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71.
论胶西北河西金矿床成因及其动力学条件 总被引:6,自引:0,他引:6
胶东河西金矿床属于典型的蚀变岩型金矿床.金矿体赋存于玲珑黑云母花岗岩体内,并受北东向断裂构造带所控制.87Sr/86Sr的初始比值表明,玲珑黑云母花岗岩和郭家岭花岗闪长岩均为壳源深熔花岗岩.地质和同位素年代学资料表明,金成矿作用发生在早白垩世.据硫、氧同位素组成判断,河西金矿床的成矿作用可能与郭家岭花岗闪长岩的流体活动有关,其成矿温度以中温为主,成矿压力为(1*!200~1*!400)×105 Pa.河西金矿床的花岗岩、蚀变岩和矿石的稀土与微量元素分布模式明显相似,说明它们有着共同的成因,与壳熔花岗岩岩浆作用有关. 相似文献
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平和铜钟坑一带1:10000土壤测量圈定了锡、钼、铜、铅、锌等元素异常及5个锡矿化蚀变带。铜钟坑锡异常分布于晚侏罗世南园组第二段火山碎屑岩中,异常范围大,浓度较高。裂隙带发育,矿化贮存于裂隙带中,成矿条件好。 相似文献
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九寨沟7.0级地震诱发的地质灾害具有高位滑坡远程灾害的特点,传统地质灾害排查手段无法有效解决隐患的早期识别问题。本文采用机载激光雷达测量技术,快速获取九寨沟地震核心景区的激光点云数据。通过构建高精度数字高程模型(DEM)、数字正射影像图(DOM),建立三维地质灾害解译场景,利用数字地形分析、地形形态学分析和计算机图像识别等技术,综合开展九寨沟高位远程区域内隐蔽性强、随机性大的地质灾害隐患早期识别与分析。应用实践表明,机载激光雷达测量技术可以提高九寨沟地震灾区地质灾害隐患的早期识别能力,对进一步提高综合防灾减灾能力提供了一些可借鉴的思路。 相似文献
76.
徐勇航 王亮 赖志坤 徐晓辉 王凤 刘升发 石学法 TROA Rainer Arief ZURAIDA Rin TRIARSO Eko HENDRIZAN Marfasran 《海洋学报(英文版)》2019,38(1):78-84
通过对东印度洋钻孔CJ01-185的生物硅来探讨东印度洋古生产力的变化和古气候演化的响应。CJ01-185钻孔的生物硅含量在末次冰期最低,为0.86%;而到了全新世晚期生物硅含量达到1.89%。全新世晚期生物硅的堆积速率明显大于末次冰期。随着全新世海平面的快速上升,巽他海峡贯通,来自爪哇海的陆源物质输入到东印度洋,导致全新世的生物硅含量和生物硅的堆积速率增加。研究表明:巽他海峡贯通前,研究区的古生产力主要受东南季风变化和上升流的活动影响;而巽他海峡贯通后,古生产力很明显受到陆源物质输入的控制,东南季风变化和上升流的影响较弱。 相似文献
77.
Jiangfeng She Xinchi Li Yaqian Chen Junzhong Tan 《International journal of geographical information science》2019,33(10):2033-2054
Adding building labels greatly improves the recognizability of buildings and the readability of three-dimensional (3D) city scenes. However, building label placement is much more complex in 3D scenes than in two-dimensional (2D) maps. The annotation effect is influenced by the attributes of the 3D label, building visibility, and the spatial relationship between the building and viewpoint. In this context, automatically generating building labels for 3D scenes during interactions requires highly complex computations. By contrast, evaluating candidate labels and then selecting the suitable label for each building can be effectively implemented. This paper introduces an approach for labeling buildings in 3D scenes based on evaluations of label candidates. The proposed method predefines a candidate label set for each building. These candidates are then evaluated in terms of their attributes and the relationship between the labels and viewpoint at runtime. The best candidate label, or a situational alternative for each building, is then placed in order of comprehensive label priority to avoid annotation conflicts. A series of experiments demonstrate that this method effectively enhances the correlation of labels and buildings, improves interactive efficiency, and realizes a viable global label layout. 相似文献
78.
Dengyun Wu Zhikun Ren Lü Honghua Jinrui Liu Guanghao Ha Chi Zhang Menghao Zhu 《地球科学进展》2020,35(4):389-403
Alluvial fans can preserve historical records of sediment transport to middle and lower river systems or piedmont basins, which are considered to be sensitive recorders of climate change and tectonic activity. In this paper, the morphological characteristics, control factors and future development trend of alluvial fan are summarized and described. The main understanding is as follows: According to the gravity flow and traction flow process, fan can be divided into debris flow alluvial fan and fluvial fan. The former is formed under the action of debris gravity flow deposits, which is related to the occasional flood and burst flow in a short time. The latter is braided tributaries depositions which are gradually shallower and spread radially in the direction of fan toe under the traction water transport. The erodibility of underlying bedrock can affect the scale of downstream alluvial fan, which depends on the sediment production and store factors in the catchment. The easily eroded bedrock may produce more sediment, making the alluvial fan area larger. In the contrast, the erodibility of rocks in the source area can also affect the slope and hydrological characteristics of the valley so that more sediment is deposited in the upstream basin and the alluvial fan formed in the downstream is smaller. Tectonic activity is the pre-condition for the development of alluvial fans, which provides a space for alluvial fans depositions. Faulting in the piedmont can change the position and morphology of the ancient alluvial fan, and also cause deformation or distortion of the thick sedimentary sequence to record the regional tectonic activity. The quaternary alluvial fan sequence corresponds well to the climate change during the glacial-interglacial period. However, the influence of the flood events caused by extreme meteorological events on alluvial fan deposition should be focused on. The application of a series of new techniques and methods will help to carry out deep research on alluvial fan in the future, such as high-resolution observation technique, physical simulation experiment, and precise dating. 相似文献
79.
光泽县测家山-罗家坑一带萤石矿位于闽西北萤石成矿带内的光泽司前-李坊萤石矿成矿远景区内,分布有罗家坑、测家山萤石矿,以及富家坪、早洲、测家山南萤石矿点和早洲东萤石矿(化)点;本文通过综合分析研究区地质背景,分析萤石矿的矿区、矿体地质特征,结合研究区地球物理、地球化学成果,认为区内萤石矿为沿断裂充填的中低温热液充填型萤石矿床,萤石矿主要分布于晚侏罗世花岗岩内的北东、北北东向,次为近南北向断裂构造中。该区具有很好的形成中低温热液充填型萤石矿床的条件,具有形成中大型萤石矿床的潜力。 相似文献
80.