Distribution and characteristics of volcanic reservoirs in China

About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime.     

浙江早白垩世晚期火山活动与火山—沉积岩系地层划分

系统研究浙江下白垩统“永康群”、“横山组”火山—沉积岩系地层层序，岩石组合，古生物，火山岩同位素年龄和岩石化学、地球化学资料表明：浙江永康群中火山岩成岩时间在距今115～100Ma之间，属早白垩世晚期。火山岩具双峰式特征。大致以江山—上虞和景宁—宁海一线为界，分成衢州—诸暨、永康—宁波、文成—临海3个火山活动带，自西向东火山活动渐次增强，火山活动起始时间稍有后移。根据火山—沉积岩系岩石组合，古生物群特征，火山岩同位素年龄及古地磁资料，提出横山组、中截组、永康群和文成群是早白垩世晚期同一构造发展阶段的产物。     

Division and correlation of Yixian Formation in western Liaoning,China

The Yixian Formation is a series of volcanic-sedimentary rocks in Biepiao area of Liaoning Province.It is mainly composed of basic and intermediate-basic volcanic lava,pyroclasts and terrestrial sedimentary rocks.Based on the regularity of volcanic activity,the Yixian Formation was divided by the present authors into four members in ascending order:the first member is of basal conglomerate,basic and intermediate-basic volcanic rocks;the second member is of lake phrase sedimentary rocks,or in another word,precious fossil-rich sedimentary beds;the third is of basic volcanic rocks;and the fourth is of upper conglomerate.Field mapping and comprehensive study also indicate that there are abundant vertebrate fossils (mainly of Psittacosaurus) in the first member of the Yixian Formation,and the Jehol Biota (including Sinosauropterxy,Confuciusorns sanctus,Archaefructus,etc.) is yielded in the second member of Yixian Formation.From west to east,the volcanic activity of Yixian Formation changed regularly from early to late,and from basic and intermediate-basic to acid (alkali).     

胶北臧家庄盆地中生代火山岩及火山活动特征

通过对胶北臧家庄盆地中生代火山岩系的构造位置、产出状态、岩石特征、地球化学特征、相序列组合及同位素年龄等资料的综合分析，结合区域构造特征，认为其属中国东部中生代火山岩带之桃村—莱阳火山 沉积盆地构造组成部分；岩石类型为玄武岩、安山岩、英安岩及流纹岩等，属钙碱性系列，按相序列可划分为安山质岩系、英安质岩系及凝灰质粘土岩三个相组；构成两个火山旋回。     

The Cenozoic Volcanoes in Northeast China

There are more than 600 Cenozoic volcanic cones and craters with abeut 50 000 km2of lava flows in northeast China, which formed many volcanic clusters and shown the features of the continental rift - type volcanoes. Most volcanic activities in this area, especially in the east part of Songliao graben, were usually controlled by rifts and faults with the main direction of NE / NNE in parallel and become younger from the central graben towards its both sides, especially to the east continental margin. It is revealed that the volcanism occurred in northeast China was as strong as that occurred in Japan during the Miocene and the Quaternary. The Quaternary basalt that is usually distributed along river valley is called "valley basalt"while Neogene basalt usually distributed in the top of mounts is called "high position basalt". These volcanoes and volcanic rocks are usually composed of alkaline basalts with ultramafic inclusions, except Changbaishan volcano that is built by trachyte and pantellerite.     

The Cenozoic Volcanoes in Northeast China

There are more than 600 Cenozoic volcanic cones and craters with about 50 000 km2 of lava flows in northeast Chi-na, which formed many volcanic clusters and shown the features of the continental rift-type volcanoes. Most volcanic activi-ties in this area, especially in the east part of Songliao graben, were usually controlled by rifts and faults with the main direc-tion of NE / NNE in parallel and become younger from the central graben towards its both sides, especially to the east conti-nental margin. It is revealed that the volcanism occurred in northeast China was as strong as that occurred in Japan during the Miocene and the Quaternary. The Quaternary basalt that is usually distributed along river valley is called "valley basalt" while Neogene basalt usually distributed in the top of mounts is called "high position basalt". These volcanoes and volcanic rocks are usually composed of alkaline basalts with ultramafic inclusions, except Changbaishan volcano that is built by tra-chyte and pantellerite.     

The Cenozoic Volcanoes in Northeast China

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青海省都兰县哈茨谱山北铜铅银金多金属矿矿床地质特征及成因探讨

哈茨谱山北矿区位于青海省都兰县东部,其大地构造位置处于秦祁昆晚加里东造山系、东昆北造山带、祁漫塔格-都兰造山亚带的东段,区内构造活动和岩浆活动强烈。铜铅银金多金属矿矿床赋存于晚志留世英云闪长岩中,矿体产出严格受断裂构造控制,并受火山热液的叠加。矿体形态呈脉状、透镜状。通过对矿区内地层、控矿构造、侵入岩、矿体特征和矿石质量的分析论述,认为该矿床为中—低温火山期后热液型铜铅多金属矿床。     

南天山榆树沟—铜花山构造混杂体雏议

榆树沟—铜花山构造混杂体,东西长大于70km,南北宽约25km,是由不同规模的外来和原地岩块组成的。蛇绿岩套则强烈地混杂在变质基质之中,它们通过韧性剪切带或断裂与不同时代的外来岩块相接触,而它们之间无任何热接触现象。蛇绿岩套层序由上而下是沉积岩、火山岩、火成堆积岩和地幔橄榄岩。根据岩石学特征,组成这些外来和原地岩块的奥陶系、志留系、泥盆系和蛇绿岩,形成于弧-盆和活动大陆边缘环境。构造混杂体形成一系列北西西向推覆构造。蛇绿岩与原地岩块通常构成向南和向北推覆的低角度冲掩断层。晚期推覆构造使其更加复杂化。     

山东省区域地球物理场

山东省各岩石磁性及密度参数基本可分为高、中、低 3类。山东省磁性结晶基底为泰山岩群、荆山群、胶东岩群、胶南岩群。以沂沭断裂带为界 ,山东省区域地球物理场分为鲁东区和鲁西区。鲁东区进一步划分为 3个次级区 ,即北部区、中部区和南部区。鲁西区进一步划分为 5个次级区 ,即鲁北重磁缓变区、鲁西南重高磁高区、中部弧形重磁场区、鲁西中部重低磁高区、鲁中南条带状重磁场区。各区地球物理场由于地质原因各具特点。山东省莫氏面总体呈东浅西深的缓变带 ,在该缓变带的背景上 ,呈周边地区条带状幔隆、中部幔坳的特征。山东省居里面呈近南北向带状分布 ,有德州聊城菏泽隆起带、滨州淄博滕州深坳带、蓬莱海阳千里岩响水隆起带。鲁中隆起北部碰撞带为山东省特殊的构造地带 ,其特征为侵入岩体沿该带断续出现、岩体围岩或岩体内铜及多金属矿化较为普遍、地热田沿该带时有分布、地形上为南部山区和北部平原的分界地带。胶莱盆地内 ,蓼兰—高密缺失莱阳群层位 ;中生代早期 ,盆地东北部与西南部是盆地的沉积中心 ,至晚期盆地中心北移 ,第三纪沉积中心则为平度蓼兰附近 ;盆地较深部位位于诸城凹陷、平度凹陷。胶莱盆地的次级构造单元可划分为 11个 ,七级镇构造带控制了胶莱盆地的成生和发展。山东省岩浆岩通常表     

山东省区域地球物理场

山东省各岩石磁性及密度参数基本可分为高、中、低3类.山东省磁性结晶基底为泰山岩群、荆山群、胶东岩群、胶南岩群.以沂沭断裂带为界,山东省区域地球物理场分为鲁东区和鲁西区.鲁东区进一步划分为3个次级区,即北部区、中部区和南部区.鲁西区进一步划分为5个次级区,即鲁北重磁缓变区、鲁西南重高磁高区、中部弧形重磁场区、鲁西中部重低磁高区、鲁中南条带状重磁场区.各区地球物理场由于地质原因各具特点.山东省莫氏面总体呈东浅西深的缓变带,在该缓变带的背景上,呈周边地区条带状幔隆、中部幔坳的特征.山东省居里面呈近南北向带状分布,有德州聊城菏泽隆起带、滨州淄博滕州深坳带、蓬莱海阳千里岩响水隆起带.鲁中隆起北部碰撞带为山东省特殊的构造地带,其特征为侵入岩体沿该带断续出现、岩体围岩或岩体内铜及多金属矿化较为普遍、地热田沿该带时有分布、地形上为南部山区和北部平原的分界地带.胶莱盆地内,蓼兰-高密缺失莱阳群层位;中生代早期,盆地东北部与西南部是盆地的沉积中心,至晚期盆地中心北移,第三纪沉积中心则为平度蓼兰附近;盆地较深部位位于诸城凹陷、平度凹陷.胶莱盆地的次级构造单元可划分为11个,七级镇构造带控制了胶莱盆地的成生和发展.山东省岩浆岩通常表现为强磁性、低密度,但基性程度高的岩体磁性高、密度亦高,酸性程度高的岩体磁性低、密度低.     

Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions.Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ12C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb,suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.     

Characteristics of helium isotopes in natural gas and its tectonic implication in Bohai Bay Basin

1 INTRODUCTION Helium is a trace element in natural gas and the lightest element of all rare gases. It is formed during natural nuclear processes and it is chemi- cally stable. Because of its strong diffusibility and permeability, it is used as a very sen…     

The Cretaceous of the Eastern Bangong-Nujiang Suture Zone (Tibet):Tectono-Sedimentation

The ophiolite-bearing Bangong-Nujiang zone (BNZ) traversing central Tibet from east to west separates the Qiangtang block in the north from the Lhasa block in the south. The Cretaceous of the area includes Chuanba Formation (K1c), Duoba Formation (K1d), Langshan Formation (K1l) and Jiangba Formation (K2j). The K1c is composed of black shale,sandy pelite, siltstone, sandstone, coal beds and volcanic rocks, of shallow marine facies. The K1d consists of terrestrial siliciclastics intercalated with some calcareous sandstone beds bearing Orbitolina sp. indicating marine influence. The K1j is carbonate platform deposits of shallow marine and lagoon. The K2j is characterized by terrestrial thick massive red conglomerate. An active margin related to B-subduction zone is considered to be the geological setting of the Cretaceous sedimentation.     

The Cretaceous of the Eastern Bangong-Nujiang Suture Zone (Tibet):Tectono-Sedimentation

1IntroductionThe Tibet plateau consists of terranes which were accreted in a southward-younging succession from Late Permian to Mid-Eocene (Dewey etal., 1988; Mattern etal., 1998; Mattern and Schneider, 2000). The Songpan-Ganzi terrane was accreted to the Kunlun during Late Permian along Kunlun-Qin-ling suture. The Qiangtang block was added onto the Songpan-Ganzi terrane at the Jinsha suture dur-ing Late Triassic-Early Jurassic. The Lhasa block became attached to the Qia…     

对遂昌治岭头金矿的几点看法

治岭头金矿在构造研究,成矿及其时代等问题,一直存在不同看法,90年代前绝大多数同志认为,该处属较老时代的金矿。目前已由不同阶段成矿到与火山热液及地下热水成矿有关的几种较年青金矿的看法。本文从构造分析、火山周边断裂矿化及矿石绝对年龄样成果,提出该区金矿与火山热液关系的密切,成矿时代属燕山晚期（相当中下白垩世）。     

沂水县北躲庄铁矿地质特征

山东省沂水县北躲庄矿区处于汞丹山凸起之上,其西侧为马站-苏村凹陷,东侧为莒县凹陷。区域地层分布较齐全,构造复杂,岩浆岩发育。该矿区地层简单,只出露新太古代泰山岩群柳杭组地层包体和新生代第四纪松散堆积物;构造有韧性剪切带和脆性断裂构造2种;岩浆岩发育,主要分布有古元古代条花峪单元、松山单元、三官寨单元。铁矿体赋存于泰山岩群柳杭组的顶部,共圈定了7个矿体,矿体呈层状产出,倾向110°~120°,倾角47°~82°。TFe品位29%~37%。其矿体成因为沉积变质型铁矿。     

辽北法库城子山一带硅灰石矿床地质特征

法库城子山一带硅灰石矿床分布在吉黑地槽南缘调兵山背斜，赋存于早古生代富拉堡子岩组与岩体接触带附近，属接触变质型矿床。区域上构成了东、西两个硅灰石矿带。矿石类型有： 致密块状硅灰石－ 方解石－ 石英型， 硅灰石－ 石英型， 巨晶硅灰石－ 方解石型等三种类型。其主要围岩蚀变为硅灰石化、硅化、碳酸盐化、绿泥石化及角岩化，局部见矽卡岩化。富硅灰岩－ 三叠世侵入岩－ 构造裂隙系统是主要控矿因素。     

西天山温泉布拉格达瓦一带托斯库尔他乌组沉积特征及构造环境分析

西天山温泉地区广泛发育泥盆—石炭纪火山—沉积地层,布拉格达瓦一带出露的托斯库尔他乌组发育一套由滨海间夹陆相—滨浅海相—浅海相过渡的碎屑岩夹火山碎屑岩的沉积建造,沉积物源主要为中酸性火山岩,碎屑颗粒沉积速度较快,属于近源沉积,蚀源区构造环境具活动性质,形成于未切割的活动岛弧。火山岩呈夹层、透镜体状分布于托斯库尔他乌组地层中,火山作用具周期性间歇喷发的特征,岩相表现为爆发—喷溢—沉积—爆发—沉积—爆发的周期性特点。火山岩属钙碱性岩石系列,火山岩浆对应的俯冲深度为上地幔。火山岩微量元素Nb,Sr,P,Ti,Ba为亏损型,Th,Zr元素富集,与岛弧环境密切相关;Nb/Ta为11.96~15.19,略低于原始地幔值,Zr/Hf为30.17~38.20,与原始地幔值相近。稀土总量∑REE为(186.57~208.58)×10^-6,轻重稀土比值为5.38~6.13;(Ce/Yb)_N为3.90~4.48,(La/Yb)_N为4.67~6.70,δEu为0.28~0.49,属于轻稀土富集型,显示为负铕异常。根据沉积物源区分析及主、微量元素特征,结合区域构造背景,认为晚泥盆世托斯库尔他乌组沉积建造所反映的构造环境为消减带俯冲碰撞的岛弧环境。     

Recognition and Significance of Volcanic Rocks of the Anda Depression of the Songliao Basin in Jurassic-Cretaceous

In the northern Songliao Basin, volcanics are fre-quently found and related closely to tectonic activi-ties during Early Cretaceous. The lava is mainly erupted along deep faults and distributed along the margine of the faulted depression. In deep part of Xujiaweizi area, natural gas exploration has been very successful, such as in the well Wang 9-12, well Shengshen 101 and well Fangshen 9 which are all highly-yield gas wells. Anda fault depression is lo-cated in the north of Xujia…