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1.
中国华南大陆构造与问题 总被引：30，自引：0，他引：30
在前人成果基础上,通过以构造为主的多学科综合调研,重新审视认知华南大陆构造及其形成演化．厘定新元古代以来该大陆具有二大地块、三大类型构造单元与四大变形构造系统,由此构成华南大陆构造基本格局．研究揭示其不同构造演化阶段具有不同性质和机制及构造特征,经历了四个不同属性特点的演化阶段,包括：（1）新元古代古板块构造的拼合与裂解,尤其陆内伸展裂谷构造;（2）显生宙以来在板块构造围限下的早古生代与中生代初两期陆内造山作用,形成两期复合的陆内造山构造区;（3）统一华南大陆内扬子克拉通与陆内造山的长期并行演化和克拉通的多期逐次迁移活化;（4）中新生代现代全球板块构造体制下的板块构造与陆内构造的复合差异演化及动力学特征．本文旨在综合多学科研究,对比中国大陆与全球地质,总结华南大陆构造的基本特征、属性以及所反映的具有普适性的大陆特性和构造规律并梳理有待进一步探讨的主要科学问题,从而系统地探讨大陆构造与成因及动力学机制,探索回答板块构造尚不能解决的大陆问题,深化发展板块构造,为构建大陆构造与大陆动力学理论系统做出努力． 相似文献
2.
集结“中国（东亚）大陆构造与动力学”为主题的科学与技术前沿论坛的11个论题,梳理了中国（东亚）大陆构造与动力学领域的四大关键问题：（1）古大陆、古环境、古构造及中国（东亚）古大陆的形成;（2）中国大陆增生与碰撞造山系的造山过程;（3）中国大陆的盆．山体系及近海新生代盆地的形成演化;（4）中国大陆的现代地壳活动及深部结构．综述了中国（东亚）大陆在长期地质历史中的聚合、裂解、碰撞和造山的过程,突显中国大陆构造体制的长期性、复杂性、叠置性、再造性和与洋．陆转换的成因联系．中国（东亚）三大构造域的关系、地体边界的超高压变质带和深地幔作用、印度／亚洲碰撞和青藏高原的隆升、近海新生代盆地的形成,大型断裂与地震、华南大地构造等问题已成为当前中国大陆构造及动力学领域关注的热点． 相似文献
3.
华北克拉通新太古代末超大陆拼合及古元古代末-中元古代裂解 总被引：72，自引：8，他引：64
华北克拉通在形成和演化中经历的最重要的地质事件发生在 ２ ６００～２ ４００和２ ０００－１７００ Ｍａ期间（简称 ２５亿年地质事件和 １８亿年地质事件）．提出这两个事件的实质是：古老的微陆块以规模较小的板块构造形式拼合成超大陆,以及超大陆受古地幔柱构造的影响再裂解成不同的陆块． 相似文献
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利用中国地震台网和ISC台站1980～2004年的地震数据，反演了南海东北部及其邻近地区的Pn波速度结构和各向异性.上地幔顶部的速度变化揭示出区域地质构造的深部特征：华南地区速度较高并且变化平缓，具有构造稳定地区的岩石层地幔特征；华南沿海尤其是滨海断裂带附近出现低速异常，表明该断裂可能穿过壳幔边界深达上地幔顶部.南海北部至台湾海峡较高的速度与华南地区类似，反映出大陆边缘和陆架地区的岩石层地幔性质；西沙海槽附近较高的速度不仅反映了华南大陆向南的延伸，而且与海槽裂谷拉张引起的地幔上拱有关，整个南海北部没有发现大规模地幔热流的活动痕迹.相比之下，南海东部次海盆的上地幔顶部存在明显的低速异常，对应于海底扩张中心的地幔上涌区，表明岩石层地幔强烈减薄甚至缺失；台湾东部－吕宋－菲律宾北部的低速异常与地震、火山活动以及岩浆作用紧密相关，揭示了西太平洋岛弧俯冲带的活动特征；南海东北部的洋－陆边界清晰，南海东部和菲律宾海西部较高的速度代表了海洋岩石层地幔的性质.Pn波各向异性反映出区域性构造应力状态及岩石层地幔的变形痕迹：华南地区的各向异性较小，说明这一构造稳定地区的岩石层地幔变形程度较弱；南海北部的快波方向与地壳浅表层构造的伸展方向一致，主要反映了中、新生代以来的大陆边缘张裂和剪切作用对岩石层地幔结构的影响；琉球－台湾－吕宋岛弧两侧各向异性十分强烈，平行于海沟的快波方向表明菲律宾海板块和欧亚大陆的相互作用导致俯冲板块前缘的岩石层地幔强烈变形；台湾东南海域快波方向的变化可能与欧亚大陆和菲律宾海板块俯冲机制的转换以及岩石层被撕裂有关. 相似文献
5.
华南中生代构造-岩浆活动研究：现状与前景 总被引：10，自引：0，他引：10
华南陆块是由华夏地块和扬子克拉通在新元古代早期碰撞拼贴形成,在古生代时期其北侧、西侧和南侧受到古特提斯洋消失的影响,在晚古生代末期在南、北两侧分别与印支陆块和华北陆块发生碰撞形成现今中国大陆东部的基本格架,自中生代起受到太平洋板块向西俯冲的影响．因此,华南陆块经历了三大构造体系的作用,产生了叠加复合型构造样式．华南与周边地区有关中生代地质的对比研究表明,尽管华南陆块中生代紧邻西太平洋俯冲带,但东缘尚未发现有新生的弧型地壳,华南中生代地质特征主体表现为吉大陆边缘再造至陆内构造,缺乏洋岛玄武岩和大陆弧安山岩．研究华南中生代构造．岩浆活动的重点,是确定华南中生代岩浆岩的时空展布和构造演化．本文通过总结华南具有挤压．伸展构造转换的三条结合带的岩浆岩记录,结合构造变形和深部地球物理资料,试图推动华南地质研究,使其成为发展板块构造理论的典型靶区． 相似文献
6.
中国主要古陆与联合大陆的形成——综述与展望 总被引：5，自引：0，他引：5
翟明国 《中国科学:地球科学》2013,(10):1583-1606
中国主要的古老陆块有华北、华南和塔里木,这些古陆在前寒武纪有各自独立的构造演化历史．华北陆块的前寒武纪构造演化记录最复杂也最完整,从古陆核的形成、巨量陆壳的生长和克拉通化,继而经历了古元古代裂谷．岛弧．碰撞构造事件和大氧化事件,中．晚元古代的裂谷事件代表了华北克拉通的地台属性的演化史．塔里木盆地的基底包括太古宙和古元古代的变质岩系以及新元古代地层,确定有三期冰川作用造成的新元古代冰躜岩．华南古陆是由扬子和华夏克拉通在新元古代拼接而成的．扬子克拉通经历了早前寒武纪的陆壳生长,而后发生了10～9亿年的和8-6亿年的两期变质与岩浆事件,此外,新元古代的两次冰川作用可与全球雪球事件对比．华夏古陆由18亿年、10—9亿年和约8亿年的古老花岗（片麻）岩以及变质岩组成,说明广泛的古老基底存在．华夏与扬子克拉通有统一的新元古代沉积盖层表明华南大陆至少形成在约10～9亿年后,并构成Rodinia超大陆的组成部分．中央造山系的高压．超高压变质作用研究支持了上述古陆块在三叠纪全球Pangea造山作用时期拼合在一起,形成中国大陆的主体． 相似文献
7.
根据前人对地幔流体力学数值模拟、全球地震层析成像和火成岩方面的研究成果，详细叙述了地幔柱的基本特征，即:地幔柱具有巨大的球状顶冠和细窄尾管的形态，具备高温、低粘的物理性质，来自2 900 km处核/幔边界附近的D层. 大火成岩省（LIP）是地幔柱到达地表最好的表现形式. 基于地幔柱、大火成岩省的基本特征，以及地幔柱和大陆解体的时空关系，通过对中国东部中、新生代火成岩的岩石学、地球化学和时空分布特征， 以及这些火成岩产生的构造背景等方面的研究，认为中国东南地区中生代火成岩与典型的地幔柱有关的LIP的基本特征并不符合，不能把东南地区中生代火成岩作为典型的与地幔柱活动相关的大火成岩省的实例来看待；东北地区新生代火成岩不具备热点、地幔柱活动的典型特征，新生代火山活动与地幔柱活动可能没有直接关系. 相似文献
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9.
川西新元古代基性岩墙群的SHRIMP锆石U-Pb年龄、元素和Nd-Hf同位素地球化学: 岩石成因与构造意义 总被引：7，自引：0，他引：7
扬子块体西缘新元古代岩浆活动非常强烈, 其成因对研究Rodinia超大陆的演化有重要意义. 目前对这些岩浆岩的成因和形成的构造背景存在地幔柱和岛弧两种截然不同的观点. 本文对川西康滇裂谷中康定-泸定-石棉地区广泛分布的基性岩墙群, 进行了SHRIMP锆石U-Pb年龄、元素和Nd-Hf同位素研究, 结果表明这些基性岩墙群形成于780 ~ 760 Ma, 与康定花岗质杂岩在时-空上密切共生. 岩浆起源于亏损的软流圈地幔, 虽然在上升侵位过程中受到年轻岛弧地壳物质不同程度的混染, 但元素和Nd-Hf同位素仍表现出板内玄武岩的特征, 很可能是高温地幔柱部分熔融的产物. 本文的研究结果支持华南位于澳大利亚和Laurentia大陆之间的Rodinia超大陆重建模式. 相似文献
10.
地震波速度结构层析成像和地震各向异性分析,是推测现今地幔流动的主要观测依据．从已有研究结果看,全球尺度的地幔流动的两个主要边界驱动力是顶部的冷却和底部的加热,地幔的密度和粘度控制流动速率．沿海沟由消减板带动的地幔下沉,和沿热点下面幔柱及洋中脊的地幔上升,是地幔垂直向流动的表现．GPS等测量显示的全球板块运动在一定条件下反映地幔顶部的水平流动．地幔柱可能有不同的根源深度,沿幔柱上升的地幔流在200—350km深度转变为水平流动．消减带附近有复杂的地幔流动格局,表明局部构造条件对地幔流动的影响．大陆下一般出现两个地幔各向异性层,较深的可能反映地幔流动,并与大陆根的状态有关．在不同构造环境下,地幔流动与板块构造之间有不同形态的相互作用关系,它可能驱动板块运动,也可能对板块运动产生阻力。 相似文献
11.
对人工地震测深及天然地震面波体波三维层折反演数据进行统一处理，建立了中国及其邻区地球三维结构初始模型．此模型图像表明，中国及其邻区地球各圈层横向变化明显．岩石圈及软流圈内速度分布主要反映这一区域自古生代以来板块及地块拼合模式．各主要板块或地块（塔里木、扬子、中朝、青藏、哈萨克斯坦、印度、印度支那）岩石圈增厚或有很深的地慢根，板块或地块间的造山带岩石圈减薄，软流圈速度降低。下地幔底部及核幔边界D″层出现高速异常，表明古太平洋及古特提斯洋俯冲板块因重力坍塌已进入地球深层，形成亚洲超级下降地幔柱。这一下降地幔柱引起地球表层物质向中亚、东亚地区集中，印度半岛、青藏高原、新疆、蒙古至贝加尔一带，成为全球岩石圈最大的汇聚场所． 相似文献
12.
目前研究一般认为华南块体是由扬子块体和华夏块体在新元古代拼合形成,并同时形成位于扬子块体东南边缘的江南造山带.但是由于华南地区构造历史复杂,对于扬子块体与华夏块体的分界及构造属性仍存在较大争议.为了研究华南块体的地下速度结构及构造属性,我们利用块体交界处的九嶷山及其附近的流动和固定台网的地震波数据,采用地震背景噪声互相关方法反演研究区域2~40 s瑞利波群速度和相速度分布,并进一步得出了该区域地壳的精细三维S波速度结构.反演成像结果显示,扬子块体与华夏块体的地壳及上地幔的结构特征差异显著.10~20 km的S波速度分布图显示呈线性的、连续分布低速异常,可能为扬子块体与华夏块体的具体分界位置.结合华南地区地球化学研究结果和构造历史,该低速异常可能代表了来自上地壳的变质沉积岩,即沉积岩受到上地幔物质上涌或底侵作用的加热变质形成.成像结果对了解华南地区的构造演化历史提供了地震学约束. 相似文献
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Q_β tomography under the crust and upper mantle in eastern China 总被引：2，自引：1，他引：1
IntroductionTheenergyattenuationofseismicwavesduringthepropagationcanbequantificationallydescribed.GeophysicistshavefoundoutthattheregionalvariationofoPisobviousandthevalueofoPatthestableregionisdistinctlyhigherthanthatatactiveregion(Canas,Mitchell,... 相似文献
14.
Remnants of Early Archaean rocks (>FX3000 m.y. old) are reported from most continents. A critical review of the radiometric data shows that few of these are well authenticated and most are very limited in extent. The oldest are predominantly plutonic gneisses of tonalitic-to-granitic composition (e.g., the basement gneisses of West Greenland, Labrador, Rhodesia and South Africa). In all cases there are inclusions of meta-volcanic and sedimentary rocks with greenstone belt affinities which probably represent crust into which the igneous parents of the gneisses were intruded.The trace element chemistry of these very old rocks is reviewed in an attempt to establish the mechanism of formation of early crust and place constraints on the chemical evolution of the earth's mantle. “Mantle-type” Sr isotope compositions show that the sialic members of both early gneisses and greenstone belts were not derived from much older crustal differentiates, either at 3800 or at 2800 m.y. ago. However, trace element ratios such as K/Rb and Sr/Ba, and rare earth element abundances, are not consistent with direct derivation of the plutonic suite from the upper mantle and also rule out a common parentage for the tonalites and granites. An origin by partial melting of metamorphosed juvenile crust with a composition range equivalent to that represented by the greenstone belts is preferred. Tonalites resulted from high-pressure melting of mafic garnet-amphibolite and at least some of the granites from low-pressure melting of more felsic (possibly even sedimentary) material.The trace element chemistry of the greenstone belt volcanics is thought to characterize the composition of early mantle melts, although the best preserved and best documented cases are about 500–1000 m.y. younger than the oldest known gneisses. The dominant type is tholeiite with low incompatible element contents and light-depleted or essentially flat rare earth patterns, features even more marked in the ultramafic komatiites which represent large degrees of melting. More evolved calc-alkaline rocks with relative incompatible and light rare earth element enrichment are also important. With the exception of the ultramafic lavas, all these types can be matched by the chemistry of present-day oceanic volcanism.It is concluded that the range of trace element variations in the earth's mantle was comparable in early Archaean times to that at the present. This is supported by mass balance calculations for the lithophile elements which have been preferentially extracted into the crust. Thus the isotope and trace element evidence of the oldest rocks argues against primary differentiation of the crust either during accretion of the earth or during its first 500 m.y. as a solid body. Crust formation has probably occurred continuously, although worldwide evidence for magmatism at around 2800 m.y. ago probably marks a particularly active period. 相似文献
15.
《Journal of Geodynamics》2007,43(1):87-100
The petrology and geochemistry of Icelandic basalts have been studied for more than a century. The results reveal that the Holocene basalts belong to three magma series: two sub-alkaline series (tholeiitic and transitional alkaline) and an alkali one. The alkali and the transitional basalts, which occupy the off-rift volcanic zones, are enriched in incompatible trace elements compared to the tholeiites, and have more radiogenic Sr, Pb and He isotope compositions. Compared to the tholeiites, they are most likely formed by partial melting of a lithologically heterogeneous mantle with higher proportions of melts derived from recycled oceanic crust in the form of garnet pyroxenites compared to the tholeiites. The tholeiitic basalts characterise the mid-Atlantic rift zone that transects the island, and their most enriched compositions and highest primordial (least radiogenic) He isotope signature are observed close to the centre of the presumed mantle plume. High-MgO basalts are found scattered along the rift zone and probably represent partial melting of refractory mantle already depleted of initial water-rich melts. Higher mantle temperature in the centre of the Iceland mantle plume explains the combination of higher magma productivity and diluted signatures of garnet pyroxenites in basalts from Central Iceland. A crustal component, derived from altered basalts, is evident in evolved tholeiites and indeed in most basalts; however, distinguishing between contamination by the present hydrothermally altered crust, and melting of recycled oceanic crust, remains non-trivial. Constraints from radiogenic isotope ratios suggest the presence of three principal mantle components beneath Iceland: a depleted upper mantle source, enriched mantle plume, and recycled oceanic crust.The study of glass inclusions in primitive phenocrysts is still in its infancy but already shows results unattainable by other methods. Such studies reveal the existence of mantle melts with highly variable compositions, such as calcium-rich melts and a low-18O mantle component, probably recycled oceanic crust. Future high-resolution seismic studies may help to identify and reveal the relative proportions of different lithologies in the mantle. 相似文献
16.
本文利用中国地震台网及ISC提供的区域地震和远震的P波走时数据,重建了中国大陆及其邻近地区的三维速度图象。 主要结果是:1.本文给出的速度图象揭示了中国大陆及其邻近地区的地壳和上地幔速度存在明显的横向不均匀性,这种不均匀性甚至在下地幔的1100km深度还依然存在。上地幔的速度图象同地表已知的地质构造特征的相关性可以追踪到110km,从220km以下很难找到它们之间的明显关系。2.45-0km和45+0km深度处的速度图象明显地表示出中国大陆的地壳厚度可以102.5°E附近为界分为两部分:其东部地壳薄,厚度都小于45km;西部有一条自若尔盖-松潘（34°N,102.5°E附近）向西北沿38°N往西至塔里木盆地南缘的分界线;其南部除滇西南之外,整个青藏高原的地壳厚度都大于45km;其北部除天山山脉之外,地壳厚度一般不大于45km.3.110km深度处的速度图象表明,速度异常呈块状分布。同中国大地构造分区略图比较之后发现,其中,扬子准地台和塔里木地台对应于高速区,中朝准地台则大都表现为低速异常;华南褶皱系为低速区,青藏地块南缘喜马拉雅和冈底斯念青唐古拉褶皱系则表现为高速异常。4.220km深度处的速度图象表明,中国大陆相当多的地区软流层有明显的显示。5.同450km和45+0km的速度图象一样,400km和600km的速度图 相似文献
17.
Abstract The Archean to Paleo–Proterozoic Bundelkhand massif basement of the central Indian shield has been dissected by numerous mafic dykes of Proterozoic age. These dykes are low‐Ti tholeiites, ranging in composition from subalkaline basalt through basaltic‐andesite to dacite. They are enriched in light rare earth elements (LREE), large ion lithophile elements (LILE) and depleted in high field strength elements (HFSE: Nb, P and Ti). Negative Sr anomaly is conspicuous. Nb/La ratios of the dykes are much lower compared with the primitive mantle, not much different from the average crustal values, but quite similar to those of continental and subduction related basaltic rocks. Bulk contamination of the mantle derived magma by crustal material is inadequate to explain the observed geochemical characteristics; instead contamination of the mantle/lithospheric source(s) via subduction of sediment is a better proposition. Thus, in addition to generating juvenile crust along the former island arcs, subduction processes appear to have influence on the development of enriched mantle/lithospheric source(s). The Bundelkhand massif basement is inferred to represent subduction related juvenile crust, that experienced lithospheric extension and rifting possibly in response to mantle plume activities. The latter probably supplied the required heat, material (fluids) and extensional environment to trigger melting in the refractory lithospheric source(s) and emplacement of the mafic dykes. Proterozoic mafic magmatic rocks from Bundelkhand, Aravalli, Singhbhum and Bastar regions of the Indian shield and those from the Garhwal region of the Lesser Himalaya display remarkably similar enriched incompatible trace elements characteristics, although limited chemical variations are observed in all these rocks. This may indicate the existence of a large magmatic province, different parts of which might have experienced similar petrogenetic processes and were probably derived from mantle/lithospheric source(s) with similar trace element characteristics. The minor, less enriched to depleted components of the Jharol Group of the Aravalli terrane and those from the Singhbhum terrane may represent protracted phases of rifting, that probably caused thinning and mobilization of the lithosphere, facilitating the eruption/emplacement of the asthenospheric melts (with N‐ to T‐types mid‐oceanic ridge basalts signatures) and deposition of deep water facies sediments in the younger developing oceanic basins. In contrast, Bundelkhand region did not experience such protracted rifting, although dyke swarms were emplaced and shallow water Bijawar Group and Vindhyan Supergroup sediments were deposited in continental rift basins. All these discrete Proterozoic terranes appear to have experienced similar petrogenetic processes, tectonomagmatic and possibly temporal evolution involving subduction processes, influencing the lithospheric source characteristics, followed by probably mantle plume induced ensialic rifting through to the development of oceanic basins in the Indian shield regions and their extension in the Lesser Himalaya. 相似文献
18.
华北地区拆离滑脱带控震作用初探 总被引：2，自引：0，他引：2
华北东部盆岭区以地震多、震级大、损失惨重而称。以往地震地质研究多注重断裂交汇、拐点、分枝等部位的控震作用。但是，华北盆岭区多次大震的烈度并不呈线型展布，震源也并非沿陡倾断裂走向分布，而是在一定深度上(近水平)弥散展布，故人们开始注意深部滑脱带控震的探讨。笔依据近十余年华北地幔亚热柱的研究认为，华北断陷区之下为—强烈上隆的地幔亚热柱。地幔物质的上隆及上侵作用使上地壳裂解断陷，而中地壳在地幔、下地壳的影响下形成相间展布的低速—高导层。在地幔亚热柱热物质流向外拆离的带动下，中、下地壳亦由亚热柱顶部向外围拆离滑脱。当中、下地壳拆离到上地壳裂陷盆地边缘受到造山带的阻挡而减慢时，两之间便产生剪切作用，导致应力不断积聚并阶段性释放，从而造成亚热柱外围地震频繁发生。 相似文献
19.
利用中国大陆东部及台湾地区、日本和琉球群岛的地震观测数据，通过体波地震层析技术反演了中国东部海域及其邻近地区的P波速度结构.以此为依据分析了不同地区的岩石层性质和深部动力学条件，探讨了中朝与扬子块体、扬子与华夏块体在海区的深部边界及其构造属性，揭示出菲律宾海板块与欧亚大陆的碰撞以及板片俯冲下沉、弧后扩张作用对中国东部海域岩石层结构的影响.结果表明，中国东部海域的岩石层地幔存在明显的横向非均匀性，它们与区域构造的形成演化有一定的联系.中国大陆东部的五莲－青岛断裂与朝鲜半岛西缘断裂、济州岛南缘断裂共同构成中朝和扬子块体的边界，江绍断裂向东延伸至朝鲜半岛南端成为分隔扬子和华夏块体的边界；东海陆架与冲绳海槽的岩石层结构差异明显，东海陆架具有中国东部地区的岩石层特征，属于欧亚大陆向海域的延伸；冲绳海槽的岩石层强烈减薄，为大陆向大洋过渡的区域；沿着日本－琉球－台湾俯冲带，菲律宾海板块俯冲下沉引起的地幔扰动对中国东部海域产生了较大的影响，欧亚大陆与菲律宾海板块之间的相互碰撞导致台湾地区岩石层明显增厚. 相似文献
20.
On the basis of data of long period Rayleigh surface wave, we select 43 two-station paths which cover the eastern China thoroughly. By using the improved method of multi-filtration, we obtain the group velocity and amplitude spectrum, and then get attenuation factor for each paths. We employ Talentola inversion method to get local attenuation factor, and further invert the three-dimension Q β image under the crust and upper mantle in the eastern Chinese continent. The Q β image shows the following basic characters. There is correlation between the seismic activity and Q β structure under the crust and upper mantle in North China region. The Yangtze block begins to collide with and subduct to the North China block from the southern border of the Qinling in the southern Shaanxi. In the large part of Yangtze quasi-platform appear an obvious high Q β area at 88 km deep. In the east of Sichuan depression platform, the juncture of Sichun and Guizhou, and the Jiangnan block near the juncture of Guizhou and Hunan, the lateral variation of Q β in the crust is little, and there is a high-Q β layer no thinner than 40 km in the top mantle. In the Dian-Qian fold and fracture region between Yunnan and Guizhou, the vertical variation of Q β at the region of the crust and upper mantle is little, there is a low-Q β layer in the top mantle, about 40 km thick, low-Q β layer of the upper mantle begins to appear at about 95 km deep. In the east of Yangtze quasi-platform and the central and eastern part of the South China fold system, the Moho is smooth, the lateral variation of Q β in the crust is also little, low-Q β layer of the upper mantle begins to appear at about 85 km deep. 相似文献