, the succeed paleohigh is the long-term hydrocarbon accumulation region, which is favor for the formations of high quality reservors, fault systems and huge-scale composite oil and gas accumulation.     

地震快速数据发布系统

利用成熟的、性能优异的GMT和SAC作为后台处理软件，并辅以MySQL数据库系统来管理数据。实现了地震快速数据的自动、及时发布。