Elemental and Sm-Nd isotopic geochemistry on detrital sedimentary rocks in the Ganzi-Songpan block and Longmen Mountains   总被引：1，自引：0，他引：1  

Chen Yuelong  Liu Fei  Zhang Hongfei  Nie Lanshi  Jiang Liting 《Frontiers of Earth Science》2007,1(1):60-68

Systematic results of major and trace element geochemistry and Sm-Nd isotopic geochemistry on detrital sedimentary rocks of Precambrian to Triassic in the Ganzi-Songpan block and Longmen Mountains are presented. The rocks are classified into greywackes or feldspar sandstones, grains of which are the mixtures of mafic rocks, felsic rocks, and quartz+calcite. Total rare earth elements (REE) contents of the rocks increase gradually and negative Eu anomalies become more obvious from Precambrian to Triassic, which may indicate intensifying crustal anatexis. Tectonic setting was stable during the Late Paleozoic, therefore there are obvious negative Ce anomalies. Nd model ages are between 1.6 Ga and 2.4 Ga, which are very similar to those of the Yangtze craton, South Qinling and North Qinling belts and quite different from those of the North China craton. Therefore, provenance of the sedimentary rocks in the Ganzi-Songpan block and Longmen Mountains was the Yangtze craton and/or the Qinling orogen, which evolved on the basis of the Yangtze craton. The correlation between provenances and tectonostratigraphic strata of the western Yangtze craton shows that the source materials should be primarily from Neoproterozoic. Secondary sources were Archean and Paleoproterozoic strata. Triassic clastic sedimentary rocks contain Late Paleozoic mantle-derived materials, represented by the Emeishan Permian flood basalts. Spatial distribution of initial Nd isotopic compositions indicates that denudating areas were in the east and the north and depositing areas of deep water were in the west and the south for the Ganzi-Songpan basin during Triassic. Translated from Geology in China, 2006, 33(1): 109–118 [译自: 中国地质]  相似文献   

青藏铁路沿线航磁特征及找矿远景预测     

乔春贵  王德发  刘伟  王乃东  张玄杰  宋正范 《物探与化探》2012,36(6):915-921

通过对青藏铁路沿线航磁反映的大地构造背景的综合分析,对青藏铁路沿线找矿远景进行了预测.依据不同的成矿地质背景和航磁反映的构造—岩浆—热液环境、局部异常特征,结合大地构造位置,将研究区划分为7个成矿带.圈定铁、铜、铅、锌、金、银、铬等多金属找矿远景区125个,其中一级找矿远景区49个,为该地区地质调查和矿产资源评价提供了重要信息.  相似文献   

论大地构造学的发展          下载免费PDF全文

万天丰 《地球科学》2019,44(5):1526-1536

大地构造学是研究地球物质在时间和空间演化的学问,是构造地质学的一门重要的分支学科,是一门涉及知识面很宽的学问.大地构造学需要朝定型、定向、定时、定位和定量的研究方向前进,需要通过"行万里路,读万卷书",经过长期的知识积淀才可能进行扎实的研究,以便逐渐接近科学的真理.槽台假说是一种过时的认识.板块构造学说起源于海洋地球物理调查,它是一个仍在继续发展中的大地构造学说,强调各个岩石圈板块是以水平运移为主的,但是其动力学机制则至今尚未完全解决,仍在探索之中.  相似文献   

大陆中洋壳俯冲增生杂岩带特征与识别的重大科学意义   总被引：3，自引：0，他引：3       下载免费PDF全文

潘桂棠  肖庆辉  张克信  尹福光  任飞  彭智敏  王嘉轩 《地球科学》2019,44(5):1544-1561

大洋或弧后洋盆俯冲增生是大陆地壳增长的主导地质作用.重建大陆中消亡的洋地层岩石组合序列是当代大陆动力学和地学研究的重大前沿.洋壳消减杂岩带的厘定是洋板块地质构造重建乃至全球大地构造研究之纲,是理解区域大地构造形成演化及动力学的核心.俯冲增生杂岩带的基本特征:(1)俯冲增生杂岩带物质组成的共性是:以强烈构造变形洋底沉积的硅质岩-硅泥质岩-粉砂岩、凝灰岩;弧-沟浊积岩等为基质;以洋岛-海山灰岩-玄武岩及塌积砾岩,洋内弧残留岩块,超镁铁质蛇绿岩、绿片岩、蓝片岩等为岩块.(2)变形样式:同斜倒转冲断叠瓦构造、增生柱前缘重力滑动构造以及泥质岩的底辟构造;增生楔前缘变形和增生形式受控于大洋或弧后洋盆的规模和洋壳的俯冲速度,也取决于陆缘碎屑供给量及洋底沉积厚度和岩性.(3)宽度和厚度:厚常达几千米,宽达几十公里至数百公里,延长上千公里,是洋壳俯冲消亡过程洋盆地层系统及陆缘沉积物加积的结果.(4)形成机制:是大陆碰撞前大洋(或弧后洋盆)岩石圈俯冲消减的产物.结合带中的早期俯冲增生杂岩带往往卷入晚期的构造混杂作用.  相似文献   

统一构造理论初探   总被引：4，自引：0，他引：4  

毕思文 《地学前缘》1998,(Z1)

以地球系统科学为指导思想,提出统一构造理论的新观点和理论基础,初步建立了理论体系框架。提出统一引力场表示理论,用Ｎｅｗｔｏｎ位算子将地球内、外扰动引力场统一。通过对地球不同圈层水平速度矢量场的对比分析,提出不同圈层的水平运动速度矢量场具有高度的相似性和统一性,且与地球自转密切相关的认识。根据观测数据,探讨板块的统一动力源。研究了幔柱构造特征,提出地幔热柱构造的动力学模型。利用积分关系法求出地表热流与岩石圈厚度的关系,提出大陆岩石圈的统一热模式和大陆地表热流经验关系式。  相似文献   

BOOK REVIEWS     

《The Professional geographer》1984,36(2):250-283

Book Reviewed in this article: Geography and the Third World. International Seminar, 14–18 May 1980, Kuala Lumpur, Malaysia . Ishmail Ahmad and Jamaluddin Md Jahi, eds. The Growth Dilemma: Residents' Views and Local Population Change in the United States . Mark Baldassare. Sport and Place: A Geography of Sport in England, Scotland & Wales . John Bale. The Deindustrialization of America: Plant Closings, Community Abandonment, and the Dismantling of Basic Industry . Barry Bluestone and Bennett Harrison. Selected Essays 1963–1975: Carl O. Sauer . Bob Callahen, ed. Housing and Planning in the Countryside . G. Clark. Conflict, Politics and the Urban Scene . Kevin R. Cox and R. J. Johnston, eds. Thematic Maps: Their Design and Production . David J. Cuff and Mark T. Mattson. Wine: A Geographic Appreciation . Harm Jan de Blij. USSR in Maps . J. C. Dewdney. Political Geography: A Contemporary Perspective . Ramesh D. Dikshit. Rethinking Human Adaptation . Rada Dyson-Hudson and Michael A. Little, eds. Sacred Sands: The Struggle for Community in the indiana Dunes . J. Ronald Engel. Geography of the Biosphere . A. Furley and Walter W. Newey. Disaster and Reconstruction . Robert Geipel. Glasgow: The Making of a City . Andrew Gibb. Design for Arid Regions . Giden S. Golany, ed. Urbanization and Cancer Mortality: The United States Experience, 1950–1975 . Michael R. Greenberg. Geology in the Nineteenth Century: Changing Views of a Changing World . Mott T. Greene. Colonización y Destrucción de Bosques en Panamá . Stanley Heckadon Moreno and Alberto McKay, eds. Urban Geography: A First Approach . David T. Herbert and Colin J. Thomas. The Visual and Spatial Structure of Landscapes . Tadahiko Higuchi. Climate from Tree Rings . M. K. Hughes, P. M. Kelly, J. R. Pilcher, and V. C. LaMarche, Jr., eds. The structure of Nineteenth Century Cities . James H. Johnson and Colin G. Pooley, eds. The American Planner: Biographies and Recollections . Donald A. Krueckeberg, ed. Urban Land Policy For the 1980s, the Message for State and Local Government . George Lefcoe, ed. Regional Planning: Evolution, Crisis and Prospects . Gill C. Lim, ed. Relevance and Ethics In Geography . Bruce Mitchell and Dianne Draper. China: The Geography of Development and Modernization . Clifton W. Pannell and Laurence J. C. MA. The Urban Retailing System . Robert B. Potter. Hants. Nonconventional Energy Resources . Philip R. Pryde. Caribbean Migrants: Environment and Human Survival on St. Kitts and Nevis . Bonham C. Richardson. Population and Resources . Harry Robinson. East Los Angeles: History of A Barrio . Ricardo Romo. Integrated Impact Assessment . Frederick A. Rossini and Alan L. Porter, eds. Environmental Aesthetics: Essays in Interpretation . Barry Sadler and Allen Carlson, eds. Earthwatch . Charles Sheffield. Field Techniques and Research Methods in Geography . Robert H. Stoddard. Haiti: Land of Poverty . Robert J. Tata. Weathering and Erosion: Sources and Methods in Geography . Stephen T. Trudgill. Once Beneath the Forest. Prehistoric Terracing in the Río Bec Region of the Maya Lowlands . B. L. Turner, II. The Historical Geography of Scotland since 1707 . David Turnock.  相似文献   

Granitic and monzonitic rocks dredged from the southeast Australian continental margin     

T. C. T. Hubble  G. H. Packham  D. A. F. Hendry  I. McDougall 《Australian Journal of Earth Sciences》2013,60(5):619-630

Four Middle Devonian (381 Ma) granodiorite samples have been recovered from two dredge sites approximately 65 km east of Green Cape, New South Wales. The granodiorite samples are similar in age and composition to members of the Moruya Suite and probably form an along‐strike extension of that suite. The location of granodiorite on the southeastern margin requires that a piece of continental lithosphere was located to the present east of the study area in the Devonian. This piece of lithosphere may now be located somewhere on the western Lord Howe Rise.

A sample of Early Cretaceous leuco‐quartz monzodiorite was also recovered from a dredge site approximately 45 km north‐northeast of Dalmeny, New South Wales. It represents a body that was intruded at essentially the same time as, and is inferred to be of similar origin to, the syenite rocks of the nearby Mt Dromedary and Montague Island complexes.  相似文献   

论中国东部中、新生代大地构造的基本特征   总被引：3，自引：3，他引：0  

林宗满 《地质力学学报》2010,16(3):246-259

把中国东部中、新生界划分为6个构造-沉积旋回, 相应地发育6期构造运动主幕, 侏罗纪末幕运动是一场变格运动。进一步将研究区构造形变史划分为两个形变阶段和一个过渡阶段。两个构造形变阶段发育两种类型的沉积盆地、两种型式的构造体系, 它们之间存在着广泛的构造不整合, 显示二元结构即为中国东部中、新生代大地构造的基本特征。   相似文献   

Parentage of low‐grade metasediments in the Sanbagawa belt,eastern Shikoku,Southwest Japan,and its geotectonic implications     

Kazuo Kiminami 《Island Arc》2010,19(3):530-545

This study examines the geology of low‐grade (chlorite zone) metamorphic rocks in the Sanbagawa belt and of a Jurassic accretionary complex in the Northern Chichibu belt, eastern Shikoku, Japan. The bulk chemistries of metasandstones and metapelites in the Sanbagawa belt of eastern Shikoku are examined in order to determine their parentage. The Sanbagawa belt can be divided into northern and southern parts based on lithology and geologic structure. Geochemical data indicate that metasediments in the northern and southern parts are the metamorphic equivalents of the KS‐II (Coniacian–Campanian) and KS‐I (late Albian–early Coniacian) units of the Shimanto belt, respectively. The depositional ages of the parent sediments of low‐grade metamorphic rocks found in the Sanbagawa belt and the Jurassic Northern Chichibu belt, indicate a north‐younging polarity. In contrast, sedimentological evidence indicates younging to the south. These observations suggest that a tectonic event has resulted in a change from a northerly to southerly dip direction for schistosity and bedding in the Sanbagawa and Northern Chichibu belts of eastern Shikoku. The younging polarity observed in the Sanbagawa and Northern Chichibu belts, together with previously reported data on vitrinite reflectance and geological structure, indicate that the Northern Chichibu belt was part of the overburden formerly lying on top of the Sanbagawa low‐grade metamorphic rocks.  相似文献   

新疆北部壳体大地构造演化与运动初步研究   总被引：9，自引：3，他引：6  

杨牧  彭省临  杨斌  刘亮明 《大地构造与成矿学》2005,29(1):113-121

位于亚洲大陆中腹的新疆北部地区,是由不同壳块组成的复合型大陆壳块区,经历了长期复杂的壳体运动-演化历程,造就了该区不同地段岩石圈结构和构造的差异。本文在前人研究的基础上,运用壳体大地构造学的研究思路和方法,通过对该区地质-地球物理特征和壳体结构的分析,将该区划分为 4个不同性质和地壳结构的壳块,其中天山地区又可进一步分为东、西两段。文章分析了区域壳体的运动 -演化特征,并初步认为东、西天山在深部地球物理特征、基底性质和前地台期的构造演化,可能分属不同的构造演化体制。中新生代全区先后经历了地台演化阶段之后,陆续发生活化作用,由于不同地段地壳和岩石圈结构的差异,形成浅部地壳不同的活化地质构造特征。  相似文献