Proterozoic tectonic evolution and late Svecokarelian plate deformation of the Central Baltic Shield

The continental crust of the Central Baltic Shield evolved by accretion towards the west during the Svecokarelian orogeny 1700–2200 Ma ago. The following features are consistent with a plate tectonic mechanism involving subduction of oceanic crust below an Archean craton in the east: flysch-sediments with serpentinite masses and pillow lavas, linear high-grade metamorphic zones, island-arc type volcanic belts and late tectonic batholiths with porphyry type Cu-Mo deposits.Semi-consolidated new crust was affected by late Svecokarelian deformation (D_n) after 1850 Ma; NNE-trending folds with crenulation cleavage were overprinted on older structures together with associated NW trending ductile transcurrent shear zones that curve the F_n folds into gentle S and Z shapes. The late tectonic batholiths intruded partly at the same time as and partly after the D_n deformation.

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Zusammenfassung Die kontinentale Kruste des zentralen Baltischen Schildes entwickelte sich durch nach Westen gerichtetes Anwachsen während der Svecokarelischen Orogenese vor 1700 bis 2200 Ma. Die folgenden Erscheinungsformen lassen sich mit einem plattentektonischen Mechanismus in Einklang bringen, der Subduktion von ozeanischer Kruste unter einen Archaischen Kraton im Osten einschließt: Flysch-Sedimente mit Serpentinit-Massen und Kissenlaven, lineare hochmetamorphe Zonen, vulkanische Gürtel vom Inselbogen-Typ und spättektonische Batholithe mit porphyrischen Cu-Mo-Lagerstätten.Die halbkonsolidierte neue Kruste wurde durch späte Svecokarelische Deformation (D_n) nach 1850 Ma erfaßt; NNE-orientierte Falten mit Krenulationsschieferung wurden älteren Strukturen aufgeprägt in Verbindung mit NW-streichenden, plastischen Transcurrent-Scherzonen, die die F_n-Falten in sanfte S- und Z-Formen verbiegen. Die spättektonischen Batholithe intrudierten teils während, teils nach der D_n-Deformation.

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Résumé La croûte continentale du Boucher baltique central a évolué par voie d'accrétion vers l'ouest durant l'orogénie svécocarélienne 1700–2200 Ma. Les événements suivants sont en accord avec un mécanisme de tectonique de plaques impliquant la subduction d'une croûte océanique sous un craton archéen à l'est: sédiments flyschoïdes avec masses de serpentinite et de laves en coussins, zones linéaires à haut degré de métamorphisme, ceintures volcaniques du type guirlande d'îles et batholithes tectoniques tardifs avec gisements porphyriques de type Cu-Mo.La nouvelle croûte à semi-consolidée fut affectée par une déformation svécocarélienne tardive (D_n) postérieure à 1850 Ma. Des plis de direction NNE avec clivage de crénulation ont été superposés sur des structures plus anciennes, associés à des zones de cisaillement transcurrentes de direction NW qui ont incurvé les plis F_n suivant des formes en S et Z. Le batholithe tectonique tardif s'est mis en place en partie au même moment que, et en partie après, la déformation D_n.

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, , 1500–2200 . , , : ; ; - . , 1850 ; NNE- , , NW , , F_n S Z. , .

     

Proterozoic evolution and tectonic setting of the northwest Paterson Orogen,Western Australia

The Proterozoic igneous, deformation and metamorphic histories of the Palaeoproterozoic Rudall Complex in the northwestern Paterson Orogen can be linked to those of the Arunta Inlier in central Australia, and in part with the Capricorn Orogen in central Western Australia. The similarities in deformation and metamorphic histories for these widely separated regions indicate a Palaeoproterozoic continent–continent collisional event between the Palaeoproterozoic West Australian and North Australian cratons between c. 1830 and 1765 Ma. In the Paterson Orogen this Palaeoproterozoic collisional event resulted in the Yapungku Orogeny, which included thrust stacking of clastic sedimentary and volcanic rocks, deposition of the protoliths for the c. 1790 Ma siliciclastic paragneiss succession contemporaneous with granitic intrusion, and metamorphism up to granulite facies. During this 65-million-year period, the Arunta Inlier and Capricorn Orogen were deformed, metamorphosed at medium to high grades and intruded by granitoids during the Strangways Orogeny in the Arunta Inlier and the Capricorn Orogeny in the Capricorn Orogen.The Neoproterozoic Tarcunyah, Throssell and Lamil groups are clastic sedimentary sequences that were deposited after 1070 Ma in the northwestern Paterson Orogen, and deformed by the Miles Orogeny before 678 Ma. The Miles Orogeny produced a northwesterly trending fold and fault system of tight to isoclinal upright and overturned folds and thrust faults. The orogeny may have been coincident with the c. 750–720 Ma Areyonga tectonic movement affecting the Arunta Inlier and the lower Neoproterozoic part of the Amadeus Basin in central Australia. At c. 550 Ma the Paterson Orogeny, which is most likely equivalent to the Petermann Orogeny in the Musgrave Complex of central Australia, deformed the northwestern Paterson Orogen and was preceded by local intrusion of granites.The similarities of styles and timing of deformation in the northwestern Paterson Orogen, Arunta Inlier and Capricorn Orogen indicate that these three regions were probably linked during most of the Proterozoic.     

新疆北部大地构造演化阶段与斑岩－浅成低温热液矿床的构造环境类型

本文系统总结了新疆北部斑岩-浅成低温热液矿床的成矿时代,按构造环境将该类矿床归为三大类型:洋-陆俯冲型、碰撞造山型、板内型,其中碰撞造山型又可分为碰撞型和后碰撞型。4类矿床的差别主要在于矿床金属元素组合,以及同期相伴出现的矿床类型不同:俯冲型斑岩矿床以斑岩Cu-Au矿-浅成低温热液Au矿组合为主,以伴有海相火山岩有关的VMS矿床和铁矿为特征;碰撞型和后碰撞型矿床以斑岩Cu-Mo-Au组合为主,伴有构造蚀变岩型复合/叠加的浅成低温热液型Au矿出现;板内型矿床以斑岩型单Mo(或Mo-Re)组合为主。斑岩矿床与浅成低温热液矿床虽为同一成矿系统,但二者基本不共生,且后者成矿时代一般晚于前者10～20 Ma。斑岩-浅成低温热液矿床的含矿岩石和成矿特征并不随构造环境类型不同而出现特征性差别。不同时期的斑岩矿床在分布上具有继承性和"同位成矿"特点,并表现出一定的分带性,从早到晚逐渐由靠近缝合带向外扩展、由线型分布逐渐趋于面型分布。     

Foreword: Magma generation and evolution in the Earth

A VOLUME IN HONOUR OF THE WORK OF MICHAEL J. O'HARA, ON THE OCCASION OF HIS 70TH BIRTHDAY The 20th century was eventful inall areas of Earth Science. Continental drift and sea-floorspreading became embodied in the theory of plate tectonics,isotopically heterogeneous mantle was recognized as a by-productof plate tectonics, large igneous provinces were identifiedas possibly originating from mantle plumes - the list goes on.One thing these revolutions have in common is the process ofscientific debate - which Mike O'Hara has stimulated vigorouslyin the field of     

Supercontinent evolution and the Proterozoic metallogeny of South America

The cratonic blocks of South America have been accreted from 2.2 to 1.9 Ga, and all of these blocks have been previously involved in the assembly and breakup of the Paleoproterozoic Atlantica, the Mesoproterozoic to Neoproterozoic Rodinia, and the Neoproterozoic to Phanerozoic West Gondwana continents. Several mineralization phases have sequentially taken place during Atlantica evolution, involving Au, U, Cr, W, and Sn. During Rodinia assembly and breakup and Gondwana formation, the crust-dominated metallogenic processes have been overriding, responsible for several mineral deposits, including Au, Pd, Sn, Ni, Cu, Zn, Mn, Fe, Pb, U, P₂O₅, Ta, W, Li, Be and precious stones. During Rodinia breakup, epicontinental carbonate-siliciclastic basins were deposited, which host important non-ferrous base metal deposits of Cu–Co and Pb–Zn–Ag in Africa and South America. Isotope Pb–Pb analyses of sulfides from the non-ferrous deposits unambiguously indicate an upper crustal source for the metals. A genetic model for these deposits involves extensional faults driving the circulation of hydrothermal mineralizing fluids from the Archean/Paleoproterozoic basement to the Neoproterozoic sedimentary cover. These relations demonstrate the individuality of metal associations of every sediment-hosted Neoproterozoic base-metal deposit of West Gondwana has been highly influenced by the mineralogical and chemical composition of the underlying igneous and metaigneous rocks.     

Petrology, geochemistry and tectonic settings of the mafic dikes and sills associated with the evolution of the Proterozoic Cuddapah Basin of south India

In this article we summarize the petrological, geochemical and tectonic processes involved in the evolution of the Proterozoic intracratonic Cuddapah basin. We use new and available ages of Cuddapah igneous rocks, together with field, stratigraphic, geophysical and other criteria, to arrive at a plausible model for the timing of these processes during basin evolution. We present petrological and geochronological evidence of dike emplacement along preferred lineament directions around the basin in response to stresses, which may have been responsible for the evolution of the basin itself. Basaltic dike intrusion started on the south Indian shield around 2400 Ma and continued throughout the Cuddapah basin evolution and sedimentation. A deep mantle perturbation, currently manifested by a lopolithic cupola-like intrusion under the southwestern part of the basin, may have occurred at the onset of basin evolution and played an important role in its development. Paleomagnetic, gravity and geochronological evidence indicates that it was a constant thermal source responsible for dike and sill emplacement between 1500 and 1200 Ma both inside and out-side the basin. Lineament reactivation in the NW-SE and NE-SW directions, in response to the mantle perturbation, intensified between 1400 and 1200 Ma, leading to the emplacement of several cross cutting dikes. Fe-Mg partition coefficients of olivine and augite and Ca-Na partition coefficient of plagioclase, calculated from the composition of these minerals and bulk composition of their host rocks, indicate that the dikes outside the Cuddapah basin are cumulates. The contemporary dikes may be related by fractional crystallization as indicated by a positive correlation between their plagioclase Ca# (atomic Ca/[Ca+Na]) and augite Mg# (atomic Mg/[Mg+Fe]). A few NW-SE and NE-SW cross cutting dikes of the period between 1400 and 1200 Ma, preserve petrographic evidence of episodic magmatic intrusive activity along preferred directions. Petrological reasoning indicates that a magmatic liquid reacted with a set of cross cutting dikes, intruding into one that was already solidified and altering the composition of the magma that produced the other dike. The Cuddapah basin tholeiites may be related by fractional crystallization at 5 kb and 1019-1154‡ C, which occurred in the lopolithic cupola near the southwestern margin of the basin. Xenolith bearing picrites, which occur near the periphery of the cupola, originated by the accumulation of xenoliths in the tholeiites. This is indicated by the composition of the olivine in the xenoliths (Fo_78.7-81.9), which are closely similar to calculated olivine compositions (Fo_77.8-78.3) in equilibrium with the tholeiites under the sameP-T conditions. It is inferred that fractionation in the cupola resulted in crystals settling on its walls. Hence, the xenolith-bearing sills occur at the periphery of the lopolithic body. The tholeiites both inside and outside the basin are enriched in incompatible elements compared to mid oceanic ridge basalts. The Ba, Rb and K contents of the Cuddapah and other Proterozoic Gondwana tholeiites indicate that a widespread metasomatic enrichment of the mantle source may have occurred between R∼2.9 and R∼2.7Ga. There may be local heterogeneity in the source of the Cuddapah tholeiites as indicated by different Ba/Rb, Ti/Zr, Ti/Y, Zr/Nb and Y/Nb in samples inside and outside the basin. Large-scale differences such as the low P₂O₅-TiO₂ and high P₂O₅-TiO₂ basaltic domains of the Jurassic Gondwana basalts, however, did not exist during the Proterozoic time period under consideration. Although we are beginning to understand the tectono-magmatic processes involved in the evolution of the Cuddapah basin, much work remains to be done to obtain a complete picture. Future research in the Cuddapah basin should focus on obtaining accurate ages of the igneous rocks associated with the evolution of the basin.     

赣东北地区中晚元古代的岩浆作用与构造环境

通过调研认为赣东北地区中晚元古代岩浆岩包括:蓟县纪-青白口纪早期的斜长花岗岩、蛇绿岩套、拉斑玄武岩、钙碱性火山岩、强过铝花岗岩;青白口纪晚期的双峰式火山岩、岩浆混合岩、钾玄岩和基性岩墙;南华纪的碱长花岗岩和地幔岩等.它们分别是与B型俯冲作用有关的弧盆系、与造山后伸展的的裂谷系及非造山大地构造环境中产生岩浆岩组合,显示该区在蓟县纪-青白口纪早期发生两次B型俯冲作用和青白口纪晚期的大规模裂陷以及南华纪造山活动的已趋稳定.中晚元古代是一个分期明显、岩类完整、演化连续的造山旋回.     

深切怀念王鸿祯院士

再过一些时间就是王鸿祯院士的百年诞辰,此时此刻,更令我对他深深怀念。在他离去的这些年当中,每当我看到有关的书籍、文献,就会想到他老人家;他的学术思想、治学态度和奋斗精神,更时时激励我前进。在王鸿祯院士生前,我有时是当面请教得到指导,更多是通过学习他的著述而收益。 20世纪50年代初,我有几位同学在新建的北京地质学院研究生班学习,他们谈起校内教授中的“少壮派”--在国外获得博士学位,年纪30多岁,执掌教研室和系主任岗位,个个风华正茂,其中就有王鸿祯教授。但我第一次见到王先生是在1955年,那年夏季,苏联科学院代表团访华,代表团成员、著名大地构造学家别洛乌索夫通讯院士在我所（当时位于城内沙滩松公府夹道、原北京大学地质馆的中国科学院地质研究所）做包括苏联大地构造、中国大地构造的有关问题以及大洋盆地的成因等系列报告。王鸿祯先生参加了有关会议,他提出问题发表讨论意见,我当时负责会议记录和部分接待工作,有幸第一次近距离地同他有过接触,他和蔼可亲,时间虽短但留下了长期的印象。 1956年,王鸿祯先生著的《地史学教程》出版,我很快购得一本并开始学习。一天,叶连俊先生在办公室里见我手里拿着这本书,说道：“这（地史学）同我们的沉积学关系也很大”,我说：“我的基础知识不够,许多内容不懂”,叶先生说：“慢慢来,先掌握一点基本概念”。这是叶先生对我学习《地史学教程》的指导。王先生的《地史学教程》使我初步开阔了对世界地质在空间和时间上的视野。受此书的影响,我形成了一个习惯,尽管有许多地质问题,我自己并不直接研究,但愿意去了解,从中获取知识的享受。 1985年,王鸿祯先生主编的《中国古地理图集》出版,受到学术界的广泛注意和高度评价。图集以全球构造的活动论与历史发展的阶段论有机结合作为主导原则,代表王鸿祯先生学术思想发展的新阶段。图集内容十分丰富,我曾较为仔细地阅读了差不多每一幅图件并认真阅读了图集说明书,还读了图集的英文说明,以便了解图集的有些名词术语同国外文献的对照和衔接。我后来也曾向王先生请教过一些问题,如今还记得的有：豫陕（图集引用了我的文章）和燕辽裂陷盆地（拗拉槽）、俄罗斯地台的拗拉槽、扬子地台有无拗拉槽,以及拗拉槽是否都是三支裂谷系的废弃支等等,他同我也谈到朱夏先生将aulacogen译作“拗拉槽”可称杰作。王先生还向我指出国内需要重视古大陆的重建问题,这是国际关注的热点,但意见分歧很大,我国应该有更多些学者进入这一领域进行探讨。王先生的一系列意见对我真可谓受益匪浅。 1989年在华盛顿参加国际地质大会期间,在国际岩石圈计划的会上,我遇到美国的Scotese教授,他当时已着手“古地图”（PaleoMap）项目并送给我一点有关资料,Scotese在会上强调编制古地图的三个支柱是板块构造、古地磁和古生物地理。回国后我向王先生汇报了有关情况,王先生也特别强调古生物地理对古地理重建的重要性。据我所知,在王鸿祯先生的率领下,中国地质大学在20世纪80年代后期,已经开展全球构造与古大陆再建研究,采用计算机成图并开发了有关软件。在1996年国际地质大会（北京）上,展出了古大陆再造的系列图件,这在当时是国内学者首次作出这样的努力。就中国地质大学而言,王鸿祯先生和殷鸿福教授等都曾在古生物地理方面做出许多贡献。 20世纪90年代初,原国家科委推出了以“攀登计划”为名的基础研究资助计划。有个年度我担任地学与资源环境领域的评审组长,那一回总共约有6、7项申请,王鸿祯先生领衔的中国古大陆及边缘层序地层与海平面变化研究的申请,在经过讨论后,投票排名第二。当时国家科委只限定资助一项,我和评审专家组其他专家都认为王先生的建议项目有价值,是值得资助的,但投票结果也是公正和正确的。因此,我们决定向科委建议,给我们组增加一个项目指标,科委有关负责人听取了我的意见,但一时也无变通的余地。过了一段时间,国家科委又推出“攀登计划B”,层序地层学项目可以入选,但需承担项目的主管部门提供部分联合资助。我把这个情况转告王鸿祯先生,王先生当时已年近八旬,他亲自同地质矿产部科学技术司沟通,终于获得成功。王先生已80高龄,亲自领导了由若干单位几十位专家组成的团队,经过四五年的浩繁研究工作,获得了圆满的成功。我有幸数年中应邀参加了该项目的学术研讨会,分享王鸿祯先生的学术思想和项目在学术上的新进展。 在科学研究中,王鸿祯先生重视基础研究,可以说他的一生都在追求揭示自然的奥秘,开展创新性研究。我在国家自然科学基金委员会和中国科学院地学部工作期间,向他请教学科发展战略问题等,他都强调基础研究的重要性,强调基础学科的发展。事实证明,基础研究在我国科学技术事业的发展中,具有根本的重要性。王先生为我国地质科学的基础研究贡献了毕生的精力。 王鸿祯院士是国内外著名的地质学家、古生物学家和地质教育家。在地层学、古生物学、大地构造学、地史学和地质学史研究等诸多领域成就卓著,在发展地质教育和培养人才方面作出重要贡献。王鸿祯先生青少年时代就胸怀“科学救国”之志,勤奋学习,砥砺意志,殚思竭虑发展教育事业,孜孜不倦献身科学研究,学科综合交叉和继承发展创新贯穿他的毕生学术生涯。王鸿祯院士是我国地质界著名宗师之一,在纪念他诞辰100周年之际,我应当继续不断学习他对地质科学和地质教育的献身精神。他的大量文章著作和重要学术思想是留给我们的宝贵财富,必将得到继承发展并不断发扬光大。     

地壳不同构造层次岩石变形机制及其构造岩类型

构造岩记录地壳构造变形演化重要信息,其成因、分类与命名一直没有统一认识。本文对构造岩变形机制、控制因素和构造岩分类进行系统总结。认为构造岩形成受物质成分、变形机制、应变速率、流体、温度、压力等因素控制,是物质成分与物理化学条件、变形机制等众多变量的函数。变形机制包括破裂作用、碎裂流动、晶质塑性、物质扩散、重结晶作用和超塑性流动,不同变形机制出现在不同地壳构造层次中,形成不同的显微组构。依据成因机制、物质组成和组构等标志对构造岩分类与命名进行重新修订,将构造岩划分为碎裂岩系列和变质构造岩系列,前者发育在地壳浅构造层次上,以破裂作用和碎裂流动变形机制为主;后者发育在中深部构造层次上,以晶质塑性、重结晶作用、物质扩散作用和超塑性流动作用为主。碎裂岩系列划分碎裂岩、角砾岩、微角砾岩、超碎裂岩、断层泥和假玄武玻璃;变质构造岩系列划分为构造片岩、糜棱岩和构造片麻岩。依据岩石流变性质、变形机制和构造岩分布,地壳构造层次划分为：脆性域,变形机制以碎裂作用和碎裂流动为主,发育碎裂岩系列;脆-韧性转换域,以晶质塑性、物质扩散和重结晶作用为主,并伴随有碎裂作用,形成糜棱岩、千糜岩和构造片岩;低温韧性域,以晶质塑性、物质扩散和重结晶作为主,发育糜棱岩与构造片岩;高温韧性域,以超塑性蠕变和重结晶作用为主,形成构造片麻岩。

     

贺兰山构造带构造—地层层序及构造演化

贺兰山构造带及邻区形成演化经历有多期叠加改造和多个伸展—聚敛旋回构造运动,形成了区域内多套构造—地层层序,因此,开展贺兰山构造带构造—地层层序及构造演化研究对深入理解其地质结构和油气勘探有着重要的意义。本文旨在综合利用野外调查、地震数据和1：50 000区域地质资料,采用野外实地调查和地震剖面精细解析相结合的方法对研究区区域不整合面的分布特征和规律进行详尽分析研究,根据区域不整合面的发育特征,建立区域地层年代格架,划分构造—地层层序,进而对盆地演化阶段进行探讨。研究表明,研究区自下至上发育Pt2Ch-Jx/Pt1、∈1/An ∈、C2/O、T/P、J1-2/An J、K1/An K1、E3q—N/AnE,据此将研究区垂向上划为7个构造—地层层序：基底构造层、中元古界构造层、震旦系—奥陶系构造层、石炭系—三叠系构造层、侏罗系构造层、下白垩统构造层、新生界构造层。贺兰山构造带构造演化经历中新元古代—早古生代陆缘盆地坳陷—裂谷演化阶段;晚古生代—中三叠世陆相盆地坳陷沉积阶段;晚三叠世局部伸展;中侏罗世—早白垩世大规模逆冲推覆阶段,普遍发育多条大型北东向逆冲断裂;始新世开始进入盆—岭构造形成阶段。     

贺兰山构造带构造—地层层序及构造演化

贺兰山构造带及邻区形成演化经历有多期叠加改造和多个伸展—聚敛旋回构造运动,形成了区域内多套构造—地层层序,因此,开展贺兰山构造带构造—地层层序及构造演化研究对深入理解其地质结构和油气勘探有着重要的意义。本文旨在综合利用野外调查、地震数据和1：50 000区域地质资料,采用野外实地调查和地震剖面精细解析相结合的方法对研究区区域不整合面的分布特征和规律进行详尽分析研究,根据区域不整合面的发育特征,建立区域地层年代格架,划分构造—地层层序,进而对盆地演化阶段进行探讨。研究表明,研究区自下至上发育Pt₂Ch-Jx/Pt₁、∈₁/An∈、C₂/O、T/P、J_1-2/An J、K₁/An K₁、E₃q—N/AnE,据此将研究区垂向上划为7个构造—地层层序：基底构造层、中元古界构造层、震旦系—奥陶系构造层、石炭系—三叠系构造层、侏罗系构造层、下白垩统构造层、新生界构造层。贺兰山构造带构造演化经历中新元古代—早古生代陆缘盆地坳陷—裂谷演化阶段;晚古生代—中三叠世陆相盆地坳陷沉积阶段;晚三叠世局部伸展;中侏罗世—早白垩世大规模逆冲推覆阶段,普遍发育多条大型北东向逆冲断裂;始新世开始进入盆—岭构造形成阶段。     

Concerning tectonics and the tectonic evolution of the Arctic

The particularities of the current tectonic structure of the Russian part of the Arctic region are discussed with the division into the Barents–Kara and Laptev–Chukchi continental margins. We demonstrate new geological data for the key structures of the Arctic, which are analyzed with consideration of new geophysical data (gravitational and magnetic), including first seismic tomography models for the Arctic. Special attention is given to the New Siberian Islands block, which includes the De Long Islands, where field work took place in 2011. Based on the analysis of the tectonic structure of key units, of new geological and geophysical information and our paleomagnetic data for these units, we considered a series of paleogeodynamic reconstructions for the arctic structures from Late Precambrian to Late Paleozoic. This paper develops the ideas of L.P. Zonenshain and L.M. Natapov on the Precambrian Arctida paleocontinent. We consider its evolution during the Late Precambrian and the entire Paleozoic and conclude that the blocks that parted in the Late Precambrian (Svalbard, Kara, New Siberian, etc.) formed a Late Paleozoic subcontinent, Arctida II, which again “sutured” the continental masses of Laurentia, Siberia, and Baltica, this time, within Pangea.     

The tectonic evolution of Australia

Fifteen non-palinspastic palaeotectonic maps, and accompanying explanatory text, are presented to illustrate the progressive development of the Australian continental block from the Archaean to the present. They summarise the structural and chronological framework of tectonic events in Australia as a data base for further research. They are a development from the Tectonic Map of Australia and New Guinea (GSA, 1971).Areas on the maps are classified into Precratonic (Orogenic), Transitional, and Cratonic Domains, and these are further subdivided into various subunits. Areas of known outcrop are distinguished from concealed or inferred rocks.Australia and New Guinea may be divided into major crustal blocks, each of which has its own history and tectonic style, and each of which represents an important stage in the evolution of the Australian continent. Although significant differences are shown between the tectonic patterns developed during the Proterozoic and the Phanerozoic, even more significant parallels exist: the same scheme of tectonic analysis and classification may be applied to both. The fundamental tectonic cycle of geosynclinal deposition and orogenesis, through transitional tectonism, to cratonisation and platform cover deposition, is evident throughout.     

赣南早元古代中深变质岩地层时代及构造意义

发育在赣南地区的寻乌岩群,为一套中深变质岩系,前人归属寒武纪.在1∶ 5万小江图组区调工作中,通过岩石地层、变质变形构造特征及侵位于其中的片麻状花岗岩同位素年代地质学研究,将其时代重新厘定为古元古代.这一认识为探讨华夏古陆结晶基底及华南大地构造演化提供了新的资料.     

Tectonic progradation and plate tectonic evolution of the Alps

Rifting and spreading, trench formation, flysch deposition, subduction and nappe formation prograde from internal to external parts of the Alpine orogen. The progradation is a characteristic feature of the evolution of the Alps. A plate tectonics model based on this cognition is presented and an attempt is made to integrate the plate movements of the Alpine region during the Mesozoic and Cenozoic into the plate pattern of the Western Mediterranean.

Important events in the evolution of the Alps are the successive opening and closing of the Piedmont (South Penninic) and Valais (North Penninic) oceans, and the two continental collisions related to this. The southward drift of the Briançonian plate in the Cretaceous closes the Piedmont and opens the Valais ocean. The evolution of these oceans is related to the plate movements in the North Atlantic. The second continental collision is followed by the formation of an exogeosyncline, the molasse foredeep.

Prograding orogens like the Alps are most likely to evolve in an originally continental environment by rifting. Retrograding orogens, however, indicate an originally oceanic environment with well-developed magmatic arcs and back-arc basins.     

Cenozoic volcanism and tectonic evolution of the Tibetan plateau

Cenozoic volcanism on the Tibetan plateau, which shows systematic variations in space and time, is the volcanic response to the India–Asia continental collision. The volcanism gradually changed from Na-rich + K-rich to potassic–ultrapotassic + adakitic compositions along with the India–Asia collision shifting from contact-collision (i.e. “soft collision” or “syn-collision”) to all-sided collision (i.e. “hard collision”). The sodium-rich and potasium-rich lavas with ages of 65–40 Ma distribute mainly in the Lhasa terrane of southern Tibet and subordinately in the Qiangtang terrane of central Tibet. The widespread potassic–ultrapotassic lavas and subordinate adakites were generated from ~ 45 to 26 Ma in the Qiangtang terrane of central Tibet. Subsequent post-collisional volcanism migrated southwards, producing ultrapotassic and adakitic lavas coevally between ~ 26 and 8 Ma in the Lhasa terrane. Then potassic and minor adakitic volcanism was renewed to the north and has become extensive and semicontinuous since ~ 20 Ma in the western Qiangtang and Songpan–Ganze terranes. Such spatial–temporal variations provide important constraints on the geodynamic processes that evolved at depth to form the Tibetan plateau. These processes involve roll-back and break-off of the subducted Neo-Tethyan slab followed by removal of the thickened Lhasa lithospheric root, and consequently northward underthrusting of the Indian lithosphere. The Tibetan plateau is suggested to have risen diachronously from south to north. Whereas the southern part of the plateau may have been created and maintained since the late-Oligocene, the northern plateau would have not attained its present-day elevation and size until the mid-Miocene when the lower part of the western Qiangtang and Songpan–Ganze lithospheres began to founder and detach owing to the persistently northward push of the underthrust Indian lithosphere.     

Reconciliation of conflicting tectonic models for Proterozoic rocks of northern New Mexico

Two major Proterozoic tectonic events are documented in the Taos Range of northern New Mexico. Regional structures involving the tectonic interleaving of c.   1.65  Ga granitoids with supracrustal rocks are interpreted to have formed before 1.42  Ga and probably during collisional assembly of island arc crust into new (1.7–1.6  Ga) continental lithosphere. Supracrustal rocks record 650–750  °C, 6–8  kbar metamorphism (M₂); these high temperatures may have been reached during sandwiching between c.   1.65  Ga granitoids. However, the early history has been obscured by renewed tectonism at c.   1.4  Ga that resulted in partial melting, fabric reactivation and new mineral growth at 4  kbar (M₃). Metamorphic temperature variations from uppermost-amphibolite to amphibolite facies rocks may be associated with c.   1.65 and/or 1.4  Ga plutonism, but not to a 1.4  Ga extensional shear zone as previously proposed. Syn- and post-1.4  Ga contraction is suggested by high- and low-temperature microstructures showing top-to-the-south-east thrusting. This work reconciles conflicting models by suggesting that the geometry of the structures was mainly established by c.   1.65  Ga, but that the present fabric also records 1.4  Ga tectonism involving high- T  metamorphism and fabric reactivation.     

北山造山带大地构造相及构造演化

根据1:25万马鬃山幅区调填图资料,从造山带不同构造单元的火山-沉积建造、岩浆岩序列演化、变质变形特征及时空配位关系研究入手,应用大地构造相划分理论,根据北山多旋回复合造山带的特点,识别出15种大地构造相,并探讨了北山古生代构造格局与构造演化模式.     

黔中隆起性质及其构造演化

"黔中隆起"是雏形于晚寒武世郁南运动的东西向平缓隆起,经历了都匀运动水下隆起向陆上隆起的转化发展阶段。通过对比沉积岩相与古地理研究,黔中隆起水陆转换开始于晚奥陶世涧草沟期,即都匀运动发生的时间,鼎盛时期发育在晚奥陶世五峰期至早志留世龙马溪期。广西运动期间,受到来自南部云开地块与桂滇-北越地块的挤压和南东向华夏地块与扬子板块汇聚、碰撞脉动式收缩的远程效应,出现了以黔中背斜、乌当-二比向斜为代表的东西向构造带和以麻江背斜为代表的南北向构造带共存的现象,之后,"黔中隆起"作为独立意义的构造单元消失,与"江南古陆"相连接进入联合发展时期。东吴运动和峨眉山玄武岩的喷发改变了黔中隆起控制东西走向的沉积古地理格架,变为近南北向,黔中隆起与上扬子地区的构造演化彻底融为一体,标志黔中隆起演化的彻底结束。黔中隆起南缘边界的镇远—贵阳断裂中的钾镁煌斑岩单颗粒锆石U-Pb同位素年龄为(261.3±8.0)Ma,很好地指示了黔中隆起作为独立单元发展的最后年限。     

西南极岩浆作用及构造演化

西南极主要由哈格冰原岛峰群、南极半岛、瑟斯顿岛、玛丽·伯德地和埃尔斯沃思-惠特莫尔山脉五个各具特色的地壳块体组成。通过综述上述各块体主要的岩浆事件及其构造意义,旨在了解西南极的地质演化过程。西南极最古老的岩石为哈格冰原岛峰群地块的前寒武纪正片麻岩,时代为1238 Ma,记录了中元古代弧岩浆作用,其余四个地块记录了~500 Ma以来的地质演化过程。古生代时期,埃尔斯沃思-惠特莫尔山脉地块处于快速沉降的陆相断陷盆地环境,岩浆活动稀少,与罗斯造山运动形成的弧后伸展有关;玛丽·伯德地地块中—晚古生代发育一套与板块汇聚有关的岩浆作用,形成于活动大陆边缘环境;而南极半岛-瑟斯顿岛地块记录了石炭纪—二叠纪时期弧的发育。各地块的构造背景从侏罗纪开始明显分化,埃尔斯沃思-惠特莫尔山脉地块记录了侏罗纪板内岩浆作用,可能与大火成岩省有关;玛丽·伯德地地块发育的侏罗纪—早白垩世Ⅰ型弧岩浆岩随时间转变为白垩纪中期的A型碱性岩浆岩,经历了由俯冲向裂解机制的转变;南极半岛-瑟斯顿岛地块侏罗纪—白垩纪为弧岩浆活动活跃期,同时也有大火成岩省火山活动的记录,是持续俯冲和裂解相互作用的产物。新生代岩浆作用以南极半岛地块为代表,弧岩浆作用持续到始新世,其时空分布特征与左行错断扩张脊的分段俯冲和碰撞有关。