Tectonotype of nonvolcanic passive margins in the Iberia-Newfoundland region

The tectonotype of nonvolcanic passive margins is discussed on the basis of data on the conjugate margins of West Iberia and Newfoundland. Magmatic, structural, and historical aspects are considered. The Late Mesozoic structural elements related to rifting and transition to spreading are considered, as well as the Early Mesozoic sedimentary basins that begin the history of oceanic opening. The problem is set to determine the tectonic conditions of the early opening of the ocean in the framework of the chosen tectonoptype. These conditions are compared with the setting at the volcanic margins. The formation of the conjugate Iberia-Newfoundland margins is reconstructed as an asymmetric rift system developing in an almost amagmatic regime. All three segments of the margins on both sides of the ocean reveal similar features of transverse zoning with zones of the tectonized continental, transitional, and oceanic crust oriented nearly parallel to the margin. Special attention is called to the old age of the continental crust and subcontinental mantle and the absence of newly formed crystalline crust; the stadial tectonic and rheological evolution of the crust and lithospheric mantle; the specific features of the transitional zone; the serpentinization and exhumation of mantle peridotites and their role in the development of detachment at the crust-mantle interface, related listric faults and the Peridotite Ridge, attenuation of the medium, further localization of continental breakup, and the eventual development of asymmetric conjugate margins. Two papers characterizing the tectonotypes of volcanic and nonvolcanic passive margins ([2] and this paper) determine the line of further comparative analysis necessary for insights into the geodynamics of ocean opening.     

Evolution of sedimentary basins from Mesozoic times in Australia's continental slope and shelf

Three basic tectonic styles are described from structural trends and sedimentary sequences within sedimentary basins in the Australian continental slope and shelf. These tectonic styles are related to sea-floor spreading events and plate-tectonic movements within the adjacent ocean floor. The same tectonic styles occur within sedimentary basins of different ages; Mesozoic and early Tertiary basins contain rift valley sequences and late Cainozoic basins contain geosynclinal sedimentary suites.Northwestern, western and southern continental margins reflect spreading events explained by an Atlantic-type model in which there are rift-valley sedimentary sequences. The oldest rift valleys in the northwest and the youngest rifts in the south formed ahead of Gondwanaland break-up. After sea-floor spreading commenced, the rate of continental margin collapse varied from place to place. The eastern and northeastern slopes and shelves border marginal seas and do not contain recognizable rift-valley sequences, except for tensional splays (triple junctions) in the Tasman Sea. Short-lived spreading within marginal seas started in the Late Cretaceous in the south and in the Paleocene in the northeast. The tectonism of the northern margin is mainly recorded on land in Timor, Irian Jaya and Papua New Guinea, where, in the Neogene to Holocene, the Australian continent collided with the Asian Plate at the Banda Arc and the sub-plates of the western Pacific at the Louisiade and Bismarck Arcs.     

中国区域成矿若干问题探讨

本文以区域大地构造演化和区域岩石圈组成为基础,将中国大陆划分为６个成矿域：天山－兴蒙成矿域,塔里木－华北成矿域。秦－祁－昆成矿域,扬子成矿域,华南成矿域,喜马拉雅－三江成矿域,并描述了它们的基本下,按照不同地质时代,简述了中国大地构造演化与主要矿床过程,并从中国近处大地构造背景和地质成矿演化历史出发,探讨了中国区域成矿特色,初步提出８点;（１）大陆边缘成矿显著;（２）发育叠加复合成矿作用;（３）壳     

论构造复合

构造复合现象在地壳岩石圈中普遍存在,它是构造运动多期次多阶段发展的记录。构造复合存在多种多样的形式,其基本形式不仅包括各种形迹的复合,建造与形迹的复合,而且包括建造与建造的复合;就其复合的空间位置而言,既有原地的复合,也有异地的复合;就运动方式而言,既有同方式运动的复合,也有不同方式运动的复合;就构造复合的规模和等级而言,小至小型或显微构造,中至露头规模的构造形迹复合,大至构造带、构造地块、构造体系乃至巨型构造域(岩石圈板块)的复合。
文章特别强调了复合构造域和区域构造体系等概念。用三大板块相互作用和构造复合的概念解释了存在于我国及其邻区的区域构造体系的形成机制。文章的最后提出了构造复合的若干基本规律。      

"第四届全国青年地质大会论文"专栏前言

2019年4月为贯彻国家对地质工作的新要求，以科技创新引领地质工作，在安徽合肥召开了“第四届全国青年地质大会”。来自全国各地的600多位青年地质工作者围绕“青年地质工作者--勇当金山银山的发现者，绿水青山的守护者”主题，集中研讨了有关地质的科学问题。本次大会由中国地质学会青年工作委员会承办，推动了系列科技成果的产出，更是为年轻人搭建相互学习、共同进步的平台。因此在《地学前缘》编辑部的支持下，征集组织了“第四届全国青年地质大会论文”专栏。稿件经过初审、外审、终审等环节，在古生物、岩石学、矿床学及环境学方面收录8篇文章：肖良等讨论了“浙东中新世菱属果实化石的数量分类”；陈珊等探讨了 “薄互层干涉对叠前AVO属性的影响分析”；张嘉玮等研究了 “湘黔桂新元古宙拉伸纪晚期地层年代格架对比及关键地质事件初探” ；朱强等展示了“扬子板块新元古代中期的持续俯冲作用：来自南华纪岛弧火山岩年代学和岩石地球化学新证据”；郭飞等讨论了“湖南栗山铅锌铜多金属矿床闪锌矿微量元素富集特征及成矿指示意义”；刘洪等探讨了“冈底斯西段罗布真浅成低温热液型银金矿的成矿流体演化：来自流体包裹体、H-O同位素的证据”；陈政宇等探讨了“柴达木旺尕秀煤矿东南晚侏罗世-早白垩世风成砂古风向及古地理意义”；陈国超等研究了“东昆仑造山带东段晚古生代-早中生代构造岩浆演化与成矿作用”。 本次由青年学者撰写的新发现、新进展和新成果论文，可以为广大地学工作者提供重要的地质科技参考资料。 在出版本栏目之际，我们不能不提到一个真实的小故事。 张嘉玮等的文章在经过二次评审通过后，最终被《地学前缘》编委会终审退稿，理由是能佐证论据的样品数太少(前面审稿专家也指出了此问题)。这是科研浮躁和急功近利之风盛行之下的普遍问题。当编辑部告知张嘉玮“退稿”或“补充样品分析数据重写再审”时，张嘉玮坚定地表示要重写。2020年三四月的日子是祖国大地新冠疫情肆虐之时，许多出行活动业已停止。但张嘉玮与科研团队逆行而上，他们爬大山，跨壕沟，走上了重新补采样品之路；他们打磨样品，详测数据，深入分析探讨，补充佐证数据。经过一系列艰苦工作，论文终被审稿通过并录用。 这个故事不仅告诉我们期刊的文风导向和审稿把关有多么重要，更彰显了年轻一代地学工作者勇于担当、坚韧不拔、不懈努力的进取精神，年轻的心灵终会因磨难的洗礼而变得更加博大。 感谢审稿专家对青年地质工作者的学术指导，感谢作者、编辑们为出版此栏目付出的辛勤劳动。     

Vortical tectonics

It is shown that lithospheric plates in their movement on the Earth’s surface do not undergo typical rotations, as was previously believed, but rather movements of a more complicated type, namely vortical (or “whirl”). The specific character of vortical movements is reflective in various structural-tectonic phenomena at the global, regional, and local levels. The discovery of vortical movements and structures in solid geospheres is evidence of concepts of nonlinear, unstable geophysical medium. At the same time, due to the exceptional duration of the formation of vortices in these geospheres, completely closed, matured vortical structures are rarely formed. Examples of the evolution of backarc basins in the junction zone of the Pacific Ocean and Eurasia are considered; these are evidence that energy vortical movements are sufficient to influence vitally the geodynamics of junction zones. It is suggested that the complex of lithospheric structures, being the result of vortical movements, can be considered within the specially marked out vortical tectonics, which is the key element of the re-formed geodynamical paradigm.     

大兴安岭中北段原岩锆石U-Pb测年及其与区域构造演化关系

作者认为单个锆石的同位素年龄记录了所在区域单次构造、岩浆或变质事件活动的时间,不同来源的大量原岩单颗粒锆石的测年数据则可以反映研究区总体构造演化历史。本文对近年来在大兴安岭中北段自测和收集的123件原岩样品的2636个锆石U-Pb测年点的同位素年龄进行统计,结果显示研究区的锆石年龄数据总体上出现840~780Ma, 530~440Ma, 330~280Ma, 240~190Ma,180~160Ma和150~120Ma等多个明显高峰值区间和>840Ma, 770~540Ma和440~400Ma三个相对数据较少的空白地段,且岩浆结晶锆石、变质锆石、继承性锆石等不同成因类型的锆石的年龄统计分布有良好的对应性。年龄数据的高峰值区间与该地区基底形成、陆壳生长、主要板块或微板块俯冲、碰撞、拼贴等主要构造事件时间吻合;而年龄空白区间则与主要的洋底扩张、被动陆缘时代相吻合。研究说明大量原岩锆石的测年数据与河流碎屑锆石同位素年代学一样,可以用于研究物源区的地壳生长和构造演化历史。综合大兴安岭中北段大量单颗粒锆石的同位素年代学、岩石组合和构造特征研究,说明该地区经历了古元古代基底形成、新元古代陆壳生长、新元古代末期板块裂解,古生代期间古陆块间的俯冲、拉张、拼贴碰撞,早中生代碰撞造山、晚中生代造山后伸展垮塌、大陆边缘弧后伸展等复杂的构造演化历史;同时表明蒙古-鄂霍茨克洋在早中生代时期(晚三叠世)即已碰撞造山,大兴安岭中北段及额尔古纳地区发育大量与碰撞有关的花岗岩、混合岩及碰撞后伸展跨塌有关的构造和岩石产物(盆岭构造、滑脱构造、变质核杂岩、陆相双峰式火山岩和多金属成矿等),这对于重新认识研究区中生代多金属成矿的地球动力学背景提供了新的依据。     

南海大陆边缘盆地构造演化差异性及其与南海扩张耦合关系

南海大陆边缘盆地由于边界条件的差异,不仅形成了不同类型的陆缘盆地,如离散型、走滑伸展型和伸展挠曲复合型,而且这些盆地构造演化存在明显的非同步性。这些陆缘破裂过程与南海扩张作用过程呈现明显不一致性。研究表明,南海扩张时期南海南、北大陆边缘均形成了一系列裂陷盆地,然而,南海南部、北部大陆边缘盆地裂陷作用结束时间不同,北部大陆边缘盆地裂陷作用结束于23 Ma或21 Ma,而南部大陆边缘盆地裂陷作用结束于15.5 Ma,显然北部大陆边缘盆地裂陷结束时间明显早于南部大陆边缘盆地。南海扩张停止后,南海南、北部陆缘仍表现出明显差异,北部陆缘仍以伸展作用为主,晚中新世以来出现快速沉降幕,而南海南部陆缘则以挤压作用为主,且其挤压时间及强度呈现南早北晚的特点,即南部曾母盆地明显早于南薇西盆地和北康盆地。南海南、北大陆边缘盆地形成演化的差异性,特别是构造转型差异变化,为新生代南海扩张的迁移性提供了有力的佐证,可以推断南海不同期次海盆扩张可能存在向南的突然跃迁。因此,本次研究梳理出的南海不同陆缘盆地张裂伸展的非同步性可为南海洋盆扩张演化过程解释提供新的证据。     

Generations of spreading basins and stages of breakdown of Wegener’s Pangea in the geodynamic evolution of the Arctic Ocean

Chronological succession in the formation of spreading basins is considered in the context of reconstruction of breakdown of Wegener’s Pangea and the development of the geodynamic system of the Arctic Ocean. This study made it possible to indentify three temporally and spatially isolated generations of spreading basins: Late Jurassic-Early Cretaceous, Late Cretaceous-Early Cenozoic, and Cenozoic. The first generation is determined by the formation, evolution, and extinction of the spreading center in the Canada Basin as a tectonic element of the Amerasia Basin. The second generation is connected to the development of the Labrador-Baffin-Makarov spreading branch that ceased to function in the Eocene. The third generation pertains to the formation of the spreading system of interrelated ultraslow Mohna, Knipovich, and Gakkel mid-ocean ridges that has functioned until now in the Norwegian-Greenland and Eurasia basins. The interpretation of the available geological and geophysical data shows that after the formation of the Canada Basin, the Arctic region escaped the geodynamic influence of the Paleopacific, characterized by spreading, subduction, formation of backarc basins, collision-related processes, etc. The origination of the Makarov Basin marks the onset of the oceanic regime characteristic of the North Atlantic (intercontinental rifting, slow and ultraslow spreading, separation of continental blocks (microcontinents), extinction of spreading centers of primary basins, spreading jumps, formation of young spreading ridges and centers, etc., are typical) along with retention of northward propagation of spreading systems both from the Pacific and Atlantic sides. The aforesaid indicates that the Arctic Ocean is in fact a hybrid basin or, in other words, a composite heterogeneous ocean in respect to its architectonics. The Arctic Ocean was formed as a result of spatial juxtaposition of two geodynamic systems different in age and geodynamic style: the Paleopacific system of the Canada Basin that finished its evolution in the Late Cretaceous and the North Atlantic system of the Makarov and Eurasia basins that came to take the place of the Paleopacific system. In contrast to traditional views, it has been suggested that asymmetry of the northern Norwegian-Greenland Basin is explained by two-stage development of this Atlantic segment with formation of primary and secondary spreading centers. The secondary spreading center of the Knipovich Ridge started to evolve approximately at the Oligocene-Miocene transition. This process resulted in the breaking off of the Hovgard continental block from the Barents Sea margin. Thus, the breakdown of Wegener’s Pangea and its Laurasian fragments with the formation of young spreading basins was a staged process that developed nearly from opposite sides. Before the Late Cretaceous (the first stage), the Pangea broke down from the side of Paleopacific to form the Canada Basin, an element of the Amerasia Basin (first phase of ocean formation). Since the Late Cretaceous, destructive pulses came from the side of the North Atlantic and resulted in the separation of Greenland from North America and the development of the Labrador-Baffin-Makarov spreading system (second phase of ocean formation). The Cenozoic was marked by the development of the second spreading branch and the formation of the Norwegian-Greenland and Eurasia oceanic basins (third phase of ocean formation). Spreading centers of this branch are functioning currently but at an extremely low rate.     

Origin and significance of olistostromes in the evolution of orogenic belts: A global synthesis

Olistostromes (sedimentary mélanges) represent the products of ancient submarine mass transport processes. We present a comparative analysis of the occurrences and internal structures of these sedimentary mélanges at a global scale with a focus on the Circum-Mediterranean, Appalachian and Circum-Pacific regions, and discuss their formation and time-progressive evolution in different tectonic settings. Lithological compositions, stratigraphy, and structural features of olistostromes reflect the operation of an entire spectrum of mass transport processes during their development through multi-stage deformation phases. The general physiography and tectonic setting of their depocenters, the nature, scale and rate of downslope transformation mechanisms, and global climatic events are the main factors controlling the internal structure and stratigraphy of olistostromes. Based on the tectonic settings of their formation olistostromes are classified as: (i) passive margin, (ii) convergent margin and subduction–accretion, and (iii) collisional and intra-collisional types. Systematic repetitions of these different olistostrome types in different orogenic belts provide excellent markers for the timing of various tectonic events during the Wilson cycle evolution of ocean basins. Olistostromes are best preserved in paleo active margins, covering vast areas of thousands of km², where they underwent significant downslope translation, up to hundreds of kilometers. Incorporation of olistostromes into subduction–accretion complexes and orogenic belts takes place during discrete episodes of tectonic events, and their primary (sedimentary) fabric may be commonly reworked and overprinted by subsequent phases of tectonic and metamorphic events. We apply the basic nomenclature of structural geology, sedimentology and basin analysis in studying the internal structure, lithological makeup, and mechanisms of formation and extraordinary downslope mobility of olistostromes.     

Geotectonic significance of ultramafic rocks

Ultramafic rocks can be divided into 5 principal geotectonic groups, as follows: (1) Layered gabbro-norite-peridotite masses, commonly associated with all ages of terrane, possibly connected with accretionary plate margins. (2) Concentrically zoned Alaska-type bodies, possibly associated with consuming plate margins. (3) Ultramafic lavas and associated intrusions, nearly exclusively in Archaean terranes, of uncertain tectonic position. (4) Alpine peridotites, in linear Phanerozoic and Late Precambrian deformed belts, indicative of activity both at accretionary and consuming plate margins. (5) Nodules and other ultramafic rocks associated with alkalic volcanic centers, which in some cases represent mid-plate activity, as well as direct samples of mantle rocks underlying the volcanic area. A key question in interpretation of the geotectonic significance of ultramafic rocks is the nature or even existence of plate-tectonic activity prior to that reflected in the present ocean basins.     

中生代多向挤压构造作用与四川盆地的形成和改造

远离活动板块边缘的四川盆地以其周缘复杂分布的褶皱构造带而著称,这些构造带的成因及其大地构造背景一直是华南大地构造研究的焦点之一。本文基于区域构造编图、褶皱构造样式和叠加变形分析,论述了四川盆地及其周缘中生代挤压变形特征及其定型时代,确定了重要构造事件及其产生的构造样式。研究显示,四川盆地及其周缘地带中生代经历了3个重大构造事件,每个构造事件产生的构造形迹在空间上发生复合和联合,造就了四川盆地及其周缘复杂的构造组合样式。中晚三叠世碰撞造山事件(印支运动)在扬子地区形成近W-E向褶皱构造,扬子地块西缘伴随着松潘—甘孜褶皱造山带的形成,发育了龙门山—锦屏山逆冲-推覆构造带及川滇前陆盆地,奠定了川—渝—黔—滇大型沉积盆地,构成四川盆地的原形。中晚侏罗世时期(燕山早幕),东亚构造体制发生重大变革,来自北部、东部、西部和南部的板块多向汇聚导致了大陆多向汇聚构造体系的形成和发展,其中秦岭造山带的再生活动导致南部米仓山—大巴山前陆构造带的形成和发展;来自太平洋板块向西推挤,导致了川东地区NW向突出的弧型构造和川南华蓥山帚状构造的形成;羌塘地块的向东侧向挤出,在扬子地块西北缘发生褶皱逆冲变形(龙门山—锦屏山构造带)。这期多向挤压事件强烈改造了四川T3-J1-2原形盆地,周缘褶皱构造带基本定型。早白垩世晚期的挤压事件(燕山晚幕)进一步改造了四川盆地,NW-SE向构造得到加强。除了西缘以外,四川盆地其他周缘褶皱构造带主体定型于晚侏罗世的陆内造山作用阶段,是扬子克拉通周边造山带在周邻板块多向汇聚作用下引发的再生复活的结果,成为中国东部陆内汇聚构造体系的重要组成部分。     

大陆边缘增生造山作用

文章评述了增生造山作用的研究历史和进展,认为增生造山作用贯穿地球历史,是大陆增生的重要方式。用大陆边缘多岛弧盆系构造理解造山带的形成演化,提出巨型造山系的形成与长期发育的大洋岩石圈俯冲制约的两侧或一侧的多岛弧盆系密切相关。在多岛弧盆系演化过程中的弧 弧和弧 陆碰撞,弧前和弧后洋盆的消减冲杂岩的增生,洋底高原、洋岛/海山、外来地块(体)拼贴等一系列碰撞和增生造山作用形成大陆边缘增生造山系。大洋岩石圈最终消亡形成对接消减带,大洋岩石圈两侧的多岛弧盆系转化的造山系对接形成造山系的联合体。拼接完成后往往要继续发生大陆之间的陆 陆碰撞造山作用、陆内汇聚(伸展)作用,后者叠加在增生造山系上,使造山过程更加复杂。对接消减带是认识造山系形成演化的关键。大洋两侧多岛弧盆系经历的各种造山过程可以从广义上理解为一个增生造山过程。多岛弧盆系研究对于划分造山带细结构非常重要,是理解造山系物质组成、结构和构造的基础,并制约了造山后陆内构造演化。大陆碰撞前大洋两侧多岛弧盆系及陆缘系统更完整地记录了威尔逊旋回,记录的信息更加丰富。根据多岛弧盆系的思路对特提斯大洋演化提出新的模式,认为西藏冈底斯带自石炭纪以来受到特提斯大洋俯冲制约,三叠纪发生向洋增生造山作用,特提斯大洋于早白垩世末最终消亡。     

Tectonic provinces of the Atlantic Ocean

The tectonic structure of the floor of the Atlantic Ocean beyond the continental margins is insufficiently studied. This is also true of its tectonic demarcation. The segmentation of the floor into regional-scale tectonic provinces of several orders proposed in this paper is primarily based on structural and historical geological features. It is shown that deep oceanic basins and fault tectonics are of particular importance in this respect. Tectonic provinces of two orders are distinguished by a set of attributes. The first-order provinces are the North, Central, South, and Antarctic domains of the Atlantic Ocean. They are separated by wide demarcation fracture zones into Transatlantic (transverse) second-order tectonic provinces. Ten such provinces are recognized (from the north southward): Greenland-Lofoten, Greenland-Scandinavia, Greenland-Ireland, Newfoundland-European, North American-African, Antilles-African, Angola-Brazil, Cape-Argentine, North Antarctic, and South Antarctic. This subdivision demonstrates significant differentiation in the geodynamic state of the oceanic lithosphere that determines nonuniform ocean formation and the tectonic features of the ocean floor. The latitudinal orientation of the second-order provinces inherits the past tectonic pattern, though newly formed structural units cannot be ruled out. The Earth rotation exerts a crucial effect on the crust and the mantle.     

吉林通化地区地洼型花岗岩与成矿的某些特征

Magmatism with its relation to mineralization has long been considered one of the important topics in geotectonics and metallogeny. Based on a rough summary of the geotectonic features of this region, a tentative investigation has been made on Mesozoic granitic rocks as related in time and space to mineralization. This region has experienced three major periods in its geotectonic evolution: the Presinian geosynclinal period, the platform period spanning from Sinian to Middle Triassic, and the diwa period beginning from Late Triassic. In accordance with these periods, three principal tectonic stages with their successive substages have been identified (See Fig. 1). During Late Triassic, the platform collapsed and yielded its place to a new type active region.-the diwa region. According to the present geotectonic features, this paper has divided the region into tectonic areas of various classes, indicating that EW and NE trending structural systems together with their combinations make up the basic tectonic framework. This paper has also described quite in detail some basic characteristics of diwa type granitic xocks and their related endogenic ore deposits, denoting that tectono-magmatic-matallogenic zones were formed spatially under the control of tectonic stages, tectonic areas and tectonic systems. ln the Jingyu geodome series, granitic rocks occur chiefly in diwa; in the Hunjiang diwa series, there exists JianFusong intense tectono-magmatic zone-one of the major endogenic metallogenic zone in this region. Different tectono-magmatic periods have been indicated in this paper with their respective ore types illustrated. The evolution in time and space of granitic rocks have been further demonstrated petrologically and geochemically. Petrochemical data of 164 samples from 35 intrusive bodies reveal that SiO₂, K₂O+Na₂O, Fe₂O₃+FeO+MgO and Fe₂O₃/FeO increase regularly from early to late periods, accompanied by an apparent evolution of rocks and minerals. All this implies that this region bears the basic characteristics of magmatic activities of Cathaysoid diwa in eastern China while has its own regional peculiarity in rock and ore formation-and geotectonic evolution. The earliest intrusion of the Early Yenshanian Period has quite different qualities as compared with intrusions of other periods in such aspects as rock types, petrochemistry and metallogenic specialization, suggesting the probale existence of another independent evolution series of magmatic source. The contents of minor elements reflect the geochemical characteristics and the inherent metallogenic evolution trend in this region. They are direct indicators for ore-bearing parent rocks, as evidenced by the coincidence of the high concentration of these elements with the anomalies of geochemical exploration and of heavy placer mineral prospecting.     

吉林通化地区地洼型花岗岩与成矿的某些特征

岩浆活动与成矿的研究,是大地构造与成矿学中的一个重要课题,它着重探讨构造运动—岩浆活动—成矿作用之间的密切关系。本文根据作者在区内历年野外工作所见,结合有关单位的资料,以地洼学说为指导,在总结区内大地构造基本特征的基础上,对中生代花岗岩类与成矿的时空分布和其特征作些探讨。     

雅鲁藏布江缝合带内构造岩片划分及形成——以仲巴-桑桑段为例

构造岩片作为造山带中非史密斯地层地区的填图单位有其重要的地质意义,本文将雅鲁藏布江缝合带分为6大构造岩片,其中蛇绿混杂岩岩片又分4个次级岩片,进一步阐述了缝合带内不同单元具有不同岩性和不同构造型式,是一条复杂的构造带,并发现俯冲板块一侧的不同构造单元具有自南而北,由脆性变形到低温高压变质、脆-韧性变形,超基性岩的深层次韧性变形的分布规律,大多数岩片的分布是通过多重逆冲推覆型或走滑型的断层将其从地壳深部挤出定位的。雅鲁藏布江缝合带内的构造岩片特征,反映了冈瓦那大陆北缘自三叠纪末期到第四纪经历了裂陷、扩张、多岛洋、闭合、俯冲、碰撞、褶皱、推覆造山的全过程。     

地球动力、构造发展和未来

从全球大地构造力学几何分析和天体演化学研究得知,地球的原始形态是卵形体,因此在向圆球体发展中必然产生两极挤压力成为总应力场。于是形成经向大洋的裂口和纬向褶皱,并出现了构造运动旋回。在此两极挤压中也诱发了岩浆活动和成矿,地震也由此而来。地球在现阶段趋向稳定,人类不必担心将有剧烈地壳构造运动,要爱护地球,节省资源,致力于环境和发展,为后代造福。     

新疆北天山晚古生代洋盆演化与推覆构造

通过实地考察并综合区域及深部物探资料,研究了北天山逆冲推覆系统的构造样式、结构特征和组合方式;认为北天山晚古代洋盆为板内地壳扩张活动形成的裂陷构造产物,存在时限短暂、对生物群迁移基本没有阻隔作用,不应具有分隔岩石圈板块的大地构造意义。     

On tectonophysical interpretation of recent vertical crustal movements

Recent crustal movements are components and the direct continuation of some neotectonic movements i.e. the Neogene-Quaternary stage of the earth's development. According to geodetic and oceanographic data these crustal movements are constantly taking place everywhere on the continents and probably on the ocean floor. Their velocity and velocity gradients are certainly different on platforms from that in orogenic regions. Orogenic regions are characterized by higher velocity, varying from several mm to several cm per year, and to an even greater degree by the different character of the movement. The velocity gradient in these regions reaches values of 10^?6–10^?5/year.A peculiar indication of recent movements is their irregularity in time. Periodic movements are typical for platforms; orogenic regions are characterized by sharp increases in velocity by 1–2 orders of magnitude and their gradients by 2–3 orders, close to the time occurrence of earthquakes.The deep processes generating the measured recent crustal movements are manifested also in earthquakes, the state of stress of rocks and anomalies of gravitational and other fields. Thus estimations of recent tectonic activity should be based on the whole complex of quantitative data, such as the velocity and velocity gradients of recent movements, values of stress in mines, and seismicity.To study the deep processes causing the present tectonic activity, it is necessary to determine the types of crustal deformation occurring in different geotectonic regions. The relationships between recent movements and the distribution of earthquakes in the regions with a high degree of crustal activity allow to identify four types of movement: pleistoseismic, hyposeismic, kryptoseismic and teleseismic.