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1.
扬子古板块构造有关问题探讨 总被引：1，自引：0，他引：1
根据已知地质事实，用历史分析法，探讨华南晚元古代至早古生代古板块构造轮廓及其演化史、认为当时华南地区存在扬子古板块和华夏微板块，晚元古代（含早震旦世）扬子古板块在其东南华南坳拉槽扩张推动下向北西漂移，在其前缘（北西侧）形成安第斯型主动大陆边缘，晚震旦世至早古生代，扬子古板块在秦岭海槽扩张推动下向南东漂移，在其前缘（南东侧）形成岛孤型主动大陆边缘。并通过与南海古板块的碰撞，形成华南加里东褶皱系，此过 相似文献
2.
闽,浙,赣晚前寒武纪构造格局探讨 总被引：4，自引：0，他引：4
华南前寒武纪构造格架在长期中不断取得进展。通过闽、浙、赣地区前寒武纪建造、构造综合分析研究：浙西－赣东北地区中元古代晚期为华夏古陆的活动陆缘;武陵运动是华南是重要的造山运动,华夏古陆与扬子板块在赣东北断裂带一线碰撞,形成了统一的“华南古大陆”;新元古代由于区域地质条件不同,各地块碰撞后的构造演化存有明显的差异;新元古代本区主要由华南新元古代早期大陆碰撞带和闽西南－赣南裂陷槽组成。 相似文献
3.
中国东南华夏板块的武夷山地块与罗霄地块之间存在一个非史密斯的地层带,称为雩山结合带.它是早古生代华夏板块与扬子板块拼贴过程中形成造山带的一个部分,自早奥陶世开始消减-中晚奥陶世主期挤压-中志留世伸展-晚志留世走滑四个阶段的非史密斯化过程. 相似文献
4.
华南早奥陶世海平面变化及其对比 总被引：5，自引：1，他引：5
本文在对扬子地台及其边缘寒武纪末至早奥陶世代表性剖以序地层，生态地层及生物地层综合研究基础上，讨论了华南板块碳酸盐台地及其陆棚－陆坡区早奥陶世海平面相对变化规律，指出该区在寒武幻末至早奥陶世至少可以识别出８次海退事件，阐明了这些海退事件发生的时间及其表现形式，并与国外进行了对比。 相似文献
5.
江西省地质构造格架及地壳演化 总被引：27，自引：1，他引：27
江西省从绍兴—萍乡—钦州古缝合线为界，分属扬子古板块与华南古板块。历经中元古代早期、新元古代早期等裂谷时用、四堡、加里东、印支、燕山等构造运动。包括５个地壳演化阶段，即早寒武纪原始陆壳形成阶段，中元古代扬子、华夏等古地体活动阶段，新元古代至早古生代扬子、华南古板块与华南陆间裂谷带活动阶段，晚古生代至中三叠世华南大陆形成阶段以及中、新生代欧亚板块活动与华南大陆“活化”阶段，形成了以“南北分野”的古构造基础，以中新生代“向洋分带”为主导的复合构造格局。 相似文献
6.
新疆古生代构造—生物古地理 总被引：4，自引：0，他引：4
通过6幅图表达了新疆古生代板块的构造－生物古地理区系。早古生代，包括劳伦，波罗的、西伯利亚和哈萨克斯坦4陆块的亚帕特斯古陆（Iapetusa)群，与由其余陆块构成的冈瓦纳古陆群隔原特提斯洋相对峙。石炭－二叠纪，欧美、安加拉、太平洋和冈瓦纳4古陆共存并立。西伯利亚和哈萨克斯担板块经历了早古生代亚伯特斯古陆、晚古生代安加拉古陆和早二叠世晚期以来欧亚大陆3个发展阶段。塔里木、中朝、华南－东南亚板块经历了早古生代冈瓦纳古陆、晚古生代太平洋古陆和早二叠世晚期以来欧亚大陆3个发展阶段。指出在中晚寒武世和晚奥陶世哈萨克斯坦板块靠近塔里木、中朝和华南－东南亚板块；在早古生代其余时期它接近西伯利亚板块。伊犁和托克逊－雅满苏地体是在中泥盆世之前裂解自塔里木板块，尔后在早二叠世晚期接近安加拉古陆。塔里木板块北东缘北山地区在早二叠世早期首先靠近安加拉古陆。塔里木与西伯利亚－哈萨克斯坦板块之间缝合时代大抵上和土耳其－中伊朗－冈底斯与华南－东南亚板块之间缝合时代一致。缝合事件发生在早二叠世早期，而相应的构造运动出现在早晚二叠世之交。 相似文献
7.
论西昆仑大陆边缘构造演化及塔里木西南盆地类型 总被引：13，自引：3，他引：10
中元古代至早古生代塔里木板块与羌塘－扬子板块发生解体。晚古生代至三叠纪西昆仑演化为活动大陆边缘,自南而北形成了公洛尔－桑株塔克、库尔浪－卡尔隆沟、弧、盆体系,塔里木西南则于这一时期发展成为克拉通坳陷型盆地。三叠纪末塔里木板块与羌塘－扬子板块碰撞,以及中、新生代以来特提斯开与合的“手风琴“式运动施加的影响,使西昆仑发生了强烈的变质、变形和变位。 相似文献
8.
安徽沿江中新生代盆地位于大别山造山带南缘，为先挤压、后伸展形成的叠合盆地，是探讨扬子板块陆内深俯冲—大别山造山带隆起与中、下扬子盆地沉降的耦合关系的理想场所。在早中生代，大别山为华南和华北大陆碰撞造山带，华南地壳向深处俯冲并承受超高压变质作用，超高压变质岩不断向上折返，沿江坳陷具有前陆盆地性质，盆地充填有晚三叠世—中侏罗世磨拉石层序；在晚中生代，在中国东部整体的拉张背景下，大别山变质带完全折返上隆，处于变质核杂岩隆升状态，而沿江坳陷具有裂陷盆地性质，充填有晚侏罗世—早白垩世、晚白垩世—古近纪两个红色碎屑构造层序，起因于地壳拆沉而产生的均衡隆升和伸展断陷的构造耦合。 相似文献
9.
贵州黔南独山地区处扬子陆块东南缘,出露较完整的下古生界地层,对该区开展碎屑锆石U-Pb年龄谱研究可为晚古生代之前扬子地块与华夏地块结合带构造属性的进一步确定和对华南大地构造演化的深入研究提供新依据。本文对该区下泥盆统丹林组5件石英砂岩分析了375颗碎屑锆石:锆石阴极发光具有典型的振荡环带、不规则分带,Th/U比值多大于01,强Ce正异常、弱Eu负异常特征;346组谐和年龄显示来自多个源区,5组主要年龄峰值2 456 Ma、1 366 Ma、970 Ma、536 Ma、402 Ma,以970 Ma为最突出峰值。研究认为古生代锆石源于桂北-湘西内陆加里东期花岗岩、新元古代锆石主要来自江南造山带内新元古代四堡群、丹州群的火成岩;中元古代-太古宙锆石可能从华夏板块内部搬运到扬子板块。进一步论证了古生代华夏板块和扬子板块之间不存在沉积阻隔区,是一个整体板块;丹林组沉积于华南地块内的一个克拉通盆地。 相似文献
10.
华南大陆的结构、属性、过程与动力学一直是地质学家关注的热点。本文以钦杭构造带东段为主要研究地区,通过精细的构造解析、变质变形研究、年代学分析,结合反射地震剖面,探讨了华南大陆东部几个科学问题。（1）江南造山带形成于新元古代华夏板块与扬子板块的“软碰撞”作用,可划分为扬子板块南缘、扬子—华夏汇聚带和华夏板块北缘3个构造单元,江南断裂带和武夷山—遂昌断裂带分别为江南造山带的北界和南界。（2）扬子—华夏板块汇聚带由多个小板块拼合而成,其间有多条缝合带,大约900 Ma开始汇聚,760 Ma全面闭合,850~780 Ma为活动高峰期,具有递变式的汇聚拼合过程,由南向北发展,先斜向俯冲,后右旋走滑,最晚集中在中部活动。（3）华南大陆东部为中生代奠定的构造格架,主要构造为一系列北东走向褶皱和逆冲断层,大量地壳范围内的叠瓦状逆冲推覆构造,由南向北逆冲,可下切到中—下地壳。（4）华南大陆燕山晚期区域性伸展构造广泛发育,存在“华南热隆”构造,震旦系内的滑覆构造典型,同期大规模岩浆活动、火山活动和大规模的热液成矿。（5）华南大陆构造演化为：850 Ma扬子—华夏板块递进式汇聚,760 Ma全面拼合,江南造山带形成;600 Ma华南大陆盖层发育;430 Ma钦杭构造带受南部构造影响;220 Ma钦杭构造带受北部远程构造影响;160 Ma逆冲推覆构造产生;140 Ma大规模伸展,构造-岩浆-成矿关系密切;随后江南持续隆升,华南强烈热隆。 相似文献
11.
Previously proposed methods of area selection for diamond-prospective regions have predominantly relied on till geochemistry, airborne geophysics, and/or an appraisal of tectonic setting. Herein we suggest that a novel, deep-probing geophysical technique—electromagnetic studies using the natural-source magnetotelluric (MT) method—can contribute to such an activity. Essentially, diamondiferous regions must have (1) old lithosphere, (2) thick lithosphere, and (3) lithosphere that contains high concentrations of carbon. Deep-probing MT studies are able to address all three of these. The second and the third of these can be accomplished independently using MT, but for the first the geometries produced from modelling the MT observations must be interpreted with appropriate interaction with geologists, geochemists and other geophysicists. Examples are given from the Slave and Superior cratons in North America, with a brief mention of an area of the Rae craton, and general speculations about possible diamondiferous regions. 相似文献
12.
LIU Jianfeng LI Jinyi CHI Xiaoguo ZHENG Peixi HU Zhaochu ZHANG Xiaowei 《《地质学报》英文版》2020,94(4):1071-1092
The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relationship with the host pluton. Furthermore, the coeval magmatic assemblage and its petrogenesis on the northern margin of the North China craton(NCC) are studied synthetically to elucidate their tectonic setting and the implications for the destruction of the NCC. Zircon U-Pb dating reveals that the mafic enclaves formed at 230.4 ± 2.2 Ma, which is similar to the age of the host pluton. The most basic mafic enclaves belong to weak alkaline rocks, and they display rare earth element(REE) and trace element normalized patterns and trace element compositions similar to those of ocean island basalt(OIB). In addition, they have positive εNd(t) values(+3.84 to +4.94) similar to those of the Cenozoic basalts on the northern margin of the NCC. All of these geochemical characteristics suggest that the basic mafic rocks originated from the asthenosphere. Petrological and geochemical studies suggest that the Jiefangyingzi pluton and the intermediate mafic enclaves were formed by the mixing of the asthenosphere-derived and crust-derived magmas in different degrees. The Mid-Late Triassic magmatic rocks on the northern margin of the NCC could be classified into three assemblages according to their geochemical compositions: alkaline series, weak alkaline–sub-alkaline series and sub-alkaline series rocks. Petrogenetic analyses suggest that the upwelling of the asthenosphere played an important role in the formation of these Mid-Late Triassic magmatic rocks. Basing on an analysis of regional geological data, we suggest that the northern margin of the NCC underwent destruction due to the upwelling of the asthenosphere during the Mid-Late Triassic, which was induced by the delamination of the root of the collisional orogeny between Sino-Korean and Siberian paleoplates in Late Permian. 相似文献
13.
Travel times from earthquakes recorded at two seismic networks were used to derive an average P wavespeed model for the crust and upper mantle to depths of 320 km below southern Africa. The simplest model (BPI1) has a Moho depth of 34 km, and an uppermost mantle wavespeed of 8.04 km/s, below which the seismic wavespeeds have low positive gradients. Wavespeed gradients decrease slightly around 150 km depth to give a ‘knee’ in the wavespeed-depth model, and the wavespeed reaches 8.72 km/s at a depth of 320 km. Between the Moho and depths of 270 km, the seismic wavespeeds lie above those of reference model IASP91 of Kennett [Research School of Earth Sciences, Australian National University, Canberra, Australia (1991)] and below the southern African model of Zhao et al. [Journal of Geophysical Research 104 (1999) 4783]. At depths near 300 km all three models have similar wavespeeds. The mantle P wavespeeds for southern Africa of Qiu et al. [Geophysical Journal International 127 (1996) 563] lie close to BPI1 at depths between 40 and 140 km, but become lower at greater depths. The seismic wavespeeds in the upper mantle of model BPI1 agree satisfactorily with those estimated from peridotite xenoliths in kimberlites from within the Kaapvaal craton.The crustal thickness of 34 km of model BPI1 is systematically lower than the average thickness of 41 km computed over the same region from receiver functions. This discrepancy can be partly explained by an alternative model (BPI2) in which there is a crust–mantle transition zone between depths of 35 and 47 km, below which seismic wavespeed increases to 8.23 km/s. A low-wavespeed layer is then required at depths between 65 and 125 km. 相似文献
14.
华北克拉通东部早白垩世伸展盆地的发育过程及其对克拉通的破坏 总被引：1，自引：0，他引：1
在晚侏罗世华北克拉通东部破坏之初出现了区域性隆起,全区缺失上侏罗统沉积。在早白垩世早期,出现了区域性的伸展活动,断陷盆地形成,克拉通南、北缘伸展活动最强,北部燕山构造带以出现变质核杂岩为特征,南部出现宽裂谷型盆地。早白垩世中期华北克拉通东部普遍出现了火山活动与岩浆侵入。早白垩世晚期克拉通上以出现窄裂谷型盆地为特征,沿北北东走向的郯庐断裂带断陷活动最强。这些断陷盆地的演化过程揭示,经历地表抬升后,克拉通破坏之初的岩石圈热而弱,从而形成变质核杂岩或宽裂谷型盆地。这期间的破坏强度在空间上具有不均匀分布的特征,受控于早期岩石圈地幔的结构。经过早白垩世中期的大量岩浆活动之后,早白垩世晚期克拉通岩石圈温度降低、强度变大,从而利用早期大型断裂构造形成窄裂谷型盆地。这现象支持华北克拉通东部晚中生代的岩石圈减薄是以逐渐拆沉机制为主。 相似文献
15.
New geochemical data of the crater-facies Tokapal kimberlite system sandwiched between the lower and upper stratigraphic horizons of the Mesoproterozoic lndravati Basin a：：e presented. The kimberlite has been subjected to extensive and pervasive low-temperature alteration. Spinel is the only primary phase identifiable, while olivine macrocrysts and juvenile lapilli are largely pseudomorphed （talc-serpentine- carbonate alteration）. However, with the exception of the alkalies, major element oxides display systematic fractionation trends; likewise, HFSE patterns are well correlated and allow petrogenetic interpretation. Various crustal contamination indices such as （SiO2 ＋ AI：：O3 ~ Na20）]（MgO ~ K20） and Si] Mg are close to those of uncontaminated kimberlites. Similar La]Yb （＇79-109） of the Tokapal samples with those from the kimberlites of Wajrakarur （73-145） and Narayanpet （72-156）, Eastern Dharwar craton, southern India implies a similarity in their genesis. In the discriminant plots involving HFSE the Tokapal samples display strong affinities to Group 1I kimberlites from southern Africa and central India as well as to ＇transitional kimberlites＇ from the Eastern Dharwar craton, southern India, and those from the Prieska and Kuruman provinces of southern Africa. There is a striking ~;imilarity in the depleted-mantle （TOM） Nd model ages of the Tokapal kimberlite system, Bastar craton, th~ kimberlites from NKF and WKE Eastern Dharwar craton, and the Majhgawan diatreme, Bundelkhand craton, with the emplacement age of some of the lamproites from within and around the Palaeo~Mesoproterozoic Cuddapah basin, southern India. These similar ages imply a major tectonomagmatic event, possibly related to the break- up of the supercontinent of Columbia, at 1.3-1.5 Ga across the l：hree cratons. The ＇transitional＇ geochemical features displayed by many of the Mesoproterozoic po~：assic-ultrapotassic rocks, across these Indian cratons are inferred to be memories of the metasomatisi 相似文献
16.
华南扬子与华夏陆块古-中元古代基底地壳微量元素地球化学示踪探讨 总被引：10，自引：1，他引：9
从早期宙以垂向分异增长为主的思路出发,将华南扬子陆块和华夏陆块变质基底中相似岩类（陆源碎屑岩、变基性火山岩夹层和晋宁期花岗岩类）作为研究对象,选择了相容性接近的７对元素（Ｒｂ／Ｃｓ、Ｓｒ／Ｂａ、Ｔｈ／Ｕ、Ｎｂ／Ｔａ、Ｚｒ／Ｈｆ、Ｐｄ／Ｐｔ和Ｃｒ／Ｎｉ）作为示踪手段,对华南大陆古－中元古代基底的物源特征和后期演化进行了探讨,得出了几点初步认识：（１）扬子、华夏两陆块前元古宙“原始”地壳具有相近的物质 相似文献
17.
This is a synopsis of available data the on crustal structure and properties of thirteen Archean cratons of Gondwanaland (the cratons of Africa, Australia, Antarctica, South America, and the Indian subcontinent). The data include estimates of surface area, rock age and lithology, Moho depth, thickness of lithosphere and sediments, as well as elevations, all summarized in a table. The cratons differ in size from 0.05 x 106 km2 (Napier craton) to 4 x 106 km2 (Congo craton) and span almost the entire Archean period from 3.8 to 2.5 Ga. Sediments are mostly thin, though reach 7 km in the Congo and West African cratons. Elevations above sea level are from 0 to 2 km; some relatively highland cratons (Kaapvaal, Zimbabwe, and Tanzanian) rise to more than 1 km. On the basis of regional seismic data, the Moho map for cratons has been improved. The Moho diagrams for each craton are constructed. The analysis of the available new data shows that the average Moho depth varies from 33 to 44 km: Pilbara (33 km), Grunehogna (35 km), Sao Francisco (36 km), Yilgarn (37 km), Dharwar (38 km), Tanzanian (39 km), Zimbabwe (39 km), Kaapvaal (40 km), Gawler (40 km), Napier (40 km), West Africa (40 km), Congo (42 km), and Amazon (44 km) cratons. The Moho depth within the cratons is less uniform than it was assumed before: from 28 to 52 km. The new results differ significantly from the earlier inference of a relatively flat Moho geometry beneath Archean cratons. According to the new data, early and middle Archean undeformed crust is characterized by a shallow Moho depth (28-38 km), while late Archean or deformed crust may be as thick as 52 km. 相似文献
18.
We discuss historical evidence for seismicity on the southern margin of the Siberian craton collected from old local newspapers. The reported earthquakes vary in magnitude from M = 2.5 to 4.5, and their macroseismic locations agree well with the regional tectonic framework. The new data prove seismic activity in the area and can be used in seismic risk assessment. 相似文献
19.
早前寒武纪克拉通过去认为是地槽演化的结果。其实不然。本文讨论形成它们变质原岩火山－沉积建造的大地构造条件。现成早前寒武纪克拉通火山沉积盖层的成熟沉积岩丰富了孔兹岩原岩。它们面状展布，经常是很长时期形成的，这改进了识别早前寒武纪克拉通地台式变质原岩建造的标志。这类标志遍及七大洲，高级区和绿岩带。有理由认为，早前寒武纪克拉通是在老克拉通盆地里的地台式火山－沉积建造经变质－混合岩化－塑性流变－硬化的产物。 相似文献
20.
首次对华北板块东部早古生代克拉通边缘盆地的碳酸盐地层进行层序地层学剖析,认为从寒武纪至早奥陶世加积、侧积的碳酸盐层序主要受海平面升降所制约,为历时约110 Ma的一个海进—海退旋回,是与全球海平面升降同步的超周期(二级旋回,P.R.Vail,1978)。而且海面升高与海侵同步,其间被Ⅰ、Ⅱ型层序界面不整合分隔为四个层序。海面升降模式是缓慢的海进,快速的海退,在主体海退过程中层序界面及海面降低控制着蒸发岩(石膏)矿床的形成。对长期争议的“三山子”白云岩的成因问题提出了新认识:“三山子”白云岩系海面区际性下降过程中,淡水渗流作用下形成的准同生交代白云岩,并随海面向北退却而使白云岩化向北推移且层位升高,是穿时性的“淡水透镜体”的向盆迁移,是区际性层序界面不整合的重要标志。 相似文献