福建大田银场型硫-多金属矿地质特征及成矿预测

银场型硫-多金属矿体顺层贮存于船山-棲霞石灰岩中,为晚石炭-早二叠世闽西南海盆地沉积形成"矿源层"的基础上,经印支期、燕山期构造变动,受多次岩浆热液作用富集成的层控矽卡岩型矿床.     

塔里木盆地塔中地区主要构造圈闭形成期分布及成藏意义

通过对塔中地区钻遇奥陶系的60余口井过井地震剖面的精细解释及地震反射截切—上超关系、沉积厚度变化分析,识别出最初形成于晚奥陶世—泥盆纪、石炭纪—早二叠世、早二叠世晚期及中、新生代的四期奥陶系内幕构造圈闭,以及最初形成于石炭纪—早二叠世、早二叠世晚期、晚二叠世、中—晚三叠世及早第三纪末以来的五期石炭系内幕构造圈闭;发现了塔中地区主要构造圈闭的首次形成期呈现由南向北逐渐变晚的总体趋势。构造圈闭形成与成藏配套综合分析表明,该区现今工业性油藏的主要成藏期为二叠纪—早三叠世,而中—晚三叠世及其以后所形成的构造圈闭不利于油藏的形成。认为塔中地区的主力烃源应该来自近邻的满加尔凹陷中—上奥陶统相当于黑土凹组—萨尔干组的层段。     

内蒙古林西地区晚二叠世—早三叠世沉积演化及构造背景

在林西地区新发现的叶肢介和介形虫等化石，证实了大兴安岭南部存在早三叠世地层。这套地层为具有红层性质的河—湖环境产物，与下伏上二叠统林西组沉积有较大的差异。林西组中—下部以海相沉积为主，并发育浊流沉积，反映直到晚二叠世中期大兴安岭南部仍有残余海盆存在，应是造成晚二叠世南北植物化石仍保持区系特征的主因。林西地区晚二叠世—早三叠世的沉积—构造演化特征揭示，大兴安岭南部的晚古生代板块构造活动一直到印支构造旋回才结束。     

内蒙古林西地区晚二叠世一早三叠世沉积演化及构造背景

在林西地区新发现的叶肢介和介形虫等化石，证实了大兴安岭南部存在早三叠世地层，这套地层为具有红层性性质的河一湖环境产物，与下伏上二叠统林西组沉积有较大的差异，林西组中－下部以海相沉积为主，并发育浊流沉积，反映直到第二叠世中期大兴安岭南部仍有残余海盆存在，应是造成晚二叠世南北植物化仍保持区系特征的主因。林西地区晚二叠世一早三叠世的沉积－构造演化特征揭示，大兴安岭南部的晚古生代板构造活动一直到印支构造旋     

敦化隆起东缘晚石炭-早二叠世华夏植物群的发现及其地质意义

根据1998年在大蒜沟组首次发现的Neuropteris、Pecopteris、Cordaites等晚石炭——早二叠世华夏植物群以及与下伏地层的整合接触关系，证明开山屯地区晚石炭——早二叠世为连续的海陆交互相沉积。大蒜沟组华夏植物群的发现，结合开山屯地区晚二叠世华夏植物群的存在，表明该区在晚石炭世——早二叠世华夏植物就已开始分化、繁衍，成为华夏植物群东北亚区不可分割的一部分。     

藏北双湖地区才多茶卡一带构造混杂岩中发现晚泥盆世和晚二叠世放射虫硅质岩

报道了在西藏北部双湖才多茶卡地区新发现的晚泥盆世和晚二叠世放射虫硅质岩,实测剖面的第9层硅质岩以产Neoalbaillella动物群为特征,其中N.ormithoformis,N.optima是晚二叠世长兴阶的2个带化石;第14层硅质岩以产Entactinids动物群为特征,其中Stigmosphaerostylusoumonhaoensis,Triloneheechinata,Archocyrtiumriedeli等主要见于晚泥盆世法门阶。上述2个动物群在西藏尚属首次发现。才多茶卡地区晚古生代放射虫硅质岩的发现为重新认识双湖构造混杂岩带的形成时代、构造环境、“构造带是否东延”等重大地质问题,提供了新的重要资料。     

新疆皮山杜瓦普司格组晚二叠世孢粉的发现

新疆皮山杜瓦剖面普司格组中、上部含丰富的孢子花粉化石，并以双气囊花粉数量占优势为特征。Ｌｕｅｃｋｉｓｐｏｒｉｔｅｓｖｉｒｋｋｉａｅ、Ｔａｅｎｉａｅｓｐｏｒｉｔｅｓｓｐｐ．和Ｇａｒｄｅｎａｓｐｏｒｉｔｅｓｘｉｎｊｉａｎｇｅｎｓｉｓ等国内外晚二叠世典型分子在该组合内出现，表明普司格组的时代并非仅限于以往所普遍认为的早二叠世，亦应包括部分晚二叠世。结合对普司格组上覆和下伏地层的古生物群分析，普司格组的时代为早二叠世中期至晚二叠世中期。     

试论银场型硫—多金属矿的找矿方向

银场型硫-多金属矿体顺层赋存于船山—栖霞灰岩中。是由晚石炭一早二叠世闽西南海盆地沉积形成“矿源层”的基础上,在印支期、燕山期构造变动中,受多次岩浆热液作用而富集成的层控矽卡岩型工业矿床。以此观点指导找矿已见成效。预测从将乐到龙岩间有十几处找矿远景区。     

西金乌兰晚二叠-早三叠世石英砂岩及其大地构造意义

在西金乌兰发现一套晚二叠一早三叠世的石英砂岩和底砾岩,不整合于晚古生代。蛇绿混杂岩之上。沉积构造、结构、成分和粒度分析结果证明这套石英砂岩为海滩亚相石英砂岩;其物源区大地构造背景为克拉通内陆块,沉积环境为稳定陆块边缘,类似被动大陆边缘。表明本区古特提斯洋于早二叠世末一晚二叠世初基本闭合后,在晚二叠一早三叠世处于相对稳定阶段。     

湖南龙潭煤系形成时的大地构造环境

湖南龙潭煤系属于早二叠世末-晚二叠世初期的沉积,沉积类型复杂。江南隆起东南面,以双牌-长寿断裂为界,东西两侧分属不同的物源区。通过对龙潭煤系分布、沉积环境演化、岩相展布、岩浆活动、构造特征、砂岩矿物成分及化学成分的研究认为,早二叠世末-晚二叠世初,区内大地构造环境属于较活动的被动大陆边缘。      

Paleomagnetism of the Late Paleozoic granites of the Angara-Vitim batholith and the host rocks of the Baikal-Patom folded area: Tectonic implications

The paper presents the results of paleomagnetic and geochronological studies of the Late Paleozoic granites of the Angara-Vitim batholith as well as Vendian-Early Cambrian sedimentary rocks and Late Devonian subvolcanic rocks of the Patom margin of the Siberian Platform. Primary and metachronous magnetization in the rocks of the study region was used to calculate an Early Permian (~ 290 Ma) paleomagnetic pole, which is proposed as a reference pole for the Siberian Platform in paleomagnetic reconstructions, plotting of the apparent polar-wander path curve, and other magnetotectonic studies. The published and obtained paleomagnetic data and analysis of the geological data confirm the Late Paleozoic age of the final folding in the Baikal-Patom area. Possible causes of Late Paleozoic deformations and large-scale granite formation in the Baikal-Patom area and Transbaikalia in the Late Paleozoic are discussed.     

An evaluation of slump fold formation using palaeomagnetic techniques

Distorted bedding and soft-sedimentary deformation structures are abundant at the base of the Late Miocene Pannonian sequence, due to rapid basin subsidence and high sedimentary input. A well-preserved slump fold was observed at a depth of 1341 m in Iharosberény I. core hole, SW Hungary. Detailed palaeomagnetic analysis of this fold indicated that the magnetic grains rotated to a certain degree during folding, but the rock has not been remagnetized during and after folding. It is concluded that remanent magnetization was acquired soon after deposition and before folding.     

滇西勐海西定地区南段组褶叠层构造及其研究意义

滇西勐海西定地区,在大地构造上位于西南“三江”造山带南段昌宁-孟连结合带东侧的双江-澜沧俯冲增生杂岩带内。该区分布有一套晚古生代的浅变质碎屑岩系--南段组(DCn)。该套地层既显示层型面状构造型式,又发育有顺层片理、顺层掩卧褶皱、粘滞型石香肠及顺层韧性剪切带等构造形迹,具明显的分层剪切变形、横向构造置换和顺层固态流变特点,构成较典型的褶叠层构造。本文对其构造变形特征进行了系统分析与总结,结合区域构造背景研究成果认为,南段组褶叠层构造总体形成于昌宁-孟连古特提斯洋闭合后同碰撞造山收缩挤压背景下的伸展剪切机制。同时指出,南段组是经过构造改造重建而形成的构造地层单元,应称其为南段岩组;现今露头剖面所见南段岩组岩性组合及厚度只代表改造后构造地层的岩性组合特征及褶叠层的露头厚度,不能完全代表南段组原沉积地层的韵律组合及沉积地层厚度;应按构造地层单位进行划分、填图和研究。褶叠层构造作为浅变质岩区一种普遍的构造型式,是对岩石变形组合特征的客观认识,其构造型式、形成机制、形成层次以及形成时间的研究对分析造山带构造演化过程和深化大陆动力学机制的认识具有科学意义。     

层状硅质岩沉积环境研究的一种新方法（酸溶蚀法）──兼论武昌地区孤峰组沉积环境

武昌地区孤峰组硅质岩主要包括放射虫岩、海绵骨针岩和微晶硅质岩。将这些岩石样品浸入氢氟酸（５—１０％）中１２—２４ｈ，可见清楚的沉积构造。孤峰组上部具丰富的放射虫化石，发育块状层理、条带状层理和三分层理，形成于深水盆地环境；下部具丰富的海绵骨针，发育滑塌构造、粒序层理、水平层理、波状层理，形成于较深水斜坡环境。     

内蒙狼山地区的控矿构造研究

狼山地区中元古代沉积了一套具拉张型过渡壳性质的岩石建造,并混有含矿火山喷发物质。中元古代晚期褶皱回返过程中,经历了多次断裂作用和褶皱变形。在狼山南东缘,顺层滑动断裂和逆冲推覆构造导致了热液蚀变和混合岩化,促使成矿元素迁移到裂隙发育、有利交代作用的白云石大理岩中富集成矿。狼山北西侧,则由于强烈的褶皱叠加作用,促使矿层在褶皱转折端等有利部位加厚,形成厚大工业矿体。从而提出了东升庙型的断裂控矿模式和霍各乞型褶皱控矿模式。     

Infracambrian superimposed tectonics in the Late Proterozoic units of Mount Ablah area, southern Asir Terrane, Arabian Shield, Saudi Arabia

Mount Ablah is a mining prospect, hosted by a dioritic igneous body that is bound to the east by greenschist grade metamorphic rocks and to the west by Ablah group volcano–sedimentary rocks. Rock units of Mount Ablah area were remapped through field investigations, petrological studies, and analysis of enhanced TM Landsat data. Ablah group rocks were divided into lower tuffaceous and upper epiclastic units. The epiclastic unit was divided into three subunits. During remapping, a sliver of serpentinite was discovered, which occurs between the dioritic igneous body and Ablah group rocks. The greenschist grade metamorphic rocks were intruded by Late Proterozoic quartz diorite prior to deposition of Ablah group rocks. The epiclastic unit is an infracambrian molassic unit that filled a graben, known as the Ablah graben. The Mount Ablah area was intruded by post-tectonic granitic rocks and affected by two superimposed F1-F2 folding events, associated with thrust and dextral faults, respectively. The first folding event involved N–S folding and thrusting. Simultaneously, stress partitioning at E–W accommodations zones produced E–W minor folds (F2) and associated E–W dextral faults. The F1–F2 folding events are contemporaneous with the Pan African deformation event, also known as the East African Orogeny (EAO). The EAO is infracambrian in age and culminated in development of the Najd sinistral fault system. The E–W dextral faults were probably reactivated during Cenozoic Red Sea rifting. The Ablah graben's infracambrian sedimentary rocks, such as siltstone, sandstone, and limestone that are mainly bound within the Ablah graben were not deformed prior to F1–F2 folding. Thus, the upper epiclastic unit of the Ablah group rocks is rheologically different from the surrounding greenschist rocks, responded to the late E–W compression in a more ductile manner than the surrounding greenschist rocks. Therefore, the Ablah graben was inverted, refolded, and crosscut by E–W dextral faults during the infracambrian EAO event, prior to development of Najd sinistral fault system, which are evident in Asir Terrane and crosscut Ablah graben.     

The tectonic implications of some small scale structures in the Mona Complex of Holy Isle, North Wales

The rocks of the Rhoscolyn area of Anglesey, North Wales have been subjected to more than one phase of deformation. The result is a complex and often confusing array of minor structures. Using these minor structures, an attempt is made to recognise the major deformation phases that have affected the rocks and to reconstruct the tectonic history of the area. In order to do this it is necessary to consider the deformation of minor structures such as pinch-and-swell; the origin of certain lineations; the problems associated with the buckling of a material that contains two mechanically active planar fabrics, e.g. cleavage and bedding, and the use of pre-existing quartz veins to determine the mechanism of folding.     

The relationship of structures across the Lambian unconformity near Taralga,New South Wales

The structures across the Lambian Unconformity near Taralga show evidence of two, and possibly three, significant episodes of folding. The first, Early to Middle Silurian folding is poorly defined, but may be responsible for initial dips that are reflected in the more complex deformation patterns in the Late Ordovician than in the overlying younger rocks. The second, mid‐Devonian folding produced upright folds trending 10° west of north, and the last, latest Devonian to Early Carboniferous folding produced the meridional Cookbundoon Synclinorium and the regional cleavage. No cleavage was associated with the first two episodes of folding in the area studied. The angular discordance across the Lambian Unconformity caused by mid‐Devonian folding is much greater than in the northeastern Lachlan Fold Belt, and reflects the increasing intensity of mid‐Devonian folding southward. The tight, slightly overturned profile of the Cookbundoon Synclinorium reflects an intensity of latest Devonian to Early Carboniferous folding similar to that found in the northeastern Lachlan Fold Belt, but the intensity of this folding decreases further south.     

西藏岗巴-东亚地区永珠组沉积时代及沉积环境

前人对冈底斯成矿带的研究主要集中在新生代岩浆岩及其矿产方面,而关于其晚古生代沉积地层鲜有报道.近年来的冈底斯成矿带西段1:5万区域地质调查工作显示其出露大量的晚古生代永珠组的沉积地层.从野外地质调查、岩石学、典型沉积构造、孢粉化石、粒度分析、沉积地球化学等方面对永珠组展开了研究,结果表明,永珠组形成于晚石炭世（C₂）Bashikirian-Moscovian期（中、晚巴什基-莫斯科期）,孢粉化石中裸子植物花粉占优势（80%）、蕨类植物孢子居从属地位（20%）.永珠组发育大量的水平层理、平行层理、粒序层理、浊积纹层、滑塌变形构造和鲍马序列等典型沉积构造.永珠组沉积岩表现出高Si（SiO₂为60.94%~76.24%）、Al（Al₂O₃为9.24%~13.20%）、K（K₂O为2.81%~5.47%）和低Mg（MgO为1.32%~2.82%）、Ca（CaO为1.19%~2.78%）、Na（Na₂O为0.2%~1.87%）的主量元素特征,且具有明显高的FeO含量（3.31%~6.67%）和明显低的Fe₂O₃含量（0.14%~0.65%）.稀土元素总量（174.24×10-6~278.39×10-6）较高,经北美页岩标准化的稀土元素配分模式不具Ce异常,Ce/Ce*=0.94~1.03.微量元素表现出Rb、Th、K等元素富集和Ba、U、Nb、Ta、Sr、P、Ti等元素亏损的特征.永珠组形成于大陆边缘环境的陆坡-深水盆地,为暖温气候、中盐度环境下的海退沉积产物,是古特提斯在冈底斯地区的沉积响应.      

上扬子西南缘早三叠世嘉陵江组物源分析和构造环境:沉积学、重矿物电子探针和U- Pb年龄的限定

上扬子西南缘地区广泛分布峨眉山玄武岩,受其影响在中带金阳和外带荥经地区嘉陵江组发育滨岸和潮坪环境沉积物。本文在交错层理恢复的物源方向基础上,根据重矿物组成、重矿物电子探针和碎屑锆石测年结果,综合分析不同区域嘉陵江组物源区,进而探讨嘉陵江组形成的构造环境。嘉陵江组砂岩碎屑重矿物锆石、磷灰石、铬尖晶石等指示物源主要来自于岩浆岩,且自中带至外带基性岩浆岩所占比重逐渐减少。电气石电子探针分析显示,二者物源主要来自于贫锂花岗岩和变质砂岩、板岩。铬尖晶石显示,金阳地区物源来自峨眉山玄武岩和洋岛岩浆岩类岩石,荥经物源主要来自洋岛岩浆岩类岩石,个别为峨眉山玄武岩。碎屑锆石表明,嘉陵江组物源主要来自于新元古代岩浆岩和晚二叠世峨眉山玄武岩,前者经历再搬运。综合物源分析表明,嘉陵江组物源主要来自康滇古陆,岩石类型主要为峨眉山玄武岩和砂岩等。沉积序列和物源分析表明,嘉陵江组反映了沉积物蚀顶过程。结合地震资料、大火成岩省的分析成果表明,嘉陵江组形成于火山型裂谷边缘。