共查询到19条相似文献，搜索用时 875 毫秒
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本区经历四期变质作用,太古宙上壳岩系麻粒岩相变质、晚太古宙英云闪长岩高角闪岩相变质、早元古宙紫苏花岗岩类低角闪岩相变质和元古宙绿片岩相变质。麻粒岩相变质期可分三个阶段,早期角闪岩相、峰期麻粒岩相和晚期角闪岩相,其P-T-t轨迹为逆时针,与IBC型轨迹相似。导致麻粒岩相变质作用的热源为英云闪长质岩浆的垫托作用,形成于岛弧或活动大陆边缘。区内广泛发育的钾长花岗岩与晚太古宙高角闪岩相变质作用晚期的深熔作用有关。 相似文献
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根据变质作用分类研究的历史回顾和最新进展,本文介绍了一个试行的、较系统的变质作用分类方案,可分为局部性的变质作用和区域性的变质作用两个大类9个类型.局部性的变质作用包括以下5个类型:(1)接触变质作用,包括热变质作用、接触交代变质作用和高热变质作用3个亚类;(2)低-中-高温动力变质作用,包括低-中-高温韧性剪切带变质作用和温压递进逆冲断层变质作用2个亚类;(3)冲击变质作用;(4)水热变质作用;(5)燃烧变质作用.区域性的变质作用可分为以下4个类型:(6)早前寒武纪克拉通基底变质作用-低中压-中高温区域变质作用,可分为5个亚类,分别是低-中压角闪岩相变质作用、低-中压麻粒岩相变质作用、低-中压角闪岩相-麻粒岩相变质作用、低-中压绿片岩相-角闪岩相递增的变质作用和区域超高温麻粒岩相变质作用;(7)造山带变质作用,可分为3个亚类,分别是低温-低压区域动力变质作用、碰撞造山变质作用和深俯冲高压-超高压区域变质作用;(8)埋深变质作用;(9)洋底变质作用. 相似文献
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以佛坪穹隆为核心,（麻粒岩相）－高角闪岩岩相－低角闪岩相变质相带呈同心环带状依次向外展布;研究表明,其为加里东－海面期由于地幔上隆导致基底减压熔而形成局部隆起飞并引起上部盖层分层剪切－滑脱作用过程变质作用所发生;变质峰期温、压力成局部隆起,并引起上部盖层分层剪切－滑脱作用过程变质作用所发生;变质峰期温－压力分别可达８２９℃和０．７５Ｇｐａ。但变质峰期滞后迹形峰期。在变质变形过程中基底的隆升分幅度可 相似文献
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在分析烟台北部芝罘群主要变质岩类的变质矿物共生组合，变质相系及构造岩等特征的基础上，对该群变形，变质作用及演化特征进行了探讨。认为该区芝罘群曾经历1期韧性变形作用和4期变质作用（古元古代高角闪岩相，中元古代早期低角闪岩相，中元古代晚期高绿片岩相及新元古代低绿片岩相变质作用）。 相似文献
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江绍断裂两侧早元古代变质基底特征及形成的构造环境 总被引：3，自引：0，他引：3
江绍断裂东侧出露的早元古代变质基底以一套遭受中压型角闪岩相区域热流变质作用改造的黑云斜长变粒岩、云母石英片岩为主，夹少量斜长角闪岩和大理岩，已遭受４期构造变形作用改造，从原岩建造和主要岩类地球化学特点推测它可能形成于大陆或大陆边缘类似于内硅铝盆地环境。江绍断裂西侧早元古代变质基底则以星子杂岩为代表，由变粒岩、浅粒岩、（十字一石榴）云母片岩和少量斜长角闪岩组成，已遭受中压型高绿片岩相一低角闪岩相区域热流变质作用改造，推测其形成于活动性较强大陆一大陆边缘环境。江绍断裂两侧早元古代变质基底在原岩建造、变质一变形作用等特征上存在明显差异，因此华夏地块和扬子地块在早元古代可能是两个地块。 相似文献
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华北地台含矽线石、蓝晶石的变质建造，主要由斜长角闪岩类、麻粒岩类、片麻岩类、含矿岩类和大理岩类组成。矽线石、蓝晶石矿床的变质作用已达到角闪岩相一麻粒岩相，各变质相的温压条件对矿床起着控制作用。 相似文献
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大别山产出的榴辉岩相岩石包括石榴橄榄岩、榴辉岩、榴云片岩、榴辉片麻岩、榴玉英岩和榴辉大理岩等不同系列,它们均分布于花岗质片麻岩中。矿物共生序列研究表明,榴辉岩相岩石经历了从绿帘角闪岩相、柯石英榴辉岩相、角闪榴辉岩相、绿帘角闪岩相到绿片岩相的演化过程。花岗质片麻岩及变质火山—沉积岩系并未经历超高压变质作用,但却与榴辉岩相岩石经历了同一期绿帘角闪岩相变质事件,证明二者在地壳范围内发生了构造合并 相似文献
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琉璃庙地区变质杂岩主要由变质上壳岩、变质深成侵入杂岩及其脉岩群组成.它们多数经韧性变形改造形成各种类型糜棱岩和构造片岩.研究表明,变质上壳岩原岩主要以钙碱性火山(熔)岩为主.本区变质杂岩经历了三期变质变形作用,即高角闪岩相区域变质作用形成大型复式同斜紧闭褶皱;绿帘角闪岩相动力变质作用及强烈的韧性变形,形成了以蓝闪石为特征的不同强度的糜棱岩带;绿片岩相动力变质作用和韧脆性变形作用. 相似文献
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新疆哈密东盐池附近变质基底属于塔里木板块北缘北山古生代裂谷带西段一部分,而板块北缘的北山地区古生代进入了陆块裂解、陆内裂谷发展演化时期。笔者对东盐池附近的变质岩进行了研究,将该区域变质作用分为区域变质、动力变质及接触变质等3个类型;将区内变质相分为低角闪岩相、高绿片岩相、低绿片岩相及葡萄石—绿纤石相等4个变质相带相系。研究了地质事件与变质变形的演化趋势,即变质作用从区域中高温变质、区域低温动力变质到区域埋深变质,变质作用的温度和压力随时代更新逐次降低。探讨了变质作用与矿产的关系,即变质作用控制变质矿产的分布。各种变质作用所形成的热液与其他热液一起促使成矿物质的活化迁移至有利部位成矿,形成了黑色岩系中的磷矿、石墨矿和钒矿等。 相似文献
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相山火山塌陷盆地基底变质岩U的地球化学研究 总被引：7，自引：0，他引：7
本文对相山火山塌陷盆地基底变质岩U的丰度及赋存形式进行了研究。基底变质岩中U主要以分散吸附状态的非结构U存在于基质或矿物粒间,少量的U以微粒、超微粒的独立铀矿物形式存在于矿物的裂隙中或粒间。U－Pb同位素的研究表明变质岩中的U在变质作用及后期的其它地质作用中发生了重新分配,并有不同程度的丢失,原始U含量较高。火山岩与变质岩的地球化学特征有许多相似之处。因此,作者认为基底变质岩有可能为成矿提供U源。 相似文献
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D. A. BREW G. R. HIMMELBERG R. A. LONEY A. B. FORD 《Journal of Metamorphic Geology》1992,10(3):465-482
The Cordilleran orogen in south-eastern Alaska includes 14 distinct metamorphic belts that make up three major metamorphic complexes, from east to west: the Coast plutonic–metamorphic complex in the Coast Mountains; the Glacier Bay–Chichagof plutonic–metamorphic complex in the central part of the Alexander Archipelago; and the Chugach plutonic–metamorphic complex in the northern outer islands. Each of these complexes is related to a major subduction event. The metamorphic history of the Coast plutonic–metamorphic complex is lengthy and is related to the Late Cretaceous collision of the Alexander and Wrangellia terranes and the Gravina overlap assemblage to the west against the Stikine terrane to the east. The metamorphic history of the Glacier Bay–Chichagof plutonic–metamorphic complex is relatively simple and is related to the roots of a Late Jurassic to late Early Cretaceous island arc. The metamorphic history of the Chugach plutonic–metamorphic complex is complicated and developed during and after the Late Cretaceous collision of the Chugach terrane with the Wrangellia and Alexander terranes. The Coast plutonic–metamorphic complex records both dynamothermal and regional contact metamorphic events related to widespread plutonism within several juxtaposed terranes. Widespread moderate-P/T dynamothermal metamorphism affected most of this complex during the early Late Cretaceous, and local high-P/T metamorphism affected some parts during the middle Late Cretaceous. These events were contemporaneous with low- to moderate-P, high-T metamorphism elsewhere in the complex. Finally, widespread high-P–T conditions affected most of the western part of the complex in a culminating late Late Cretaceous event. The eastern part of the complex contains an older, pre-Late Triassic metamorphic belt that has been locally overprinted by a widespread middle Tertiary thermal event. The Glacier Bay–Chichagof plutonic–metamorphic complex records dominantly regional contact-metamorphic events that affected rocks of the Alexander and Wrangellia terranes. Widespread low-P, high-T assemblages occur adjacent to regionally extensive foliated granitic, dioritic and gabbroic rocks. Two closely related plutonic events are recognized, one of Late Jurassic age and another of late Early and early Late Cretaceous age; the associated metamorphic events are indistinguishable. A small Late Devonian or Early Mississippian dynamothermal belt occurs just north-east of the complex. Two older low-grade regional metamorphic belts on strike with the complex to the south are related to a Cambrian to Ordovician orogeny and to a widespread Middle Silurian to Early Devonian orogeny. The Chugach plutonic–metamorphic complex records a widespread late Late Cretaceous low- to medium/high-P, moderate- T metamorphic event and a local transitional or superposed early Tertiary low-P, high-T regional metamorphic event associated with mesozonal granitic intrusions that affected regionally deformed and metamorphosed rocks of the Chugach terrane. The Chugach complex also includes a post-Late Triassic to pre-Late Jurassic belt with uncertain relations to the younger belts. 相似文献
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《China Geology》2018,1(1):137-157
The development of metamorphic petrology to metamorphic geology in China has a long history. Ancient basement metamorphic rocks are distributed primarily in the North China Craton, the Yangtze Block and Tarim Craton. They are mainly made up of plutonic gneiss and metamorphosed supercrust rock, transformed to granulite facies through Archean Paleoproterozoic. Many of the Paleoproterozoic metamorphic rocks have undergone high-pressure granulite facies metamorphism with a clockwise metamorphic evolution path. The ultrahigh temperature (UHT) granulites from the Late Paleoproterozoic are found in North China Craton. Many high-precision chronological data have allowed preliminary construction of the formation and evolutionary framework of different metamorphic basements. Primarily there are low-temperature and high-pressure blue schist, high-temperature and high-pressure granulite and ultrahigh-pressure (UHP) eclogite facies metamorphic rocks in the Phanerozoic orogenic belt. The discovery of eclogite in the Sulu orogen and a large quantity of coesite in its country rocks show that there was a deep subduction of voluminous continental materials during the collision process between the Yangtze block and the North China Craton in the Early Mesozoic phase. From the studies of, for instance, organic matter vitrinite reflectance, illite crystallinity, illite (muscovite) polytype and illite (muscovite) b dimension, the Late Paleozoic strata in the eastern region of Inner Mongolia and the north-central region of NE China have only experienced diagenesis to an extremely low-grade metamorphism. The discovery of impact-metamorphosed rocks in Xiuyan area of Liaoning province has enriched the type and category of metamorphic rocks in China. The phase equilibrium method has been widely used in the study of metamorphism of middle and high-grade metamorphic rocks. On the basis of existing geologic surveys and monographic study results, different scholars have respectively compiled 1:1500000 Metamorphic Geological Map and Specifications of Qinghai Tibet Plateau and its Adjacent Areas, 1:2500000 Metamorphic Tectonic Map of China, and the 1:5000000 Metamorphic Geological Map and Specifications of China, among others repectively, which have systematically summarized the research results of metamorphic petrology and metamorphic geology in China. 相似文献
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我国前寒武纪非金属矿产的分布及其特征 总被引：1，自引：0，他引：1
本文总结了我国前寒武纪非金属矿产的分布和特征,指出菱镁矿、硼矿、磷矿、滑石、石墨等非金属矿产赋存于不同的沉积建造、火山堆积以及不同变质岩系之中,是由古陆块的构造部位所决定的。前寒武纪非金属矿床的成矿作用与大陆地壳演化关系密切,古元古代大陆拼合焊接的造山带和新元古代稳定地块的海相沉积是两个十分重要的非金属矿产成矿构造环境,前者在中国北方（如胶辽裂谷、佳木斯地块）形成菱镁矿、硼矿、滑石矿和石墨矿等矿床,后者在南方（如扬子陆块、苏鲁大别带）主要形成磷矿床。前寒武纪产出大型、超大型非金属矿床数十个,成因类型主要有沉积变质型、岩浆热液型和沉积（弱变质）型,文中着重对硼、石墨、菱镁矿、滑石、磷矿等五个主要矿种的资源分布及矿床地质特征作了叙述。 相似文献
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Discovery and Geological Significance of Neoproterozoic Metamorphic Granite in Jimo, Shandong Province, Eastern China 总被引：1，自引：1，他引：0
ZHU Decheng Lü Dawei SHEN Xiaoli YANG Qing LI Dandan REN Tianlong YANG Shipeng 《《地质学报》英文版》2016,90(6):2080-2096
During the 1:50000 regional geological survey in Jimo,east Shandong Province,Paleoproterozoic metamorphic supracrustal rocks and Neoproterozoic metamorphic plutonite were newly discovered. These rocks displayed inclusions which had occurred in the Mesozoic granite,and the main lithologies are schist,granulite,marble,and granitic gneiss. Geochemical analyses suggest that Neoproterozoic metamorphic plutonite are characterized by high-K,metaluminous to weakly peraluminous. They are enriched in LILE and depleted in HFSE,with moderately enrichment of LREE,weak fractionation of LREE from HREE and negative Eu anomalies. The surface age of plutonic rocks in the survey area is 770.2±2.4 Ma,representing the age of magma crystallization,which is agreement with the the Neoproterozoic magmatic event after Rodinia supercontinent in the northern margin of Southern China continental block. In addition,the age of sporadic distribution(298 Ma and 269 Ma) is mixed zircon age,representing the rocks experienced metamorphism in Indosinian period. According to the associated mineral assemblages,and the characteristic metamorphic minerals and temperature pressure conditions,four metamorphic facies were identified,including amphibolitic,epidote amphibolite,greenschist,and mid-high pressure greenschist. Analysis of tectonic setting suggests that granitic gneiss is formed in an extensional environment and was involved from the continental margin magmatic arc to intraplate environment. Jimo is distributed in the east of Zhuwu fault,and has the same Spatial distribution location with the Weihai uplift UHP metamorphic belt rocks. The metamorphic rocks in Jimo area have similar geochemical characteristics of elements,tectonic setting and retrograde metamorphism with that in the Sulu UHP metamorphic belt. Therefore,Zhuwu fault may be the boundary fault of Sulu UHP metamorphic belt. 相似文献
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新疆太古宙变质岩系岩石组合特征 总被引：1，自引：2，他引：1
新疆塔里木盆地周边发育前寒武纪变质岩系，其太古宙变质岩系分布在库鲁克塔格－星星峡及阿尔金山前。铁克力克可能有新太古代变质岩系的存在。库鲁克塔格地区太古代变质岩出露较全，由古－中太古代及新太古代变质岩组成：阿尔金山前、南天山及中天山尾亚地区均有新太古代变质岩系分布。太古代变质岩系由表壳岩和变质深成岩（岩系）组成，前者往往呈规模不等的包体散布在变质深成岩中。变质作用主要为区域中高温变质作用和区域动力热流变质作用，变质相为中深变质的角闪岩相－麻粒岩相，具中深部构造相的塑性流变特征。 相似文献
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123 mineral separates from 37 rock samples of the northern Ötztal-Stubai Alps have been analysed for their oxygen- and 38 minerals for their hydrogen isotopic composition. The results confirm that alpine metamorphism had little influence on the rocks of the crystalline basement. No large scale transport of water through the rocks of the crystalline basement occurred during the alpine event. The temperature of alpine metamorphism did not exceed 530 °C, whereas the temperature of the prealpine metamorphic events was higher than 600 °C. The high temperatures of prealpine metamorphism are preserved in some 18O/16O mineral fractionations (mainly quartz/ilmenite), even in rocks which have partially reequilibrated during alpine metamorphism. The overprinting of the alpine metamorphism on the rocks of the crystalline basement and of the Schneebergerzug is indicated by oxygen isotope disequilibria which results in a large scatter of oxygen isotope temperatures. The main metamorphism of the rocks of the Schneebergerzug has to be related to a prealpine event. Metamorphic textures of quartz indicate that recrystallization is the most important mechanism for the reequilibration of oxygen isotopes. 相似文献
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辽宁北镇地区新太古代变质深成岩是该地区最古老的结晶基底,各侵入岩体普遍发生变质变形,原岩结构构造发生改变.据岩体特征及分布划分为小牵马岭片麻杂岩、白厂门片麻岩两个岩石单位.小牵马岭片麻杂岩SiO2含量在59.69%~76.22%,液相线温度为720~1024℃,岩浆分异程度较高.白厂门片麻岩液相线温度为776~1024℃,岩浆分异指数DI值为68.99~91.68,分异值较高.白厂门片麻岩Ba/Sr比值与小牵马岭片麻杂岩比值接近,稀土配分曲线呈右倾,二者形态基本平行,说明这两种岩石物质来源相似,为铕异常明显的轻稀土富集型 相似文献