华北克拉通南缘石炭系本溪组铁-铝黏土矿物质来源: 以河南三门峡大安铝黏土矿床为例^*          下载免费PDF全文

刘学飞  王庆飞  马遥  李中明  赵利华  周智慧  刘百顺  马欣莉 《古地理学报》2020,22(5):965-976

华北克拉通在中奥陶世至晚石炭世期间一直出露地表,经历了长期的风化作用,形成大规模的铁-铝黏土矿,其成矿物源一直是研究的热点,尤其是本溪组底部铁矿和铁质黏土矿与上部铝黏土矿是否为同一来源尚未查清。本研究选取克拉通南缘大安铝黏土矿床作为研究对象,展开微区矿物及元素地球化学组成分析,进一步探讨铁-铝黏土矿物质来源。大安矿床内含矿岩系自下而上包括铁质黏土岩、铝土矿、铝质黏土矿;局部喀斯特高地缺失铝土矿,铝质黏土矿直接覆盖于铁质黏土岩之上。铁质黏土岩在洼地以菱铁矿、黄铁矿和伊利石为主,在隆起区以赤铁矿、伊利石和高岭石为主。铝土矿以硬水铝石、伊利石和锐钛矿为主;铝质黏土矿主要矿物为伊利石。矿物微区分析在黏土矿底部发现大量的碳化硅和少量自然硅、硅铁矿、铬铁矿;区域对比揭示北秦岭造山带内商丹缝合带和二郎坪群中的蛇绿岩为铝黏土矿形成提供了成矿物质。本溪组底部铁质黏土与上部铝黏土矿稳定元素比率(例如Zr/TiO₂、Hf/TiO₂、Nb/TiO₂、Ta/TiO₂)存在明显差异,揭示二者为不同来源: 底部铁质黏土岩和铁矿层为底板碳酸盐岩原地风化的产物;而上部铝黏土矿是异地搬运物,北秦岭造山带在晚石炭世的整体抬升为华北铝黏土矿形成提供了重要的成矿物质。  相似文献   

Deep gold mineralization features of Jiaojia metallogenic belt,Jiaodong gold Province: Based on the breakthrough of 3000 m exploration drilling     

《China Geology》2020,3(3):385-401

Recently, continuous breakthroughs have been made about deep gold prospecting in the Jiaodong gold province area of China. Approximately 5000 t of cumulative gold resources have been explored in Jiaodong, which has thus become an internationally noteworthy gold ore cluster. The gold exploration depth has been increased to about 2000 m from the previous <1000 m. To further explore the mineralization potential of the Jiaodong area at a depth of about 3000 m, the Shandong Institute of Geological Sciences has drilled an exploratory drillhole named “Deep drillhole ZK01” to a depth of 3266 m. Hence, as reported herein, the mineralization characteristics of the Jiaojia metallogenic belt have been successfully documented. ZK01 is, to date, the deepest borehole with an gold intersect in China, and constitutes a significant advance in deep gold prospecting in China. The findings of this study further indicate that the depth interval of 2000 m to 4000 m below the ground surface in the Wuyi Village area incorporates 912 t of inferred gold resources, while the depth interval of 2000 m to 4000 m below the surface across the Jiaodong area possesses about 4000 t of inferred gold resources. The Jiaojia Fault Belt tends to gently dip downward, having dip angles of about 25° and about 20° at vertical depths of 2000 m and 2850 m, respectively. The deep part of the Jiaojia metallogenic belt differs from the shallow and moderately deep parts about fracturing, alteration, mineralization, and tectonic type. The deep zones can generally be categorized from inside outward as cataclastic granite, granitic cataclasite, weakly beresitized granitic cataclasite, beresitized cataclasite, and gouge. These zones exhibit a gradual transitional relation or occur alternately and repeatedly. The mineralization degree of the pyritized cataclastic granite-type ore in the deep part of the Jiaojia metallogenic belt is closely related to the degree of pyrite vein development; that is, the higher the pyrite content, the wider the veins and the higher the gold grade. Compared to the shallow gold ores, the deep-seated gold ores have higher fineness and contain joseite, tetradymite, and native bismuth, suggesting that the deep gold mineralization temperature is higher and that mantle-sourced material may have contributed to this mineralization. ZK01 has also revealed that the deep-seated ore bodies in the Jiaojia metallogenic belt are principally situated above the main fracture plane (gouge) and hosted within the Linglong Granite, contradicting previous findings indicating that the moderately shallow gold ore bodies are usually hosted in the contact zone between the Linglong Granite and Jiaodong Group or meta-gabbro. These new discoveries are particularly significant because they can help correct mineralization prospecting models, determine favorable positions for deep prospecting, and improve metallogenic prediction and resource potential evaluation.  相似文献   

Mineralogy,Fluid Inclusion,and Hydrogen and Oxygen Isotope Studies of the Intrusion‐Related Yangla Cu Deposit in the Sanjiang Region,SW China: Implications for Metallogenesis and Deposit Type     

Li‐Juan Du  Bo Li  Zhi‐Long Huang  Jun Chen  Jia‐Xi Zhou  Guo‐Fu Zou  Zai‐Fei Yan 《Resource Geology》2020,70(1):28-49

The Yangla deposit is an intrusion‐related Cu deposit in the Jinshajiang tectonic belt (eastern Sanjiang region, SW China). Despite extensive studies that have been conducted on this deposit, the relationship between the granitic magma and Cu mineralization is still unclear, and hence, the genesis is debated. To answer this question, we conducted an integrated study of mineralogy, fluid inclusions (FIs), and hydrogen and oxygen (H‐O) isotopes. Three mineralization stages were identified based on the ore textures, alteration zonation, and crosscutting relationships: (i) pre‐ore prograde skarn (stage I), with the garnet and pyroxene dominated by andradite and diopside, respectively; (ii) syn‐ore retrograde alteration (stage II), which is subdivided into the early syn‐ore stage (stage IIa) marked by retrograde hydrated mineral assemblages and significant Fe‐Cu‐Mo‐Pb‐Zn sulfide mineralization, and the late syn‐ore stage (stage IIb) featured by quartz‐calcite veins; and (iii) late supergene mineralization (stage III), which is characterized by secondary azurite and malachite. These results of mineralogy, FIs, and H‐O isotopes indicate that: (i) Cu mineralization has a close temporal, spatial, and genetic relationship with skarn alteration; (ii) the ore fluids were magmatic dominated with late‐stage meteoric water incursion; and (iii) Type‐S (halite‐bearing) and Type‐V (vapor‐rich) FIs coexisted in garnet and clinopyroxene of stage I, indicating that fluid boiling might have occurred during this stage. From stage I to stage IIa, the FI type transformed from Type‐S + Type‐V + Type‐L (liquid‐rich) to Type‐V + Type‐L with the conduct of mineralization and was accompanied by the disappearance of Type‐S, and homogenization temperature and salinity also tended to decrease dramatically, which may be caused by the deposition of skarn minerals. At stage IIa, boiling of the ore fluids still continued due to the change from lithostatic to hydrostatic pressure, which triggered the precipitation of abundant quartz‐Cu‐Mo‐Fe sulfides. Furthermore, fluid mixing between a high‐temperature magmatic fluid and a low‐temperature meteoric water might cause a considerable drop in temperature and the deposition of Cu‐bearing quartz/calcite veins during stage IIb. Hence, we consider the Yangla deposit to be of a skarn type, genetically related to the Mesozoic magmatism in the Sanjiang region.  相似文献   

鄂尔多斯盆地正宁地区三叠系延长组长9油层组成岩作用^*          下载免费PDF全文

沈默  朱筱敏  李程善  张文选  程逸凡  江梦雅 《古地理学报》2020,22(3):539-554

综合利用岩心、铸体薄片、扫描电镜等多种资料,对鄂尔多斯盆地正宁地区三叠系延长组长9油层组储集层的岩石类型、成岩作用类型、成岩相分布特征及主控因素进行了系统研究。延长组长9油层组储集层的岩石类型为细—中粒岩屑质长石砂岩和长石质岩屑砂岩,成岩作用类型主要为压实作用,同时还有绿泥石、方解石、铁方解石及硅质胶结作用,方解石交代作用和少量的溶蚀作用,储集层目前处于中成岩A期。根据层理频率和塑性颗粒含量将岩石划分为高频层理富片状塑性颗粒粉—细砂岩岩石相和低频层理富刚性矿物细—中砂岩岩石相,前者分布于水下分流河道边部,发育压实致密成岩相;后者形成于水下分流河道主河道和河口坝。根据砂体结构可划分为厚层单砂体和厚层多砂体。厚层单砂体为单期形成的河道或河口坝砂体,上部以方解石充填胶结成岩相为特征,下部以绿泥石衬边胶结成岩相为特征;厚层多砂体为多期砂体冲刷叠置形成,发育方解石绿泥石充填胶结成岩相。塑性颗粒含量对压实作用强度影响最大,叠加碳酸盐胶结致使储集层质量变差,而早期绿泥石环边胶结抑制压实作用,是有利储集层发育的重要条件。综合评价表明,延长组长9油层组有利储集层发育于绿泥石衬边胶结相,其次为绿泥石和方解石充填胶结相,最差储集层为方解石充填胶结相和压实致密相。  相似文献   

四川盆地广安地区中二叠统栖霞组岩石特征与沉积环境     

易海永  崔宝琛  王瑶琳  邱玉超  徐胜林  李乾 《吉林大学学报(地球科学版)》2020,50(2):454-464

四川盆地中二叠统栖霞组勘探发现系列油气，资源潜力巨大。但广安地区中二叠统栖霞组的岩石学特征及沉积环境研究薄弱。在野外地质调查的基础上，结合室内岩石学、岩相学等综合分析，对广安地区栖霞组碳酸盐岩岩石特征、沉积相类型及其古地理展布特征进行了系统研究。结果表明：广安地区栖霞组主要发育亮晶颗粒灰岩、亮晶生物碎屑灰岩、微晶生物碎屑灰岩、微晶颗粒灰岩、生物碎屑微晶灰岩、含生物碎屑微晶灰岩和泥晶灰岩7种岩石类型；碳酸盐岩颗粒主要以生物碎屑为主，部分层位发育球粒；古生物化石以三叶虫、腕足和有孔虫为主，同时可见棘皮类和藻类；栖霞组沉积期主要为碳酸盐岩台地沉积环境，其中栖霞组晚期（栖二段）台缘滩和台内滩较为发育，为该区油气成藏提供了有利条件。  相似文献   

勘查植物地球化学在我国不同地球化学景观区的应用现状及展望   总被引：1，自引：0，他引：1       下载免费PDF全文

王天刚  Adrian Fabris  姚仲友  Hou Baohong  赵宇浩  赵晓丹  朱意萍 《华东地质》2020,(1):1-7

勘查植物地球化学是通过分析植物器官来获取成矿元素信息的地球化学方法。我国学者在干旱荒漠区、森林沼泽区、半干旱和湿润半湿润中低山景观区开展了系统的勘查植物地球化学试验,厘定了一批适用于勘查植物地球化学调查的植物,为该方法的推广及应用奠定了良好基础。今后应进一步加强对勘查植物地球化学异常产生的机理、勘查植物地球化学数据库及指南建立、勘查植物地球化学异常遥感应用等方面的研究,更好地利用勘查植物地球化学方法服务矿产勘查工作。  相似文献   

Main active faults and seismic activity along the Yangtze River Economic Belt: Based on remote sensing geological survey     

《China Geology》2020,3(2):314-338

The Yangtze River Economic Belt (YREB) spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and present-day crustal deformation. Active faults and seismic activity are important geological factors for the planning and development of the YREB. In this paper, the spatial distribution and activity of 165 active faults that exist along the YREB have been compiled from previous findings, using both remote-sensing data and geological survey results. The crustal stability of seven particularly noteworthy typical active fault zones and their potential effects on the crustal stability of the urban agglomerations are analyzed. The main active fault zones in the western YREB, together with the neighboring regional active faults, make up an arc fault block region comprising primarily of Sichuan-Yunnan and a “Sichuan-Yunnan arc rotational-shear active tectonic system” strong deformation region that features rotation, shear and extensional deformation. The active faults in the central-eastern YREB, with seven NE-NNE and seven NW-NWW active faults (the “7-longitudinal, 7-horizontal” pattern), macroscopically make up a “chessboard tectonic system” medium-weak deformation region in the geomechanical tectonic system. They are also the main geological constraints for the crustal stability of the YREB.  相似文献   

中国-丝路国家基础设施连通性评估方法与格局     

王成金  陈沛然  王姣娥  李娜 《地理研究》2020,39(12):2685-2704

基础设施互联互通是不同区域之间空间网络形成的支撑,对区际生产要素流动、市场融合和资源配置具有重要作用,也是“一带一路”建设的重点内容和前提条件。立足于综合基础设施网络,以“一带一路”沿线国家/地区为分析地域,设计数理模型,评价了中国与沿线国家的基础设施网络连通性,考察其基本特征与空间格局,然后分别从铁路、公路、航运、通讯、能源等各种基础设施方式的视角,分析了不同基础设施网络的互联互通水平,探讨了基础设施连通的类型分异及其主导因素,凝练基础设施连通的空间模式。主要结论如下：① 从海陆属性来看,岛屿型国家与中国设施连通性最高,其次为综合型国家,内陆型国家最低。对国际区域而言,俄蒙和东南亚地区与中国的设施连通性最高,中东欧地区连通性最低。从国家尺度来看,俄罗斯和越南是与中国设施连通水平最高的国家,巴勒斯坦、东帝汶等5个国家与中国尚未形成设施连通性。从连通方式的构成来看,航运网络的连通性最高,其次为航空和光缆。② 空间距离、连通方式和重大交通走廊共同主导了设施连通性的类型分异。③ “一带一路”沿线国家/地区与中国的设施连通形成了四种典型模式,包括海陆融合型外缘连通模式、陆路通道直接连通模式、陆心内生性低水平连通模式、远距离不均衡连通模式。  相似文献   

黔北正安地区五峰组—龙马溪组页岩气地质特征及有利区预测     

贺永忠  向坤鹏  安亚运  易成兴  杨忠琴  于宁 《中国地质调查》2020,7(3):21-29

为明确黔北正安地区上奥陶统五峰组至下志留统龙马溪组的页岩气地质特征,充分应用页岩气地质调查、重磁电、二维地震、地质调查井及测试分析等工作方法,开展黔北正安地区1:5万页岩气基础地质调查,对五峰组至龙马溪组富有机质页岩的分布、沉积环境、有机地球化学、岩石矿物、储集性能及含气性等特征进行分析研究,结果表明: 研究区五峰组—龙马溪组富有机质页岩为深水陆棚相沉积,主要分布有安场向斜、斑竹向斜和泥高向斜,厚度14.5~55 m,埋深0~3 200 m; 有机碳(TOC)含量1.0%~4.0%,有机质镜质体反射率(R_o)为1.82%~2.23%,有机质类型以Ⅰ型干酪根为主; 岩石主要由石英、长石和黏土矿物组成,脆性矿物含量高,一般大于50%; 孔隙度为2.03%~3.89%,渗透率为0.35×10^-5~1.86×10^-5μm²,表现为低孔、特低渗的特征; 最高含气量为2.88 m³/t,显示出较好的含气性特征。综合分析和评价圈出3个页岩气聚集有利区,分别为安场区块、斑竹区块和泥高区块,这为研究区页岩气进一步勘探开发指明了方向。  相似文献   

Coupling relationship between reservoir diagenesis and hydrocarbon accumulation in Lower Cretaceous Yingcheng Formation of Dongling,Changling fault depression,Songliao Basin,Northeast China     

《China Geology》2020,3(2):247-261

The Lower Cretaceous Yingcheng Formation in the southern Songliao Basin is the typical tight oil sandstone in China. In order to better predict the petrophysical properties of the tight sandstone reservoirs in the Lower Cretaceous Yingcheng Formation, Songliao Basin, Northeast China, the diagenesis and porosity evolution was investigated using a suite of petrographic and geochemical techniques including thin section analysis, scanning electron microscopy, mercury intrusion and fluid inclusion analysis, on a set of selected tight sandstone samples. Combined with the histories of burial evolution, organic matter thermal evolution and hydrocarbon charge, the matching relationship between reservoir porosity evolution and hydrocarbon accumulation history is analyzed. The result showed that the tight sandstone reservoirs characterized of being controlled by deposition, predominated by compaction, improved by dissolution and enhanced by cementation. The hydrocarbon accumulation period was investigated using a suite of hydrocarbon generation and expulsion history, microfluorescence determination and temperature measurement technology. According to the homogenization temperature of the inclusions and the history of burial evolution, Yingcheng Formation has mainly two phases hydrocarbon accumulation. The first phase of oil and gas is charged before the reservoir is tightened, the oil and gas generated by Shahezi source rocks enter the sand body of Yingcheng Formation, influenced by the carrying capability of sand conducting layer, oil and gas is mainly conducted by the better properties and higher connectivity sand body and enriched in the east, which belongs to the type of densification after hydrocarbon accumulation. The second phase of oil and gas charge after densification, which belongs to the type of densification before the hydrocarbon accumulation.  相似文献