Structural architecture of Neoproterozoic rifting depression groups in the Tarim Basin and their formation dynamics   总被引：1，自引：0，他引：1  

Bizhu HE  Cunli JIAO  Taizhu HUANG  Xingui ZHOU  Zhihui CAI  Zicheng CAO  Zhongzheng JIANG  Junwen CUI  Zhuoyin YU  Weiwei CHEN  Ruohan LIU  Xiaorui YUN  Guangming HAO 《中国科学:地球科学(英文版)》2019,(3):529-549

The Tarim Basin is the largest, oil-bearing, superimposed basin in the northwest of China. The evolution and tectonic properties of the initial Tarim Basin have been hotly disputed and remain enigmatic. The Neoproterozoic basin is covered by a vast desert and a huge-thickness of sedimentary strata, has experienced multiple tectonic movements, had a low signal to noise ratios(SNRs) of deep seismic reflection data, all of which have posed critical obstacles to research. We analysed four field outcrops, 18 wells distributed throughout the basin, 27 reprocessed seismic reflection profiles with higher SNRs across the basin and many ancillary local 2D and 3D profiles and aeromagnetic data. We found about 20 normal fault-controlled rifting depressions of the Cryogenian and Ediacaran scattered throughout the basin, which developed on the Precambrian metamorphic and crystalline basement. The structural framework is clearly different from that of the overlying Phanerozoic. The rifting depressions consist of mainly half grabens, symmetrical troughs and horst-grabens. From the northeast to southwest of the basin,they are divided into three rifting depression groups with the WNW, ENE, and NW-trends that are mainly controlled by normal faults. The maximum thicknesses of the strata are up to 4100 m. From the Cryogenian to Ediacaran, most of the main inherited faults to active and eventually ceased at the end of the Ediacaran or Early Cambrian, while subsidence centres appeared and migrated eastward along the faults. They revealed that the different parts of the Tarim continental block were in NNE-SSWoriented and NNW-SSE-oriented extensional paleo-stress fields(relative to the present) during the Neoproterozoic, and were accompanied by clockwise shearing. According to the analysis of the activities of syn-sedimentary faults, filling sediments,magmatic events, and coordination with aeromagnetic anomalies, the tectonic properties of the fault depressions are different and are primarily continental rifts or intra-continental fault-controlled basins. The rifting phases mainly occurred from 0.8–0.61 Ga.The formation of the rifting depression was associated with the initial opening of the South Altun-West Kunlun Ocean and the South Tianshan Ocean, which were located at the northern and southern margins of the Tarim Block, respectively, in response to the break-up of the Supercontinent Rodinia and the initial opening of the Proto-Tethys Ocean.  相似文献   

山西地区远震P波到时残差分布     

石磊  李凤  刘静  韩文英 《地震地磁观测与研究》2019,40(1):43-47

收集2008—2016年山西地震台网记录的震中距30°—90°范围内1 253个远震事件波形,拾取7 600余条高质量P波初至到时,使用IASP91模型计算相对到时残差,分析残差水平分布特征,结果显示:①以山西地区中部的山西断裂带为界,西部地震台站记录的P波初至主要表现为早到时,东部位于大同火山区的地震台站记录则主要表现为晚到时;②位于山西断裂带内部的地震台站记录的P波初至主要表现为早到时,残差水平显著低于西部地震台站;③研究区P波到时整体呈现自西向东逐渐由早到晚的分布特征。推测山西断裂带西部地区下方可能存在高速异常结构,山西断裂带内部及大同火山区下方可能存在低速异常结构。  相似文献   

东海盆地中、新生代盆架结构与构造演化   总被引：6，自引：0，他引：6  

刘金水  许怀智  蒋一鸣  王军  何新建 《地质学报》2020,94(3):675-691

基于地貌、钻井、岩石测年和地震等资料,分析盆地地层分布、盆架结构、构造单元划分和裂陷迁移规律,结果表明东海盆地由台北坳陷、舟山隆起、浙东坳陷、钓鱼岛隆褶带和冲绳坳陷构成,是以新生代沉积为主、中生代沉积为辅的大型中、新生代叠合含油气盆地;古元古代变质岩系构成了盆地的基底。该盆地不仅是印度-太平洋前后相继的动力体系作用下形成的西太平洋沟-弧-盆构造体系域一部分,而且也是古亚洲洋动力体系作用下形成的古亚洲洋构造域和特提斯洋动力体系作用下形成的特提斯洋构造域一部分,晚侏罗世至早白垩世经历了构造体制转换,盆地格局发生重大变革,早白垩世以前主要受古亚洲-特提斯洋构造体制影响的强烈挤压造山和地壳增厚作用演变为早白垩世以来主要受太平洋构造体制控制的陆缘伸展裂陷和岩石圈减薄作用,经历侏罗纪古亚洲-特提斯构造体制大陆边缘拗陷和白垩纪以来太平洋构造体制弧后裂陷两大演化阶段。白垩纪以来太平洋构造体制的弧后裂陷演化阶段可细分为早白垩世至始新世裂陷期、渐新世至晚中新世拗陷期和中新世末至全新世裂陷期。  相似文献   

Tectonostratigraphy and sedimentary architecture of rift basins, with reference to the northern North Sea     

A. Nottvedt  R.H. Gabrielsen  R.J. Steel 《Marine and Petroleum Geology》1995,12(8)

A tectonostratigraphic model for the evolution of rift basins has been built, involving three distinct stages of basin development separated by key unconformities or unconformity complexes. The architecture and signature of the sediment infill for each stage are discussed, with reference to the northern North Sea palaeorift system. The proto-rift stage describes the rift onset with either doming or flexural subsidence. In the case of early doming, a proto-rift unconformity separates this stage from the subsequent main rift stage. Active stretching and rotation of fault blocks during the rift stage is terminated by the development of the syn-rift unconformity. Where crustal separation is accomplished, a break-up unconformity commonly marks the boundary to the overlying thermal relaxation or post-rift stage. Tabular architectures, thickening across relatively steep faults, characterize the proto-rift stage. Syn-rift architectures are much more variable. Depending on the ability of the sediment supply to fill the waxing and waning accommodation created during rotation and subsidence, one-, two- or three-fold lithosome architectures are likely to develop. During the post-rift stage, an early phase with coarse clastic infilling of remnant rift topography often precedes late stage widening of the basin and filling with fine-grained sediments.  相似文献   

Gravity and magnetic field characteristics and regional ore prospecting of the Yili ancient continent,West Tianshan,Xinjiang Uygur Autonomous Region,China     

《China Geology》2020,3(1):104-112

Gold, iron, copper, lead-zinc and other mineral exploration in West Tianshan, Xinjiang Uygur Autonomous Region, has made remarkable progress in recent years. However, due to the dispute on the tectonic division of West Tianshan, the ore-controlling factors and the regional metallogenic laws are controversial. The authors analyze regional gravity data and notice that the high-value region corresponds to the Yili ancient continent, thus the southeastern boundary of the Yili ancient continent is delineated. Comparative analysis of gravity, aeromagnetic and geologic data reveals that the Tulasu basin, where some medium to large epithermal gold deposits locate, lies above the Yili ancient continent; the Yili Carboniferous-Permian rift extends in E-W direction, numbers of copper deposits have been found in the mid-west section of the rift which lies above the Yili ancient continent, whereas few copper deposits have been discovered in the east section which is outside the Yili ancient continent. Accordingly, the Yili ancient continent may he rich in gold, copper and other metal elements; the metal-bearing hydrothermal solution moves up with the activity of magmatism, and deposits in the favorable places (the Tulasu basin and the Yili Carboniferous-Permian rift), forming numerous small and medium gold, copper deposits, as well as some large and super-large gold deposits. Therefore, the tectonic-magmatic hydrothermal zone above the Yili ancient continent should be the prospective area for epithermal gold and copper polymetallic deposits.  相似文献   

Evolution of drainage,sediment-flux and fluvio-deltaic sedimentary systems response in hanging wall depocentres in evolving non-marine rift basins: Paleogene of Raoyang Sag,Bohai Bay Basin,China     

Hehe Chen  Xiaomin Zhu  Lesli J. Wood  Ruisheng Shi 《Basin Research》2020,32(1):116-145

The dynamics of sediment feeding into rift basins and the geomorphologic nature of source areas are critical elements in understanding the evolution of rifted basins. This study integrates seismic, well and geochronologic data on the western dipslope of the Raoyang Sag, a rift associated sub-basin to the larger Bohai Bay Basin of China to define the history of drainage development for the basin and to assess the sedimentologic response to drainage evolution events. In the Paleogene-age Lixian Slope, as indicated by paleo-drainage configuration, progradational seismic geometries, compositional maturity and zircon-tourmaline-rutile maturity index trends, three drainages; the paleo-Daqing River, paleo-Tang River and paleo-Dasha River drainages were feeding three closely spaced hanging wall deltaic depositional systems; Delta A fed from the northwest, Delta B fed from the west and Delta C fed from the southwest, respectively. From the late Eocene to early Oligocene, a decrease in sediment-flux into the hanging wall is documented and petrographic analysis is used to link these changes to stream-capture in the upstream catchment of the Daqing River. This change is coupled with morphologic changes in the geometries of Deltas A and C, both of which show decreasing deltaic areas, changes in lobe geometry and changes in distributary channel sizes. In addition, the progradational direction of Delta C changes from perpendicular-to-the-rift axis to prograding oblique-to-the-rift axis. It is apparent that the progradation and retrogradational changes in rift margin deltas do not happen in isolation, but such changes can affect growth and progradation direction in adjacent deltas. This work shows that the decrease in sediment-flux, caused by a drainage capture, will result in a decrease in distributary channel size and delta size and may result in upstream deltas taking advantage of such decreasing confinement to prograde more obliquely to the rift axis.  相似文献   

博罗霍洛褶断带大地构造演化特征     

宁晰春 《地球科学与环境学报》1996,(2)

研究区属中天山褶皱断裂隆起带的一部分，北邻准噶尔阿拉套晚古生代岛弧，南毗伊犁地块。博罗霍洛褶断带的发展演化与天山造山带密切相关，它的雏型可追溯到晚元古代已展现出东西向隆起带，早古生代成为大陆裂谷，到晚古生代随着天山地槽的封闭开始褶皱隆起，中新生代以升降运动为主，造成强烈的构造复活并产生大量新断裂。  相似文献   

Myojin Rift, Izu–Bonin Arc as the Modern Analog of Hokuroku Basin, Northeast Japan: Geotectonic Significance of the New Hydrothermal Deposit in the Back-Arc Rift     

Michio Tanahashi    Kantaro Fujioka  Shiki Machida 《Resource Geology》2008,58(3):301-312

A huge hydrothermal field, named the "Hakurei Sulfide Deposit" (HSD) was discovered in the North Myojin Rift (NMR), Izu–Bonin Back-Arc Rift (BAR) during the 2003 survey cruise of R/V Hakurei-maru No.2 . This paper investigates the geotectonic features and the tectonic setting of ore deposits between the NMR and the Hokuroku Basin, which is representative of kuroko fields in Japan. The topographic features of the NMR and the Hokuroku Basin are similar. Both have a clear ring structure surrounded by faults and the east–west width is almost the same. Many kuroko deposits were formed on the extrusion centers of the five pre-mineral acidic volcanic complexes, located in a loop inside the Hokuroku Basin. In the case of the NMR, seven submarine volcanoes are also located in a loop, and the HSD formed inside the summit caldera of Bayonnaise Knoll, which is one of the seven volcanoes. These topographic similarities highlight that the NMR is a modern analog of the Hokuroku Basin. Identifying such similarities is extremely useful when prospecting kuroko deposits on land equivalents as well as on the other segments of the Izu–Bonin BAR. The probability of finding kuroko deposits on land is expected to increase when the following are identified: (i) location of back-arc rift and the volcanic front; (ii) direction of the arc–trench system and intra-rift faults (and/or fracture zone); (iii) position of submarine volcanoes surrounding a back-arc rift; and (iv) intersections of a caldera fault and intra-rift fault (and/or fracture zone) inside the summit caldera of submarine volcanoes. Within these aforementioned points a ring structure, acidic volcanic complexes that circle the circuit and submarine calderas along the volcanic front, are an important indication of submarine hydrothermal deposits.  相似文献   

煤层断裂模式及形成机制的研究     

赵理中  曾凡桂 《华北地质矿产杂志》1997,12(2):156-161

本文以山西省汾西矿区崔家淘井田断层构造的展布规律、断层面构造岩特征民层滑动擦痕为依据，分析断层发育的力学机制衣成生欠，应用赤平投影图矿区两条主干断层，得出 区三向主支应力轴方向的认识，提出一种在华北地区有代表性煤矿区展布模式芝对断层的识别和预测具有指导意义。  相似文献   

陕西秦巴火山岩的分布特征及其与成矿的关系   总被引：1，自引：0，他引：1  

王清廉 《陕西地质》1992,(2)

陕西秦巴区元古宙和早古生代火山活动强烈,火山岩发育。经研究,其火山岩形成机制,多与裂谷构造有关。这些火山岩中与之相关的矿产有钼、铼、钨、金、铅、银、锌、铜、铁、金红石及有关的非金属矿等。本文从该区火山岩的特征出发,分析其所产出的大地构造环境,并探讨火山岩与矿产之间的关系,最后提出进一步找矿的建议。  相似文献