1985年新疆乌恰地震烈度与发震构造   总被引：5，自引：0，他引：5  

冯先岳 《内陆地震》1999,13(2):169-178

１９８５年乌恰地震发生在新疆乌恰县城东南４０ｋｍ的克孜勒苏河谷中。震中烈度为Ⅸ度,地震类型为主震－余震型,余震具有波伏衰减的特征。乌恰县城和乌帕尔镇大多数房屋倒塌或遭到破坏。主震在极震区内克孜勒苏河谷阶地上产生了一条地表破裂带,其长为１５ｋｍ,宽为１００￣８００ｍ,由地震断层、挤压脊和地震裂缝组成。１９９５年乌恰地震的发震构造是卡兹克阿尔特逆掩断裂。该地震应属褶皱类型地震,这类地震产生的震害具有上  相似文献   

Dynamic monitoring the infrastructure of major ports in Sri Lanka by using multi-temporal high spatial resolution remote sensing images     

Yong Ge  Yuehong Chen  Yuanxin Jia  Xian Guo  Shan Hu 《地理学报(英文版)》2018,28(7):973-984

Colombo port and Hambantota port in Sri Lanka play a key role in transiting and supporting the shipping trade of “the 21st-Century Maritime Silk Road”. In recent years, Chinese enterprises have made huge investments in the infrastructure construction of Colombo port and Hambantota port. The construction progress and development trend of Colombo port and Hambantota port have been attracting the attention of Chinese investment enterprises and the society. In this paper, multi-temporal high spatial resolution remote sensing images are used to monitor the infrastructure construction condition of Colombo port and Hambantota port from 2010 to 2017. According to the interpreted infrastructure information of the two ports, the international container terminal of Colombo and Hambantota port have completed their constructions. By the end of 2017, the international container terminal of Colombo built the container yards with 28.8 ha and roads with 32.6 ha. At the south of the international container terminal of Colombo, the 62.2 ha of reclamation area were built for the planned port city. In Hambantota port, 77 ha of container yards, 48 ha of roads and 2.9 ha of oil storage areas were constructed during this period. Meanwhile, the analysis of potential storage capacity of Colombo port and Hambantota port shows that the throughput of Colombo port may increase by 3 million tons per year while the throughput of Hambantota port will be over its designed 2.5 million tons per year. These analysis results are able to provide a useful reference for Chinese investment enterprises and the related research of “the Belt and Road”.  相似文献   

THRUST PACKAGES OF 1.68 Ga INDIAN SUPRA-CRUSTAL ROCKS IN THE MIOCENE SIWALIK BELT,CENTRAL NEPAL HIMALAYAS     

Harutaka Sakai    Yutaka Takigami    B.N.Upreti    D.P.Adhikary  WT  ”BX 《地学前缘》2000,(Z1)

THRUST PACKAGES OF 1.68 Ga INDIAN SUPRA-CRUSTAL ROCKS IN THE MIOCENE SIWALIK BELT,CENTRAL NEPAL HIMALAYAS  相似文献   

Shuffled-cards structure and different P/T conditions in the Sanbagawa metamorphic belt, Sakuma-Tenryu area, central Japan     

Michio Tagiri  Yoshiaki Yago and  Atsushi Tanaka 《Island Arc》2000,9(2):188-203

The Sanbagawa metamorphic terrain of the study area is divided into two units, the Shirakura and Sejiri units. The metamorphic thermal structure is interpreted on the basis of the degree of graphitization (GD) of carbonaceous material in pelitic schists. The areal variations of the metamorphic grade are presented by the distribution of GD calculated using the Lc and d₀₀₂ of carbonaceous material. As a result, the two units are classified into four metamorphic zones, respectively: A₁, A₂, B₁ and B₂ for the Shirakura Unit; and I₁, I₂, II₁ and II₂ for the Sejiri Unit. The metamorphic grades of A₁, A₂, I₁ and I₂ are included in the chlorite zone, and that of B₁, B₂, II₁ and II₂ in the garnet zone of the Sanbagawa metamorphism. The degree of graphitization at the boundary between A₂ and B₁ zones is the same as that between I₂ and II₁ zones. Detailed study on the variation of GD suggests that the present‐day structure of the study area is best interpreted as a model of shuffled‐cards structure. An estimated minimum thickness of a stack of continuous cards is about 25 m. The compositions of garnet in pelitic schists and of amphibole in basic schists are different from those in the identical metamorphic range of the Shirakura and Sejiri units. It is suggested that rocks of the Shirakura Unit were metamorphosed under higher P/T conditions than those of the Sejiri Unit.  相似文献   

Sr–Nd isotopic systematics and geochemistry of intermediate plutonic rocks from Ikoma Mountains, Southwest Japan: evidence for a sequence of Mesozoic magmatic activity in the Ryoke Belt     

Hiroaki Fujii  Yoshiaki Tainosho  Hiroo Kagami and  Takashi Kakiuchi 《Island Arc》2000,9(1):37-45

Abstract The Ryoke Belt in the Ikoma Mountains, Nara Prefecture, Japan, is composed mainly of various granitic, intermediate and gabbroic rocks. Igneous activity in this area is divided into two periods, early–middle Jurassic and late Cretaceous, based on isotopic dating. The intermediate plutonic rocks in the Fukihata area are composed of two rock types: Kyuanji quartz diorite and Fukihata tonalite. Rb–Sr whole-rock isochron ages have been determined for both plutonic rocks. Their ages and initial ⁸⁷Sr/⁸⁶Sr ratios are as follows: the Kyuanji quartz diorite has an age of 161.0 ± 17.9 Ma with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70727 ± 0.00007, while the Fukihata tonalite has an age of 121.4 ± 24.6 Ma with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70753 ± 0.00020. Our chronological results indicate that the Kyuanji quartz diorite belongs to the Jurassic mafic rocks, such as the Ikoma gabbroic mass, while the Fukihata tonalite belongs to the early Cretaceous granitic rocks. Both these intermediate plutonic rocks have different chemical characteristics and were derived from different magmas.  相似文献   

欧亚大陆山地垂直带数字集成系统的设计与应用   总被引：1，自引：0，他引：1  

赵芳  张百平  谭靖  韩芳  庞宇  姚永慧 《地球信息科学学报》2011,13(3):346-353

在欧亚大陆山地垂直带880个带谱点数据采集的基础上,设计和开发了山地垂直带数字集成系统。其功能：(1)垂直带谱可视化显示功能：实时生成垂直带地理分布图、垂直带堆积柱状图、上下限高度随经纬度变化曲线;(2)垂直带上下限提取和绝对高度和相对高度转化功能：提取山地垂直自然带分布上限和下限高度,进行垂直带的宽度和垂直带上限海拔...  相似文献   

中亚造山带南缘北山东段中生代以来阶段隆升：磷灰石裂变径迹年龄的制约     

唐卫东  魏立勇  何佳乐  刘天航  于锴  袁凯龙 《地质论评》2024,70(S1):17-18

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中亚造山带北山南部柳园洋晚古生代两阶段古地理演化     

牛亚卓  张东东  杨博  张宇轩  史冀忠  周俊林 《地质学报》2024,98(6):1683-1700

甘蒙北山地区位于中亚造山带中段,其间的柳园洋是古亚洲洋的重要分支之一,关于该洋盆的演化过程存在两阶段裂谷盆地和单阶段长期俯冲两种认识。柳园洋位于北山南部石板山地块和双鹰山地块之间,石板山地块的晚古生代沉积序列和物源变化完整记录了洋盆的古地理演化过程,对于重建区域构造演化有重要意义。此次研究聚焦石板山地块独山地区的上古生界火山- 沉积序列,通过砂岩碎屑颗粒组分和碎屑锆石U- Pb- Hf同位素分析,提供柳园洋古地理演化的约束证据。本文数据表明：独山地区下—中泥盆统碎屑锆石年龄为早古生代单峰式分布（~415 Ma）,来自于柳园洋向南俯冲在石板山地块边缘而形成的岩浆弧;上石炭统—下二叠统样品中出现了明显的中元古代碎屑锆石年龄（~1426 Ma）,来自于北侧的双鹰山地块和中天山地块,指示洋盆闭合事件;下二叠统碎屑锆石年龄主要为晚石炭世—早二叠世单峰式分布（301~290 Ma）,来自于裂谷火山活动。此外,本次研究通过对北山南部已发表物源学数据的统计计算,进一步证明并完善了古生代柳园洋两阶段演化模型：中奥陶世—中泥盆世,柳园洋双向俯冲至敦煌- 石板山地块和双鹰山地块之下;晚泥盆世,柳园洋闭合,直至石炭纪晚期,敦煌- 石板山- 双鹰山地块形成了统一的陆缘环境;早—中二叠世,柳园裂谷盆地逐步发育至原洋盆地。  相似文献   

内蒙古土牧尔台地区黑云母二长花岗岩及其暗色包体的成因及构造意义     

王挽琼  郗爱华  葛玉辉  白新会  王虎 《岩石学报》2021,37(4):1082-1098

内蒙古中部土牧尔台地区位于华北克拉通北缘,区内广泛发育黑云母二长花岗岩及暗色闪长岩包体,绝大多数包体与寄主岩石呈渐变过渡的接触关系.锆石LA-ICP-MS U-Pb定年结果显示,寄主岩石年龄为273 ～ 271Ma,包体年龄为268±2Ma,两者均形成于早-中二叠世.其中,寄主岩石具有高钾钙碱性、弱过铝质、高分异Ⅰ型花...  相似文献   

The geological evolution of the Gangpur Schist Belt,eastern India: Constraints on the formation of the Greater Indian Landmass in the Proterozoic     

Tuhin Chakraborty  Dewashish Upadhyay  Sameer Ranjan  Kamal L. Pruseth  Jayanta K. Nanda 《Journal of Metamorphic Geology》2019,37(1):113-151

The Central Indian Tectonic Zone (CITZ) is a Proterozoic suture along which the Northern and Southern Indian Blocks are inferred to have amalgamated forming the Greater Indian Landmass. In this study, we use the metamorphic and geochronological evolution of the Gangpur Schist Belt (GSB) and neighbouring crustal units to constrain crustal accretion processes associated with the amalgamation of the Northern and Southern Indian Blocks. The GSB sandwiched between the Bonai Granite pluton of the Singhbhum craton and granite gneisses of the Chhotanagpur Gneiss Complex (CGC) links the CITZ and the North Singhbhum Mobile Belt. New zircon age data constrain the emplacement of the Bonai Granite at 3,370 ± 10 Ma, while the magmatic protoliths of the Chhotanagpur gneisses were emplaced at c. 1.65 Ga. The sediments in the southern part of the Gangpur basin were derived from the Singhbhum craton, whereas those in the northern part were derived dominantly from the CGC. Sedimentation is estimated to have taken place between c. 1.65 and c. 1.45 Ga. The Upper Bonai/Darjing Group rocks of the basin underwent major metamorphic episodes at c. 1.56 and c. 1.45 Ga, while the Gangpur Group of rocks were metamorphosed at c. 1.45 and c. 0.97 Ga. Based on thermobarometric studies and zircon–monazite geochronology, we infer that the geological history of the GSB is similar to that of the North Singhbhum Mobile Belt with the Upper Bonai/Darjing and the Gangpur Groups being the westward extensions of the southern and northern domains of the North Singhbhum Mobile Belt respectively. We propose a three‐stage model of crustal accretion across the Singhbhum craton—GSB/North Singhbhum Mobile Belt—CGC contact. The magmatic protoliths of the Chhotanagpur Gneisses were emplaced at c. 1.65 Ga in an arc setting. The earliest accretion event at c. 1.56 Ga involved northward subduction and amalgamation of the Upper Bonai Group with the Singhbhum craton followed by accretion of the Gangpur Group with the Singhbhum craton–Upper Bonai Group composite at c. 1.45 Ga. Finally, continent–continent collision at c. 0.96 Ga led to the accretion of the CGC with the Singhbhum craton–Upper Bonai Group–Gangpur Group crustal units, synchronous with emplacement of pegmatitic granites. The geological events recorded in the GSB and other units of the CITZ only partially overlap with those in the Trans North China Orogen and the Capricorn Orogen of Western Australia, indicating that these suture zones are not correlatable.  相似文献