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辽河盆地与伸展作用有关的构造动力学分析 总被引：1，自引：1，他引：0
辽河盆地是中生代大陆的裂谷盆地,以伸展作用为主,同时受到后期走滑作用的改造,构造形式复杂,裂谷盆地的形成,演化是在伸展活动发生复杂而有规律的运动中进行的,表现为水平伸展运动,垂直升降运动,掀斜或翘倾运动等,这是裂谷盆地的主要特征。 相似文献
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利用板块构造理论,依据近年来1：5万区域地质调查及相关科研成果,对辽宁地壳发展演化进行了分析研究,提出辽宁地壳发展可暂划分为早前寒武纪大陆增生构造体制和中元古宙以来的板块构造体制.中太古代-古元古代发现了绿岩地体和古元古宙裂谷,因此将早前寒武纪视作原始板块,中元古代-古生代视作古板块,中生代以来视作现代板块.在此基础上对辽宁大地构造单元进行了划分.辽宁Ⅰ级构造单元为塔里木-华北板块.Ⅱ级构造单元为天山-赤峰陆缘活动带和华北陆块.Ⅲ级构造单元5个,分别为建平-西丰华力西陆缘造山带、冀辽地块、铁岭-清原微地块、辽吉地块及下辽河-辽东湾新生代裂谷.Ⅳ级构造单元16个.为清楚地了解辽宁地壳发展演化特点,对5个Ⅲ级构造单元地质特征进行简要阐述. 相似文献
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本文论述了辽东早元古代沉积盆地是一个大陆型—陆间型裂谷,分析了裂谷的地质构造特征及其演化历史。作者认为辽东裂谷的发生、发展与古郯庐断裂的活动有密切关系,裂谷在空间上分异为三个构造岩相区,其发展是多旋回的,早、晚二期旋回均经历了自拉张裂陷—挤压、隆升的过程,早期旋回形成的建造为辽阳群,晚期旋回堆积了辽河群,裂谷于1700±100Ma时封闭。 相似文献
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辽河外围西部发育了一系列晚中生代陆相沉积盆地。它们经历了前裂谷盆地期、同裂谷盆地期、后裂谷盆地期,以及盆地形成后的改造期四个阶段。在裂谷体制作用下,它们形成了相似的断陷构造样式。但基底结构的基异产生了盆地沉积建造与后裂谷阶段的重大差异。盆地盖层的发育主要决定于后者,因此在裂谷型盆地的油气成藏条件及其演化发带与成块特征。 相似文献
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辽宁营口东部白硼矿床特征及找矿方向 总被引：1，自引：0，他引：1
辽宁省营口东部是我国白硼矿床重要产区之一。白硼矿床赋存在早元古宙辽东裂谷带内。辽河群里尔峪岩组,黑云变粒岩、电气变粒岩夹含硼镁橄岩为含硼岩系。东西向、北西向断裂带为储矿构造,辽河期复式深成黑云母二长花岗岩为其成矿母岩（热源体）。蛇纹石化大理岩、蛇纹石化镁橄岩是重要的含硼蚀变岩带及找矿标志。 相似文献
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在辽东－吉南地区存在两个性质不同的变质地体：辽北地体和辽南地体,二者之间以断裂带或韧性剪切带相接。辽北地体包括北辽河群和老岭群,辽南地体包括南辽河群和集安群。不同变质地体内的早元古代变质岩系在地层系统及岩石组合、原岩建造及沉积环境、变质作用类型及ｐＴｔ轨迹、区域构造和岩浆活动等方面都存在明显的差别。它们在早元古代时期形成于不同的大陆边缘,具有完全不同的形成条件和演化历史。两个变质地体最晚在早元古代晚期经构造作用拼贴在一起。 相似文献
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专家们对华北陆台早前寒武纪基底构造格局形成与演化的认识既有共同点又有分歧。共同点是太古宙为形成刚性小陆块的时期 ,其成因可能与地幔柱的垂直增生有关 ,如TTG质岩类的大量增生与侵位。小陆块的构造拼合形成华北克拉通的主体。分歧焦点是陆块拼合的时代 :第一种认为小陆块的拼合发生在新太古代 ,即华北陆台在新太古代就已克拉通化 ,到古元古代时在伸展构造体制作用下 ,形成了一系列的裂谷或拗拉谷。第二种认为拼合发生在古元古代 ,即华北陆台是吕梁运动才克拉通化的。形成裂谷或拗拉谷的时期在中元古代 相似文献
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东海陆架盆地地质结构及构造演化 总被引：11，自引：0，他引：11
东海陆架盆地发育于东海大陆架之上,是一个复合型沉积盆地。盆地的西侧是浙闽隆褶带,东侧是钓鱼岛岩浆岩带,盆地从西至东呈现为凹-凸-凹的格局,南北差异明显,总体地质构造格架表现为东西分带、南北分块的特征。该盆地存在元古代的变质基底,是浙闽沿海陆区出露的深变质岩系向东的延伸,这套古老的变质岩系组成了陆架盆地的主要基底。盆地在垂向上表现为明显的多层结构。除古生界地质结构尚待证实外,中生界明显为裂谷型二层结构,新生界为三层结构。盆地结相特征受控于特定的构造演化过程。中生代以前不同性质的地体增生和中生代以来太平洋板块的运动方向不断变化以及印度板块作用造成的地壳蠕散是控制盆地形成和树造演化的主要体制,使盆地构造演化表现为多阶段、多种构造体的明显特征。 相似文献
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Kurosegawa Terrane in Southwest Japan: Disrupted Remnants of a Gondwana-Derived Terrane 总被引：1，自引：0，他引：1
The Kurosegawa Terrane is an anomalous, disrupted, Paleozoic and Mesozoic lithotectonic assemblage characterized by fragments of continent and continental margins. It is located in Southwest Japan where it lies between two Mesozoic subduction complex terranes. The Kurosegawa Terrane is an exotic and far-travelled geologic entity with respect to its present position. Limestones of the Kurosegawa Terrane formed along a continental margin yield fusulinacean fossils Cancellina, Colania and Lepidolina. Accordingly, the Kurosegawa Terrane was once situated within the Colania-Lepidolina territory in the East Tethys-Panthalassa region at a palaeo-equatorial latitude, possibly close to the eastern margin of the South China and/or Indochina-East Malaya continental blocks. These blocks had rifted from Gondwana by late Devonian. They drifted northwards, passing through the Colania-Lepidolina territory in mid-Permian time, and amalgamated with the proto-Asian continent during the late Triassic. Subsequently, during the Cretaceous, parts of the allochthonous continental blocks and their associated tectonic collage were transpressed, dispersed, and displaced from the southeastern periphery of Asia towards the north. As a result, the Kurosegawa Terrane is formed as a disrupted allochthonous terrane, characterized by a serpentinite melange zone, lying between the adjoining Mesozoic subduction complex terranes. 相似文献
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Rocks of the west flank of the northern Appalachian Orogen (miogeocline) record the history of the late Precambrian-early Paleozoic passive continental margin of Eastern North America. The ancient margin was destroyed by ophiolite obduction and arc collision during the Ordovician Taconic Orogeny. The present sinuous form of the miogeocline is interpreted to reflect ancient promontories and re-entrants of a previous orthogonal margin bounded by rifts and transforms.Four major terranes are recognized east of the miogeocline in Newfoundland and Nova Scotia. From west to east, these are the Dunnage, Gander, Avalon and Meguma. The Dunnage and Gander terranes were linked to the miogeocline during the Middle Ordovician Taconian Orogeny. The Avalon terrane arrived later, possibly during the mid-Paleozoic Acadian Orogeny. The Meguma terrane of southern Nova Scotia had docked with the Avalon terrane by Carboniferous time. The Dunnage terrane contains arc volcanics which lie above an ophiolitic substrate. The Gander terrane comprises a thick sequence of clastic sedimentary rocks, underlain by basement rocks with continental affinities. It has been interpreted as a continental margin, perhaps once on the eastern side of the Paleozoic Iapetus ocean. The Avalon terrane consists of belts of sedimentary and volcanic rocks which are probably underlain by Grenvillian basement. Its tectonic affinities are unclear. The Meguma terrane comprises a thick sequence of sediments, derived from the south-east. It is found only in southeastern Atlantic Canada. The boundaries between terranes are compressional in the west and steep, transcurrent faults in the east.The surface extent of the geological terranes is grossly correlative with deep structural zones, although no direct evidence exists for linking the two because most surface structures can be traced geophysically to only a few kilometres depth. A striking feature of the deep crustal structure is a lower, high velocity crustal layer beneath the Dunnage and Gander terranes.The modern margin of Atlantic Canada developed by rifting and by transform motion between adjacent continents. Stretching and thinning of the lithosphere, and the consequent production of basaltic magma that in places intrudes or underplates the thinned continental crust, are the most likely processes responsible for the evolution of the modern margin. These processes predict the observed deep sedimentary basins along the margin, the thinning of continental crust, and the high seismic velocities found within the ocean-continent transition zones.Rifting adjacent to Nova Scotia began in Late Triassic-Early Jurassic time between the present African and North American plates. These plate motions are also responsible for the major transform margin south of the Grand Banks. Separation between Iberia and the eastern Grand Banks occurred in mid-Cretaceous time, before the Late Cretaceous opening of the Labrador Sea. While the rifted segments of the margin exhibit deep sedimentary basins and thinned continental crust, the Grand Banks transform segment is characterized by a sharp transition zone and a relatively thin sediment cover. Numerous volcanic seamounts are built on the ocean crust adjacent to this transform segment.Mimicry of Paleozoic promontories and re-entrants by modern rift and transform margin segments, the location of Mesozoic sedimentary basins on ancestral Appalachian structures, and the reactivation and propagation of major Precambrian and Paleozoic structural boundaries during the latest phase of ocean opening attest to ancestral controls of the modern margins.The rift phase of both the ancient and modern passive margins is characterized by volcanism, mafic dike intrusion and by the development of basins filled with clastic sediments. The drift phase of both the ancient margin and the present Nova Scotia margin is marked by a change in sedimentary environment, such that carbonates replaced the rift phase clastic sediments. Two of the markers used to delineate the ancient ocean-continent transition zone; carbonate banks and steep gravity anomaly gradients, should be used with caution as the modern analogs of these markers may lie 100 km or more of this transition zone. Furthermore, it is naive to view the ancient transition as simple and narrow, for the modern margins exhibits complex transition zones between 30 and 300 km wide.In general, the evolution of the ancient and modern passive margins appear to be remarkably similar. Predictably, closing the present Atlantic will mimic the evolution of the Appalachian Orogen. 相似文献
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The continental margin north of Alaska, as interpreted from seismic reflection profiles, is of the Atlantic type and consists of three sectors of contrasting structure and stratigraphy. The Chukchi sector, on the west, is characterized by the deep late Mesozoic and Tertiary North Chukchi basin and the Chukchi Continental Borderland. The Barrow sector of central northern Alaska is characterized by the Barrow arch and a moderately thick continental terrace build of Albian to Tertiary clastic sediment. The terrace sedimentary prism is underlain by lower Paleozoic metasedimentary rocks. The Barter Island sector of northeastern Alaska and Yukon Territory is inferred to contain a very thick prism of Jurassic, Cretaceous and Tertiary marine and nonmarine clastic sediment. Its structure is dominated by a local deep Tertiary depocenter and two regional structural arches.We postulate that the distinguishing characteristics of the three sectors are inherited from the configuration of the rift that separated arctic Alaska from the Canadian Arctic Archipelago relative to old pre-rift highlands, which were clastic sediment sources. Where the rift lay relatively close to northern Alaska, in the Chukchi and Barter Island sectors, and locally separated Alaska from the old source terranes, thick late Mesozoic and Tertiary sedimentary prisms extend farther south beneath the continental shelf than in the intervening Barrow sector. The boundary between the Chukchi and Barrow sectors is relatively well defined by geophysical data, but the boundary between the Barrow and Barter Island sectors can only be inferred from the distribution and thickness of Jurassic and Cretaceous sedimentary rocks. These boundaries may be extensions of oceanic fracture zones related to the rifting that is postulated to have opened the Canada Basin, probably beginning during the Early Jurassic. 相似文献
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中生代东亚大陆边缘构造演化 总被引：18，自引：2，他引：16
摘 要 根据东亚陆缘增生带生物古地理、放射虫时代研究的进展并结合同位素年代及东亚
地区火山活动、构造演化探讨了中生代东亚大陆与古太平洋板块之间的运动学关系及俯冲带
后退特征。中、晚三叠世那丹哈达岭、美浓等地体还位于北纬１２°以内及赤道附近,晚侏罗世
到达中高纬度。东亚活动大陆边缘开始于中侏罗世末,在此之前属转换大陆边缘。洋壳板块
向大陆下俯冲之后,由于地体拼贴引起俯冲带快速、长距离后退。 相似文献
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在对太原掀斜构造形迹分析的基础上,通过节理统计,以板块构造和大陆动力学理论为基础,研究了古构造应力场特征和构造演化历程。结果表明:太原掀斜构造由东山背斜、西山向斜和太原断陷组成。中生代以来的构造演化可分为中生代晚期、古近纪及新生代晚期三个阶段。主体构造,即东山背斜、西山向斜以及相伴生的南北向褶曲等都是在中生代晚期北东—南西向右旋力偶作用下形成。区内等距分布的北东东向至东西向的正断层组等次级构造及太原断陷的雏形形成于古近纪北东—南西向左旋力偶。在新生代晚期北西—南东向拉张应力作用下,太原断陷进一步拉张下陷,形成现今构造格局。不同时期应力场和板块构造动力系统不尽相同,但它们之间有继承的特点,其形成演化与区域大陆动力学条件转化和演化一致。 相似文献
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下辽河裂谷是我国东部规模巨大的郯庐断裂带的一部分。五十年代以来,地质和地球物理工作者对郯庐断裂带进行过大量的专题和综合性研究[1-5],取得了可喜的进展。尽管如此,目前对其形成时代、延伸规模、力学机制及活动方式等重要问题,尚存在分歧意见。已有资料表明,发育在华北断块区内的一段,应是郯庐断裂带的主体部分,已确信无疑。该段东界的主干断裂,可能形成于太古代末期(其它三条主干断裂形成时代可能稍晚,但至少在中生代即已存在),构成胶辽断块与冀鲁断块的边界。长期以来,它控制着两侧断块基底的形成和古生界盖层的发育,以及构造格架的布局。 相似文献