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991.
USING STEREO-PAIR AND DIFFERENTIAL GPS TO REVEAL SURFACE DEFORMATION CHARACTERISTICS OF THE MINLE-YONGCHANG FAULT 下载免费PDF全文
ZOU Xiao-bo YUAN Dao-yang SHAO Yan-xiu LIU Xing-wang ZHANG Bo YANG Hai-bo 《地震地质》2017,39(6):1198-1212
Qilian Shan-Hexi Corridor is located in the northeastern margin of the Tibetan plateau, which hosts many active strike-slip and thrust faults as well as folds. Previous study on this area was mostly concerned with large faults at the boundary of the corridor, while rare work on active tectonics in the interior of the corridor. On 25 October 2003, the Minle-Shandan MS6.1 earthquake occurred in this area, which is related with the Minle-Yongchang fault hidden beneath the south piedmont of the Dahuangshan Mountains. As there is no obvious rupture trace on the surface, the quantitative study of this fault has never been reported so far.
In order to obtain quantitative parameters of this active structure efficiently, the software of ERDAS was used to generate pointscloud data from SPOT6 stereo-pair. Two-meter resolution DEM imagery from point cloud has the line accuracy of height about 1m. Three swath profiles were extracted from the DEM data, which show that high geomorphic surfaces are all uplifted and folded. By differential GPS measurement, the vertical uplift of the thrust-related fold is estimated to be about 2.0m on the T2, and the strike of the fold deformation is nearly 311°, which is close to the result of the fault parameter determined by aftershocks, and also in agreement with the focal mechanism solutions. Furthermore, the location of fold axial zone is consistent with the actual investigation data. These indicate that there is obvious tectonic deformation in the west part of the Minle-Yongchang fault. It supports the view that this fault is the seismogenic structure of the 2003 Minle-Shandan earthquake. Stereo-pair is of high importance in active tectonics research, which can provide significant guidance for field geologic investigations and determining the location of tectonic deformation, according to this research. 相似文献
992.
ZHANG Xiaoxu TANG Juxing LIN Bin WANG Qin HE Liang YAN Gang SHAO Rui WU Qiang DU Qiu ZHAXI Pingcuo 《《地质学报》英文版》2024,98(3):701-716
Multistage tungsten mineralization was recently discovered in the Mamupu copper-polymetallic deposit in the southern Yulong porphyry copper belt (YPCB), Tibet. This study reports the results of cathodoluminescence, trace element and Sr isotope analyses of Mamupu scheelite samples, undertaken in order to better constrain the mechanism of W mineralization and the sources of the ore-forming fluids. Three different types of scheelite are identified in the Mamupu deposit: scheelite A (Sch A) mainly occurs in breccias during the prograde stage, scheelite B (Sch B) forms in the chlorite-epidote alteration zone in the retrograde stage, while scheelite C (Sch C) occurs in distal quartz sulfide veins. The extremely high Mo content and negative Eu anomaly in Sch A represent high oxygen fugacity in the prograde stage. Compared with ore-related porphyries, Sch A has a similar REE pattern, but with higher ΣREE, more depleted HREE and slightly lower (87Sr/86Sr)i ratios. These features suggest that Sch A is genetically related to ore-related porphyries, but extensive interaction with carbonate surrounding rocks affects the final REE and Sr isotopic composition. Sch B shows dark (Sch B-I) and light (Sch B-II) domains under CL imaging. From Sch B-I to Sch B-II, LREEs are gradually depleted, with MREEs being gradually enriched. Sch C has the highest LREE/HREE ratio, which indicates that it inherited the geochemical characteristics of fluids after the precipitation of HREE-rich minerals, such as diopside and garnet, in the early prograde stage. The Mo content in Sch B and Sch C gradually decreased, indicating that the oxygen fugacity of the fluids changed from oxidative in the early stages to reductive in the later, the turbulent Eu anomaly in Sch B and Sch C indicating that the Eu anomaly in the Mamupu scheelite is not solely controlled by oxygen fugacity. The extensive interaction of magmatic-hydrothermal fluids and carbonate provides the necessary Ca2+ for the precipitation of scheelite in the Mamupu deposit. 相似文献
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995.
西藏玉龙铜矿床——鼻状构造圈闭控制的特大型矿床 总被引:8,自引:3,他引:5
文章研究了背斜圈闭构造控制玉龙斑岩-矽卡岩型铜(钼)矿的形成和矿体的分布。通过对成矿体系中各矿体的产出和形态特征、矿床地球化学原生晕分布特征、圈闭构造的古构造应力场恢复等的研究,认为玉龙铜矿的斑岩型(Ⅰ号矿体)、矽卡岩型(Ⅱ、Ⅴ号似层状原生矿体、Ⅴ号矿体上层矿体)、矽卡岩-次生氧化富集型(Ⅱ、Ⅴ号似层状次生氧化矿体)、角岩型(接触带角岩中硫化物矿体)、隐爆角砾岩型等矿体的分布受甘龙拉背斜的南段倾伏端的构造圈闭控制。因此,超大型玉龙铜(钼)矿床的形成与良好的背斜圈闭构造有关。 相似文献
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乌鲁木齐市城区隐伏断裂气体地球化学探测 总被引:1,自引:0,他引:1
利用气体地球化学方法对乌鲁木齐市城区7条隐伏断裂的重点地段进行了11个剖面的定位探测。结果发现,断裂带中地球脱气现象十分强烈,而远离断裂脱气则迅速减弱。11个剖面中9个剖面的土壤气氡在断裂上方异常显著,6个剖面的土壤气汞对断裂反映明显。经过数据数据处理和对比分析,有6条隐伏断裂在地面延伸的位置得到了较精确的判定。应当指出,地下水和人为开挖等因素对城市隐伏断裂的气体地球化学探测有较明显的干扰。 相似文献
998.
额仁陶盖银矿床是次火山热液作用产物。燕山晚期本区受太平洋板块边缘的影响,在已存断裂复活条件下,产生壳幔混合作用形成花岗质岩浆,该岩浆在地下浅处发生强烈的结晶分异作用,形成花岗岩和石英斑岩,两者是同一岩浆不同成岩阶段的产物。石英斑岩是成岩阶段的最后产物。分异作用导致银在成岩期及期后成矿热液中富集。矿床地质地球化学证据表明石英斑岩是矿体的直接母岩。地表大气水在成岩成矿中起着重要作用:①有助于发生基底岩石的部分熔融;②有助于岩浆的结晶分异并导致银在石英斑岩( 浆) 中的富集;③有利于形成大量的矿液。 相似文献
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九十三沟金矿床产于延边复向斜北东端杜荒子-汪清中生代陆相火山断陷盆地东部的石英闪长斑岩内接触带角砾岩中,近南北向断裂构造控制金矿体的产出.成矿物质来自白垩纪浅成侵入体石英闪长斑岩,成矿热液为富含钾质的气水溶液.矿床属岩浆期后中低温热液型金矿床. 相似文献