湖南花垣地区礁灰岩型铅锌矿成矿特征及找矿方向     

任爱君  毛党龙  陈伦杰 《国土资源导刊(湖南)》2017,14(1)

在花—张断裂带两侧分布着众多铅锌矿床,这些矿床赋存于寒武系下统的海相礁灰岩中,受岩性和断裂控矿明显,以层状、似层状为主,成矿流体为高盐度热卤水的沉积岩型铅锌矿床,有着特殊的成矿背景及成矿条件,与MVT相似、但有不同特征的铅锌矿床,称之为"礁灰岩型"铅锌矿床。通过阐述近年发现的"礁灰岩型"铅锌矿床的成矿特征,圈定该类矿床的找矿潜力地段,以期为找到更多的礁灰岩型铅锌矿床提供参考。  相似文献   

柿竹园矿床S同位素地球化学研究     

王谦  莫南  毛彦东 《国土资源导刊(湖南)》2017,14(2)

通过硫同位素低温平衡系统,分析平衡条件下δ~(34)S_(H_2S)与δ34S热液偏差,获得成矿流体的含硫组分以H_2S为主。成矿阶段δ~(34_S值变化范围狭窄,呈塔式分布,具有岩浆硫特征,柿竹园矿床矿石中的硫来自岩浆流体,即千里山花岗岩。硫同位素fO_2—pH值关系图,投影得出350℃时,fO_2为-28.3~-31.5;250℃时,fO_2为-35.4~-37.5。  相似文献   

Analyzing land-use change in farming-pastoral transitional region using autologistic model and household survey approach     

Likai Zhu  Jijun Meng  Xiyan Mao 《中国地理科学(英文版)》2013,23(6):716-728

Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic model, and household survey method, this study investigated major land use changes and their causes from 1978 to 2008 in Uxin Banner （county-level）, Inner Mongolia in China and then developed an understanding of the relationships between household livelihood and land-use pattern. Results showed that cultivated land increased from 1988 to 2000, and leveled offafter 2000. Built-up land increased stably for the period 1978 2008. The change of grassland and bare land differed among the three periods. From 1978 to 1988, grassland increased by 23.3%, and bare land decreased by 20.48%. From 1988 to 2000, bare land expanded by 1.7%, but grassland declined by 1.3%. From 2000 to 2008, an increase in grassland area by 1.8% was observed, but a decrease in bare land area by 9.0% was witnessed. The autologistic models performed better than logistic models as indicated by lower Akaike Information Criterion （AIC） values. Factors associated with human activities significantly correlated with the change of cultivated land, forest land, grassland, and built-up land. The produce prices and extensive cultivated land use are major issues in the farming area. This study suggests that completing land circulation systems and maintaining the stability of price are effective solutions. By contrast, reclamation and overgrazing are major concerns in the pastoral areas. Implementing environmental policies effectively, transferring population out of rural pastoral areas, and developing modem animal husbandry are effective ways to address these issues.  相似文献   

形变仪器影响观测质量因素   总被引：3，自引：2，他引：1  

卢双苓  于庆民  郝军丽  赵小贺  王帅合  毛玉华 《地震地磁观测与研究》2012,33(5):261-266

通过对泰安地震台形变仪器观测资料质量的统计分析,发现影响观测质量的主要因素包括：观测环境的改善、优化可以提高观测精度;仪器管理和数据处理水平可以影响数据精度;降雨、吸潮等可以对曲线趋势变化造成影响;环境恶化,如外界抽水等干扰,会使曲线日变固体潮失真,从而掩盖真实的地壳信息。  相似文献   

Evolving a core-periphery pattern of manufacturing industries across Chinese provinces   总被引：1，自引：0，他引：1  

Qiliang Mao  Fei Wang  Jun Li  Suocheng Dong 《地理学报(英文版)》2014,24(5):924-942

This paper, concerning uneven development in China, empirically analyzes the core-periphery gradient of manufacturing industries across provinces （autonomous regions, municipalities）, and assesses the extent to which these provinces have changed in recent years. Since China＇s reform and opening-up, the spatial structure of the economy has pre- sented a significant core-periphery pattern, the core evidently skewing towards east-coastal areas. With the deepening of market reforms and expansion of globalization, industrial loca- tion is gradually in line with the development advantages of provinces. The core provinces specialize in those industries characterized by strong forward and backward linkages, as well as a high consumption ratio, a high degree of increasing returns to scale, and labor or hu- man-capital intensity. However, it is the opposite with regard to peripheral provinces, in addi- tion, energy intensive industries are gradually concentrating in these areas. To a certain de- gree, the comparative advantage theory and new economic geography identify the underlying forces that determine the spatial distribution of manufacturing industries in China. This paper indicates that the industrialization of regions along different gradients becomes unsynchro- nized will be a long-term trend. Within a certain period, regions are bound to develop indus- trial sectors in line with their respective characteristics and development stage. A core-periphery pattern of industries also indicates that industrial development differentials across regions arise because of not only the uneven distribution of industries but also the inconsistent evolving trends of industrial structure for each province.  相似文献   

荒漠草地植物多样性对肥料添加的响应     

涂文霞  叶茂  徐海量  赵新风 《中国沙漠》2013,33(5):1349-1355

选择古尔班通古特沙漠南缘典型丘间低地荒漠草地,采用完全随机区组设计,通过设置8个肥料添加处理（CK、N、P、K、NP、NK、PK、NPK）,研究了荒漠草地植物多样性对不同肥料添加处理的响应,得出以下结论:（1）研究区植被丰富度指数在P、NP、PK肥添加的作用下显著增加,而其余处理对其影响不显著, NK处理使研究区植被丰富度指数下降;多度指数在不同肥料添加下表现出与丰富度指数相同的特征;（2）不同施肥处理对荒漠草地的生物多样性有不同程度的影响:P肥、NP肥的添加使Simpson指数、Shannon-Weiner指数和Pielou指数与对照（CK）相比显著增加（p＜0.05）,表明P肥添加、NP肥添加是增加新疆荒漠草地生物多样性的有效措施;（3）植被丰富度指数在年际间的变化表现为:2009年开始施肥,2010年丰富度指数下降,2012年丰富度指数上升,即随着施肥时间的推移,同一块样地丰富度指数呈先下降后增加的趋势,均匀度指数随时间呈上升趋势。  相似文献   

老挝万象省爬立山（PHaLek）铁矿床地质特征及成矿作用分析   总被引：3，自引：0，他引：3  

朱华平  范文玉  毛洪江  吴振波  高建华  刘书生 《吉林大学学报(地球科学版)》2014,44(5):1492-1501

爬立山铁矿床位于长山褶皱带北西端,是长山成矿带内与岩浆作用有关的一个大型铁矿床。根据野外地质观察及室内对含矿岩体、赋矿围岩和矿石开展的岩相学和地球化学研究发现：与成矿作用有关的花岗质岩石属钙碱系列准铝质的I型花岗岩,成岩的构造环境为火山弧。矿区内发育致密块状磁铁矿、孔洞状赤铁矿、砂砾土状铁矿等3种铁矿石。结合岩（矿）石微量元素分析,认为爬立山铁矿具有复合成矿作用特征,主要可分为3个成矿阶段：早期以与华力西期岩浆侵入作用有关的接触交代成矿作用为主,形成矽卡岩型磁铁矿;其后,在褶皱造山后形成的断陷盆地中,由于火山喷发（溢）作用形成孔洞状熔岩型赤铁矿;最后随着新生代地壳抬升,发生表生物理化学风化成矿作用,形成如今的砂砾土状型铁矿。  相似文献   

Seismic inversion with generalized Radon transform based on local second-order approximation of scattered field in acoustic media          下载免费PDF全文

Wei Ouyang  Weijian Mao  Xuelei Li  Wuqun Li 《地震科学（英文版）》2014,27(4):433-439

Sound velocity inversion problem based on scattering theory is formulated in terms of a nonlinear integral equation associated with scattered field. Because of its nonlinearity, in practice, linearization algorisms (Born/single scattering approximation) are widely used to obtain an approximate inversion solution. However, the linearized strategy is not congruent with seismic wave propagation mechanics in strong perturbation (heterogeneous) medium. In order to partially dispense with the weak perturbation assumption of the Born approximation, we present a new approach from the following two steps: firstly, to handle the forward scattering by taking into account the second-order Born approximation, which is related to generalized Radon transform (GRT) about quadratic scattering potential; then to derive a nonlinear quadratic inversion formula by resorting to inverse GRT. In our formulation, there is a significant quadratic term regarding scattering potential, and it can provide an amplitude correction for inversion results beyond standard linear inversion. The numerical experiments demonstrate that the linear single scattering inversion is only good in amplitude for relative velocity perturbation ( \( \delta_{c}/c_{0} \) ) of background media up to 10 %, and its inversion errors are unacceptable for the perturbation beyond 10 %. In contrast, the quadratic inversion can give more accurate amplitude-preserved recovery for the perturbation up to 40 %. Our inversion scheme is able to manage double scattering effects by estimating a transmission factor from an integral over a small area, and therefore, only a small portion of computational time is added to the original linear migration/inversion process.  相似文献   

准噶尔盆地隆起区石炭系顶面不整合及其意义及其意义          下载免费PDF全文

毛翔  李江海  张华添  李维波  王洛 《古地理学报》2014,16(4):527-536

石炭系风化壳是准噶尔盆地火山岩油气储集层的主要类型,物性明显好于同时代原生型火山岩。通过对陆梁隆起滴西地区的铸体薄片与岩心观测,发现风化淋滤对火山岩储集性能的改造主要体现在孔隙上,对裂缝的改造作用不明显。由于火山岩形成的构造环境与古地貌存在差异,不同的海拔高度决定了其接受风化时间的长短。准噶尔盆地内石炭系不整合上覆地层时代存在明显差异,下二叠统至白垩系均有分布。最长风化时长在东部隆起约为150Ma,在陆梁隆起约为100Ma,在西部隆起约为55Ma;而3处隆起最少则仅缺失部分上石炭统-下二叠统。风化时长的长短与火山岩孔隙度的大小呈近波峰状对应关系,火山岩孔隙度初始随风化时长的增大(至约30Ma)逐渐增大,在到达峰值(对应风化时长约40Ma)后随时长的增大(55～100Ma)逐渐减小。最大的孔隙度均出现在火山角砾岩和玄武岩中,安山岩的孔隙度次之,而凝灰岩的孔隙度最小。  相似文献   

Why Hydraulic Tomography Works?     

Tian‐Chyi J. Yeh  Deqiang Mao  Yuanyuan Zha  Kuo‐Chin Hsu  Cheng‐Haw Lee  Jet‐Chau Wen  Wenxi Lu  Jinzhong Yang 《Ground water》2014,52(2):168-172

  相似文献