排序方式： 共有27条查询结果，搜索用时 15 毫秒
1.
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)
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
2.
3.
An increasing impervious area is quickly extending over the Wu‐Tu watershed due to the endless demands of the people. Generally, impervious paving is a major result of urbanization and more recently has had the potential to produce more enormous flood disasters than those of the past. In this study, 40 available rainfall–runoff events were chosen to calibrate the applicable parameters of the models and to determine the relationships between the impervious surfaces and the calibrated parameters. Model inputs came from the outcomes of the block kriging method and the non‐linear programming method. In the optimal process, the shuffled complex evolution method and three criteria were applied to compare the observed and simulated hydrographs. The tendencies of the variations of the parameters with their corresponding imperviousness were established through regression analysis. Ten cases were used to examine the established equations of the parameters and impervious covers. Finally, the design flood routines of various return periods were furnished through use of approaches containing a design storm, block kriging, the SCS model, and a rainfall‐runoff model with established functional relationships. These simulated flood hydrographs were used to compare and understand the past, present, and future hydrological conditions of the watershed studied. In the research results, the time to peak of flood hydrographs for various storms was diminished approximately from 11 h to 6 h in different decrements, whereas peak flow increased respectively from 127 m3 s?1 to 629 m3 s?1 for different storm intensities. In addition, this study provides a design diagram for the peak flow ratio to help engineers and designers to construct hydraulic structures efficiently and prevent possible damage to human life and property. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
4.
5.
西藏波龙斑岩铜金矿床成矿斑岩年代学、岩石化学特征及其成矿意义 总被引：12，自引：0，他引：12
波龙斑岩铜金矿床是近年来在青藏高原中部发现的最大的斑岩型矿床,波龙矿床发育两期花岗闪长斑岩和一期花岗斑岩,两期花岗闪长斑岩是波龙矿床的成矿斑岩。本文开展了波龙矿床三期斑岩锆石U-Pb年龄、全岩岩石地球化学和Sr-Nd-Hf同位素组成分析。锆石U-Pb测年结果显示,三期斑岩在120Ma集中侵位。两期花岗闪长斑岩均富集轻稀土、大离子亲石元素,亏损重稀土、高场强元素,Eu异常不明显,显示出岛弧岩浆岩的特征;两期花岗闪长斑岩的(87Sr/86Sr)i值分别为0.70562－0.70711和0.70567－0.70850,εNd(t)分别为-4.0－-3.1和-8.0－-2.4,εHf(t)值分别变化于2.5－6.9和3.3－6.9,表明两期花岗闪长斑岩起源于新生的下地壳;花岗斑岩也具有岛弧岩浆岩的岩石化学特征,但其具有较高εNd(t)值(-0.7－-0.2)和εHf(t)值(1.3－12.2),可能表明花岗斑岩也起源于下地壳,但有更多幔源物质混入。波龙斑岩铜金矿床形成于班公湖－怒江洋壳向北俯冲末期,其成岩－成矿可能与洋壳俯冲关系密切,但波龙矿床的三期斑岩均起源于新生的下地壳,可能表明在120Ma南羌塘地块南缘开始逐步加厚。 相似文献
6.
FY-3B TOU臭氧总量产品空间分辨率为50 km,在开展小区域或精细化的臭氧研究时,需要获得更高分辨率、更具有准确和可靠性的臭氧插值数据。常规的数据插值方法没有考虑TOU臭氧总量受短波辐射、海拔高度的影响,所得到的插值数据参考性不强。文中介绍TOU多元回归插值方法,方法采用程序设计方式,动态分析TOU与短波辐射、海拔高度之间的相关性,建立一元回归模型,并根据一元回归模型结构建立多元回归模型,再通过多元回归模型对TOU进行插值。使用OMI臭氧总量数据对插值结果开展验证,验证结果表明采用多元回归算法的插值具有较好的可行性。且该插值方法及程序设计对其他类似的数据插值、分析具有一定的借鉴和参考意义。 相似文献
7.
塔里木盆地塔河地区海西晚期火山岩构造特征与油气成藏 总被引：1，自引：0，他引：1
通过地震剖面解释,根据断裂的切割层位将研究区火山岩断裂分为3类,即深层断裂、浅层断裂、火山岩内部微断裂。通过编制这3类断裂的平面展布图,对塔河地区火山岩断裂的性质、形成期次、分布特征及形成机理进行了分析。认为深层断裂形成于加里东期-海西期,以逆冲断层为主,走向呈NNE、NE、NNW3组,断裂主要分布于塔河火山岩发育区北部、西北部。浅层断裂形成于燕山期-喜马拉雅期,以正断层为主,断裂走向呈NE、NNE向,主要分布于盐边地带和东南部盐上火山岩分布区。火山岩内部的微断裂在顶部较底部发育,主要分布于塔河地区西部的火山岩中。根据火山岩储层和构造成因类型,将塔河地区火山岩划分为3种圈闭类型,即:构造裂缝和淋滤风化共同控制的圈闭、古凸起不整合遮挡和抬升淋滤风化共同控制的圈闭、埋藏溶蚀和构造裂缝共同控制的圈闭。分析了火山岩圈闭顶部的盖层条件和火山岩的油气成藏条件,认为三叠系底部柯吐尔组泥岩可形成有效的区域性封盖,塔河地区火山岩具有良好的油气成藏条件。 相似文献
8.
9.
雷州半岛硅藻土煅烧中的结构变化 总被引：5，自引：4，他引：5
本文应用Ｘ射线衍射、红外光谱、扫描电镜等手段，对广东海康、徐闻的硅藻土在煅烧过程中热结构变化进行了探讨。结构表明，煅烧使硅藻内部矿物的微观结构发生变化而引起形变，主要为ＳｉＯ２从无序含水的蛋白石转变为有序的方石英晶体。形变温度随其硅藻的种类和杂质不同而各异。本研究为这两地硅藻土的开发提供了科学依据。 相似文献
10.
华北地区晚中生代重大构造转折的地质证据 总被引：9，自引：3，他引：6
华北地区在侏罗纪和白垩纪分别发生了两次不同性质的岩浆活动,早期形成一套高锶石英闪长岩,另一期为钾玄岩系。两套岩石分别代表地壳加厚和减薄的构造背景,两次岩浆活动的转折期大致在130Ma左右,此外,华北地区自垩纪广泛分布的碱性岩同样表明区域内在白垩纪曾发生过强烈的岩石圈伸展作用。这一地质特征与区内盆地地震剖面、造山带构造活动年龄、变质核杂岩的年龄、早向坚世太平洋板块运动方向和运动速率的改变以及郯庐断裂左旋运动年龄等地质资料相佐证。因此华北地区岩石圈减薄作用主要发生在早向垩世时期,晚侏罗世——早白垩世是华北地区中生代重大构造发生的转折点。 相似文献