Eastward extrusion and northward expansion of the Tibetan plateau—discussions for the deep processes of the plateau uplift     

Zhou Ye  Rui Gao  Qiusheng Li  Xiao Xu  Xingfu Huang  Xiaosong Xiong  Wenhui Li 《《地质学报》英文版》2018,92(Z1):79-79

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Forward solver for deep earth exploration and induction logging using custom built Edge-Element FEM technique     

Mingyang Lu  Wuliang Yin  Shijie Sun  Jiangtao Sun  Zhang Cao  Lijun Xu 《《地质学报》英文版》2018,92(Z1):302-304

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安哥拉罗安达湿陷性砂的载荷试验研究          下载免费PDF全文

唐国艺  唐立军  刘智  刘争宏  于永堂  乔虎 《水文地质工程地质》2018,(5):108-108

安哥拉罗安达广泛分布的湿陷性砂（Quelo砂）,是一种对水十分敏感的特殊砂土,具有浸水后强度降低,并产生湿陷变形的特殊性质,由于缺乏相应的资料和工程经验,其湿陷程度和承载特性是评价的难点。本文通过天然和浸水饱和条件下的载荷试验,实测和研究了罗安达Quelo砂的湿陷变形特点和不同条件下的承载力特征。试验研究结果显示,罗安达Quelo砂是一种湿陷程度为轻微—中等的湿陷性土;Quelo砂的承载力对水分异常敏感,地基土含水率的微小变化即可导致承载力数倍的降低,且饱和后的承载力较小,试验场地浸水饱和后的地基承载力深度修正系数可取1.07。试验表明,在工程实践中考虑地基土含水率变化对地基承载力的影响,不采用消除地基全部湿陷量或部分湿陷量的方法,而将红砂地基当做一般地基进行设计是可行的。  相似文献   

锚固岩体的单轴压缩力学特性及其各向异性特征分析          下载免费PDF全文

熊良宵  虞利军 《水文地质工程地质》2018,(4):46-52

通过对含有锚杆的水泥砂浆试件进行单轴压缩试验,系统地研究了锚杆的布置方式对试件强度和变形特性的影响。研究结果表明:(1) 当锚杆横截面的连线呈直线或者正方形时,随着锚杆数量的增加,试件的抗压强度、弹性模量均会逐渐增加,试件峰值应变的变化没有固定规律;(2) 当锚杆横截面的连线呈直线时且试件中的锚杆数量相同时,荷载方向垂直于锚杆横截面的连线时试件的抗压强度和弹性模量,大于荷载方向平行于锚杆横截面的连线时试件的抗压强度和弹性模量。  相似文献   

煤层气U型对接井施工关键技术探讨          下载免费PDF全文

熊亮  张小连 《探矿工程》2018,45(2):33-35,51

煤层气地面排采先后经历了常规直井、常规定向井、U型井以及羽状分支井等阶段,其中U型井具有同步排采,占地少、最大限度沟通煤层裂隙等优点而逐渐成为当今煤层气地面排采的新宠。以YQ01井组为例,对U型对接井施工中难点问题进行梳理,提出了各主要施工阶段需要注意事项及技术措施,解决了井眼轨迹控制难、复杂情况高发、水平井与直井连通精度高等问题。节省了钻井成本,为后续煤层气U型对接井施工提供了技术借鉴。  相似文献   

四川盆地东部垫江凹陷三叠系嘉陵江组岩盐氯同位素特征与成钾指标研究   总被引：1，自引：0，他引：1  

唐清敏  张雄  朱正杰  魏玉燕  刘永旺  刘振 《地质学报》2018,92(8):1671-1679

垫江凹陷位于四川盆地东部,是四川盆地三叠纪时期重要的成盐凹陷之一,但当时古卤水是否达到钾盐沉积阶段,是否具备形成海相钾盐的良好条件,一直存在争议。本文通过对垫江凹陷长平3井、高探1井和ZK001井嘉陵江组岩盐样品进行化学成分分析,以及对长平3井典型岩盐样品进行氯同位素分析来判断古卤水沉积阶段和成钾条件。结果发现垫江凹陷三叠系嘉陵江组岩盐δ37 Cl值均为负值,均小于-0.32‰,最低达到-1.18‰,绝大部分岩盐样品溴氯系数大于0.31,有很大一部分样品溴氯系数超过0.45,进一步表明垫江凹陷在嘉陵江期古卤水浓缩已达到钾石盐析出阶段,与岩盐包裹体成分分析结果一致。综合气候-物源-构造因素,认为垫江凹陷三叠纪嘉陵江期气候条件炎热,物质来源丰富,存在次级凹陷,古构造条件优越,具备良好的成钾潜力。  相似文献   

Middle Jurassic–Early Cretaceous tectonic evolution of the Bayanhushuo area,southern Great Xing’an Range,NE China: constraints from zircon U–Pb geochronological and geochemical data of volcanic and subvolcanic rocks     

Qing-Bin Guan  Bin Wang  Xiong Wang  Xing-An Wang  Qiang Shi 《International Geology Review》2018,60(15):1883-1905

This study presents new zircon U–Pb geochronology, geochemistry, and zircon Hf isotopic data of volcanic and subvolcanic rocks that crop out in the Bayanhushuo area of the southern Great Xing’an Range (GXR) of NE China. These data provide insights into the tectonic evolution of this area during the late Mesozoic and constrain the evolution of the Mongol–Okhotsk Ocean. Combining these new ages with previously published data suggests that the late Mesozoic volcanism occurred in two distinct episodes: Early–Middle Jurassic (176–173 Ma) and Late Jurassic–Early Cretaceous (151–138 Ma). The Early–Middle Jurassic dacite porphyry belongs to high-K calc-alkaline series, showing the features of I-type igneous rock. This unit has zircon ε_Hf(t) values from +4.06 to +11.62 that yield two-stage model ages (T_DM2) from 959 to 481 Ma. The geochemistry of the dacite porphyry is indicative of formation in a volcanic arc tectonic setting, and it is derived from a primary magma generated by the partial melting of juvenile mafic crustal material. The Late Jurassic–Early Cretaceous volcanic rocks belong to high-K calc-alkaline or shoshonite series and have A₂-type affinities. These volcanics have ε_Hf(t) and T_DM2 values from +5.00 to +8.93 and from 879 to 627 Ma, respectively. The geochemistry of these Late Jurassic–Early Cretaceous volcanic rocks is indicative of formation in a post-collisional extensional environment, and they formed from primary magmas generated by the partial melting of juvenile mafic lower crust. The discovery of late Mesozoic volcanic and subvolcanic rocks within the southern GXR indicates that this region was in volcanic arc and extensional tectonic settings during the Early–Middle Jurassic and the Late Jurassic–Early Cretaceous, respectively. This indicates that the Mongol–Okhotsk oceanic plate was undergoing subduction during the Early–Middle Jurassic, and this ocean adjacent to the GXR may have closed by the Late Middle Jurassic–Early Late Jurassic.  相似文献   

东沙隆起南缘第四系等深流沉积特征及成因机制     

江宁  何敏  刘军  庞雄  张向涛  薛怀艳 《沉积学报》2018,36(1):120-131

珠江口盆地东沙隆起南缘深水陆坡区（水深约900~2 600 m）是西北太平洋和南海水体交换的活跃区域,发育了类型丰富的等深流沉积体,但等深流沉积特征和成因机制尚不明确,相关研究仍缺乏足够证据。通过区域地震资料和ODP1144站钻井数据分析发现,该区第四系地层中可识别5种深水底流成因的等深流沉积:涂抹形漂积体、伸长形-丘形漂积体、限制形漂积体、沉积物波以及席状漂积体。根据等深流沉积特征、发育类型以及分布范围,从陆坡到深海平原大致依次出现涂抹形漂积体、伸长形-丘形漂积体、限制形漂积体和席状漂积体,而具有波状沉积底形的沉积物波主要发育于陆坡区。东沙隆起南缘第四系等深流沉积的形成、演化受控于多种因素,其中主控因素包括:西北太平洋与南海中-深层水体的"双层"环流结构、科里奥利力的"右偏"效应、冰期-间冰期海平面升降所诱导的底流与重力流交互作用机制以及新构造运动时期火山活动对海底地貌的改造。  相似文献   

Zircon U-Pb Geochronology,Geochemistry and Petrogenesis of Early Cretaceous A-type Granites in the Mikengshan Area,Southern Jiangxi ProvinceEI北大核心CSCD     

Liang H.  Guo H.  Wang Q.  Xiong X.  Ou Q.  Zeng J.  Gou G.  Hao L. 《大地构造与成矿学》2018,(4):746-758

In the Mikengshan-Yanbei area, a special region for the tin mineralization in South China, there are some Yanshanian granites and porphyries and associated porphyry tin deposits (e.g., Yanbei). Although the tin mineralization is closely associated with the granitoids magmatism, the age and petrogenesis of the granites remain controversial. The Mikengshan pluton, which intrudes into the rhyolitic tuff and pyroclastic rocks of the Upper Jurassic Jilongzhang Formation, is the largest one in Mikengshan-Yanbei area and mainly consists of K-feldspar bearing granites. In this study, we report new age and geochemical data for the Mikengshan K-feldspar bearing granites. LA-ICP-MS zircon U-Pb age dating shows that they were generated in the Early Cretaceous (~138 Ma). They have high SiO2 (74.42% to 76.69%), low Al2O3 (12.39% to 13.49%) and Mg# (11 to 19), and negative Eu, Sr and Ba anomalies, and are rich in potassium (most K2O/Na2O=1.37 to 1.94) and high field strength elements (HFSEs), and are weakly peraluminous (A/CNK=1.03 to 1.1) with high 10000×Ga/Al ratios (3.46 to 4.96) and slightly high zircon saturation temperatures (807 ℃ to 817 ℃), showing the characteristics of the typical A-type granites. Moreover, they have high Rb contents 842×10-6 to 1295×10-6, Rb/Sr (90 to 255) ratios and show rare earth elements (REE) tetrad effect, which are similar to those of high fractionated granites. Thus, we suggested that the Mikengshan K-feldspar bearing granites are high fractionated and aluminous A-type granite. Their slightly high εNd(t) values (-3.4 to -4.6) indicate that the mantle components should have played a role during their formation. Taking into account regional igneous rocks and tectonic setting data, we suggest that the Mikengshan K-bearing granites were formed in an extensional setting, which was probably related to the roll-back of the subducted Paleo-Pacific plate. © 2018, Science Press. All right reserved.  相似文献   

黔西南"断控型"金矿床的找矿模式与勘探评价方法——以丫他金矿床为例     

张伟  季国松  廖国忠  张启跃  高慧  熊伟  夏时斌  杨剑  李华 《地质学报》2021,95(12):3961-3978

黔西南地区以丫他、烂泥沟、百地等为代表的"断控型"金矿床地处深水槽盆浊积岩沉积建造,其中烂泥沟金矿床埋深达1000m且尚未圈闭,显示了该类型矿床巨大的深部隐伏矿找矿潜力.本文基于丫他幅1∶5万矿产地质调查和以丫他金矿为典型矿床的大比例尺找矿方法试验成果,分析了本区"断控型"金矿床的地质和成矿特征,对比研究了地质、物探、化探、遥感多尺度组合异常特征,总结了"断控型"金矿床的勘探找矿模式、靶区优选依据和定量预测评价要素,并利用成矿地质体参数法对丫他金矿床及外围0～2 km深度的潜在资源量进行了定量估算.研究结果认为区域性深切断层及其浅表贯通的次级断层、裂隙网络是该区重要的控矿要素之一,不同尺度、不同组合的物化遥异常对各级别构造的规模、产状等存在响应关系.对丫他金矿床外围及其深部的资源潜力进行了定量评价,预测0～2000 m空间仍存在约112.983 t的金资源潜力.化探、遥感浅表组合异常和区域重力、电法剖面相结合的勘查技术方法,能够为本区找矿靶区的优选提供多学科交叉证据支撑,其勘探技术、评价方法值得在黔西南其他找矿远景区推广,能够为后续商业性开发投入指明方向、减少风险.  相似文献