共查询到17条相似文献，搜索用时 109 毫秒
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以位于秦岭—大别造山带之北、华北陆块南部、地跨华北陆块稳定块体、陆块南部边缘变形带的南华北盆地为研究对象,通过对研究区42条不同时代的野外剖面详细观测,运用层序地层学理论,把南华北盆地作为一个整体系统,对青白口系—侏罗系层序界面特征及时空分布规律进行了系统分析,共识别出了8种类型层序界面的物质表现形式,分别是不整合面、渣状层、古喀斯特作用面、冲刷侵蚀面、超覆面、岩性岩相转换面、最大海泛面、最大湖泛面。并重点讨论了各类型界面的时空分布特征。结果表明：在时间演化上,从早到晚由海相—海陆过渡相—陆相,层序界面经历了海相沉积不整合、古喀斯特作用面、渣状层到陆相不整合面、冲刷侵蚀面等;在空间上,同一层序界面在不同相带表现形式不同,同一种类型的界面可在不同相带出现,但不同相带表现特征有一定差异性。 相似文献
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中国东北兴蒙-吉黑造山带造山作用结束的标志——来自晚三叠世磨拉石(大地构造相)的证据 总被引：2，自引：0，他引：2
中国东北兴蒙-吉黑造山带广泛分布着晚三叠世的磨拉石建造,最有代表性者,一是产于造山带的双阳盆地的大酱缸组,底部具磨拉石特征的粗陆碎,堆积厚度大于400 m,上部含煤沉积,产Drepanzamites-Glocsophtllum.二是产于华北陆块及其北部陆缘造山带结合带上的抚松白水滩盆地的小营子组,下段砾岩段为磨拉石建造,厚大于351 m;上部细陆屑沉积,见多层碳质粉砂岩,产Cycadocarpidium?.sp.,Uniohuag bogoucnsis?.三是产于华北陆块上白山市石人镇石人盆地的小河口组,下段习称红石砬子砾岩,厚达570 m;上段北山含煤段产Danacopsis-Glossophyllum.它们与下伏早（中）三叠世地层或时代更老的地质体呈角度不整合接触.充分证明：兴蒙-吉黑造山带造山作用完成于早（中）晚三叠世之间,即结束于早印支期. 相似文献
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位于华北克拉通中部造山带内部的五台杂岩与毗邻的阜平、恒山杂岩是最经典的前寒武纪地质研究地区。被认为该地区最年轻的地质单元滹沱群不整合覆盖于五台和阜平杂岩之上。近来的工作越来越显示出滹沱群对于该地区乃至整个中部造山带的构造演化的重要性。然而对滹沱群沉积岩物源的缺乏认识阻碍了对该区沉积环境和构造意义的进一步研究。本文利用LA-ICP-MS,从滹沱群最底部的花岗质砾岩中获取了U-Pb锆石年龄,结合前人的地层学、地质年代学、构造地质学以及变质作用研究,对该地区底砾岩的沉积物源及大地构造演化提供了新的制约。滹沱群自下而上由底砾岩和火山碎屑岩(豆村亚群)、碎屑岩、板岩、白云岩和大理岩(东冶亚群)以及砂岩和另外一套出露于顶部的砾岩(郭家寨亚群)组成。来自于滹沱群底砾岩的花岗质砾石中的锆石获得了2517~2566Ma的207Pb/206Pb权重年龄,与五台新太古代的花岗岩(2566~2515Ma)年龄一致,说明这些花岗质砾石来源于五台新太古代花岗岩。结合前人的研究,滹沱群很有可能代表了一个发育在西部陆块向东部陆块俯冲过程中与俯冲相关的弧后前陆盆地。该盆地在约1850Ma华北克拉通最终碰撞拼合事件过程中闭合。滹沱群花岗质砾岩的... 相似文献
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豫西石千峰组研究新进展 总被引：4，自引：0，他引：4
豫西石千峰组很发育，分布广泛，据钻井的岩芯及化石划为三段，下段：平顶山砂岩段；中段：双壳类泥灰岩段；上段；石膏钙核段。平顶山砂岩段的地质时代为晚二叠世，地层上可同华北石千峰组下部对比，平顶山砂岩段同下伏上石盒子组为整合接触，经陆块南缘局部为不整合，称之海侵超覆，据石千峰组所含化石，说明华北陆块东南部晚二叠世为开阔海环境。 相似文献
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约1 000~820 Ma的新元古代青白口纪早期,全球罗迪尼亚超大陆汇聚的构造环境是中国该时期洋陆分布的主控因素;华北、扬子和塔里木三大陆块均位于当时地球的北半球,三大陆块的外围被边缘海和洋环绕.华北陆块周缘以稳定型的滨浅海沉积为主;而扬子陆块周缘表现为沟-弧-盆体系;塔里木西北缘发育阿克苏活动陆缘,塔里木北东缘和西南缘分别发育库鲁克塔格被动陆缘浅海碎屑岩建造和铁克里克被动陆缘碳酸盐岩建造.环绕华北、扬子和塔里木三大陆块的边缘海和洋内分布有众多裂离地块,多数地块亲扬子和塔里木陆块,如伊宁、敦煌、阿拉善、松潘、罗霄和武夷等;少数亲华北和西伯利亚陆块,如宝音图、锡林浩特、额尔古纳、韩家园、佳木斯和阿勒泰等. 相似文献
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鄂东南处于扬子地层区下扬子地层分区与江南地层分区交界处,南华系发育齐全,莲沱组由砾岩、砂岩、凝灰岩组成,岩性组合与扬子陆块内部可以很好的进行对比,而其与下伏地层假整合接触,与东南缘盆地相同;鄂东南的古城组、大塘坡组、南沱组表现出兼具扬子陆块内部及东南缘盆地的沉积特征;在接触关系上,各组间为整合接触,与东南缘盆地沉积特征相同。扬子陆块内部与东南缘盆地南华系对比仍存在分歧,鄂东南处于扬子陆块内部与东南缘盆地的过渡地带,为不同相区南华系对比建立了很好的桥梁。通过进一步工作,有望确定莲沱组、古城组等关键层位的对比等问题。 相似文献
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Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block.Geologic characters and spatial distributions of fve of these unconformities,which have resulted from different geological processes,have been studied.The unconformity beneath the Dahongyu Formation is interpreted as a breakup unconformity,representing the time of transition from continental rift to passive continental margin.The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fuctuations,leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands.The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting,whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event.It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents. 相似文献
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Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block.Geologic characters and spatial distributions of fve of these unconformities,which have resulted from different geological processes,have been studied.The unconformity beneath the Dahongyu Formation is interpreted as a breakup unconformity,representing the time of transition from continental rift to passive continental margin.The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fuctuations,leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands.The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting,whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event.It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents. 相似文献
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E. C. Willey 《Australian Journal of Earth Sciences》2013,60(1):139-152
Detailed field study in southeast Queensland has resulted in the interpretation of an unconformity at the base of the Esk Trough sequence at its contact with the Yarraman Block (Maronghi Creek beds and associated intrusions). Previously this contact had been considered to be faulted. The nature of the unconformity is very variable with the Esk Formation resting on freshly eroded surfaces, on mature palaeosols and on an immature palaeosol. Immediately above the unconformity, the Esk Formation variably comprises scree breccia, fluvial conglomerate and arenite, and alluvial fan conglomerate and arenite. North‐northwest‐south‐southeast‐striking faults are associated with the unconformity. Where the unconformity parallels these faults, it retains a relatively constant character, but where it is cut by these faults, it shows greater variability, a relationship interpreted to result from contemporaneous tectonism. The Glen Howden Fault extends into structurally disturbed areas previously described as ‘fractured anticlines’ and ‘complex anticlines’, which are here interpreted as flower structures and associated features. The south‐southeast extension of the Glen Howden Fault strikes obliquely across the Esk Trough to finally pass into the South Moreton Anticline previously interpreted as a positive flower structure, and resolves structural and stratigraphic observations that previously appeared anomalous. Inferred strike‐slip movement in the Esk Trough resulted from Early to Middle Triassic north‐northwest‐south‐southeast oblique transtension followed by Late Triassic transpression, and similar tectonism probably affected adjacent portions of the Yarraman Block. 相似文献
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不整合空间结构与油气成藏综述 总被引：10，自引：5，他引：10
不整合是由不整合面及其上、下岩石三部分组成,在空间上具有三层结构,即不整合面之上的岩石、不整合面之下的风化粘土层以及风化粘土层之下的半风化岩石。风化粘土层在上覆沉积物压实作用下岩性较致密,具有良好的封盖能力。不整合面之上的高孔渗岩石(主要为砂岩、砾岩)和不整合面之下裂隙、溶蚀孔洞发育的半风化岩石(主要为砂岩、砾岩、碳酸盐岩、火山岩及变质岩)既可作为油气运移通道,又可成为油气聚集的有效储层。由于构造部位、岩性等因素的影响,不整合空间结构复杂多变,导致不整合油气藏成藏规律复杂,因此,不整合空间结构研究对不整合油气藏勘探具有重要的指导意义。 相似文献
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<正>Precambrian tectonic history of Zhejiang,Fujian,and Jiangxi provinces of south China is important for understanding the tectonic evolution of South China but its magmatic activity, petrogenesis,stratigraphic sequence of the Mamianshan Group is still strongly controversial.Here we present new sensitive high resolution ion micro-probe(SHRIMP) U-Pb zircon geochronological data for the Mamianshan Group and petrographical data to constrain the tectonic framework of the regions.Our results showed that the SHRIMP U-Pb zircon age of green schists of the Dongyan Formation is 796.5±9.3 Ma,the Daling Formation is 756.2±7.2 Ma,and mica-quartz schist of the Longbeixi Formation is 825.5±9.8 Ma.These data indicate that the Mamianshan Group was formed not in the Mesoproterozoic,but in the Neoproterozoic and its stratigraphic sequences should be composed of Longbeixi,Dongyan,and Daling Formations from the bottom to the top.Rocks from this Group, from Zhejiang,Fujian and Jiangxi provinces,constituted the upper basement of the Cathaysia Block that overlay the lower basement of the Mayuan Group.Detailed petrographic studies demonstrate that the amphibole schists of the Dongyan Formation in the Mamianshan Group were formed within an intra-arc rift setting rather than a continental rift as previously suggested.Rather,this island-arc type formation was developed by collision and/or subduction between various blocks resulting from the breakup of the supercontinent Rodinia at c.850-750 Ma.The Zhuzhou conglomerate,distributed near Dikou Town,Jian'ou City,Fujian Province and previously considered as evidence of the Mesoproterozoic Dikou movement,is shown here not to be the basal conglomerate above the angular unconformity between the upper and lower basements.Our conclusions have important implications for understanding the Precambrian tectonics of South China. 相似文献
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华北陆块对Rodinia超大陆的响应及其特征 总被引：13，自引：0，他引：13
研究揭示华北陆块1300-1000Ma和800-650Ma都存在比较弱的岩浆-变质事件，它们可能对应于华南陆块的碰撞（四堡运动）和裂解事件。华北陆块的四堡期蛇绿混杂岩可能只见于新元古代秦岭造山带中。秦岭造山带北缘识别出了一些花岗质分清入体，它们具有碰撞或碰撞后花岗岩的特征。华北陆块北缘的火山沉积岩生活费不具有离散边界杂岩的特征，它们可能揭示了大陆边缘或者大陆伸展过程。华北陆块与800-650Ma事件相关的岩石主要为来自富集地幔的基性岩墙和来自陆内裂谷的沉积岩，它们很可能与Rodinia裂解有关。沉积学和古生物学特征表明元古宙华北陆块不同华南陆块，而与西伯利亚陆块相似。据此可以认为华北陆块是Rodinia超大陆的一部分，它位于超大陆的边缘，可以不与华南陆块紧邻，而与西伯利亚陆地较近。 相似文献
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Qinyan Wang Yuanming Pan Nengsong Chen Xiaoyan Li Haihong Chen 《Journal of Asian Earth Sciences》2009,34(5):686-698
The Quanji Block, situated close to the triple junction of three major Precambrian terranes in China (i.e., the North China Craton, the Yangtze Block and the Tarim Block), is composed of Precambrian metamorphic crystalline basement and an unmetamorphosed Mesozoic–Paleozoic sedimentary cover; it has been interpreted as a remnant continental fragment. Microtextural relationships, garnet trace element compositions, and monazite CHIME ages in paragneisses, schists and granitic leucosomes show two episodes of regional metamorphism in the Quanji Block basement. The first regional metamorphism and accompaning anatexis took place at ～1.93 Ga; the second regional metamorphism occurred between ～1.75 and ～1.71 Ga. Mineral compositions of the first metamorphism, including those of monazite, were significantly disturbed by the second event. These two regional metamorphic episodes were most likely linked to assembly and breakup of the supercontinent Columbia, respectively. 相似文献