Surging of the southwestern part of the Laurentide Ice Sheet   总被引：1，自引：0，他引：1  

LEE CLAYTON  JAMES T. TELLER  JOHN W. ATTIG 《Boreas: An International Journal of Quaternary Research》1985,14(3):235-241

The southwestern part of the Laurentidc Ice Sheet, in central North America, repeatedly surged during the last part of the Wisconsin Glaciation. Evidence includes the extreme lobation of the ice margin, the gentle slopes of lateral moraines and other marginal features, a radiocarbon chronology indicating extremely rapid marginal advance and retreat, and the abundance of supraglacial flow till. Rapid ice movement was caused by subglacial water and was probably limited to areas of slowly permeable substrate, which slowed the escape of the water.  相似文献   

南海东北部海陆联测与海底地震仪探测   总被引：36，自引：0，他引：36  

丘学林  赵明辉  叶春明  王天楷  王平  张毅祥  夏戡原  李昭兴 《大地构造与成矿学》2003,27(4):295-300

利用三分量海底地震仪、陆上便携式地震仪和海上气枪震源在南海东北部首次进行了海陆联合的深地震探测,测线呈北北西-南南东方向,垂直于区域构造走向,总长达500km,所获得的数据质量好,深部信息丰富,可分辨出Pg、Pn、PmP等地震相,为南海东北部深部地壳结构及油气盆地形成演化的研究提供了重要的基础数据。  相似文献   

Metamorphic and Tectonic Evolution of the Hwacheon Granulite Complex, Central Korea: Composite P-T Path Resulting from Two Distinct Crustal-Thickening Events   总被引：1，自引：0，他引：1  

LEE  SEUNG RYEOL; CHO  MOONSUP 《Journal of Petrology》2003,44(2):197-226

The Hwacheon granulite complex (HGC), occupying the northeasternmargin of the Gyeonggi massif, consists mainly of garnetiferousleucocratic gneiss and leucogranite together with minor kyanite–garnetgneiss, aluminous gneiss, mafic granulite and garnet amphibolite.Mineral assemblages and reaction textures in various rock typesof the HGC document five distinct metamorphic stages: pre- (M₁)and peak (M₂) granulite-facies metamorphism; lower temperature,high (M₃) and low (M₄) pressure upper amphibolite-facies metamorphism;and local retrogression (M₅) producing andalusite-bearing assemblages.Each metamorphic stage can be integrated to give a compositeP–T path consisting of two distinct trajectories, characterizedby clockwise P–T loops at relatively high and low temperatures,respectively. The first P–T trajectory (M₁–M₃) correspondsto a Palaeoproterozoic tectonometamorphic event responsiblefor the formation of the granulite complex at  相似文献   

Testing the case for a Middle Pleistocene Scandinavian glaciation in Eastern England: evidence for a Scottish ice source for tills within the Corton Formation of East Anglia, UK   总被引：1，自引：0，他引：1  

JONATHAN R. LEE  JAMES ROSE  JAMES B. RIDING  BRIAN S. P. MOORLOCK  RICHARD J. O. HAMBLIN 《Boreas: An International Journal of Quaternary Research》2002,31(4):345-355

The provenance of the Happisburgh Till and Corton Till of the Corton Formation is investigated using erratic clast lithologies and allochthonous palynomorphs to test whether the long held assumption that they were deposited by ice that originated in Scandinavia is valid. The results show a wide range of lithologies including Carboniferous Limestone and Coal Measures, and Permian Magnesian Limestone that are not found in Scandinavia, and an absence of distinctive Scandinavian material such as rhomb porphyry and larvikite. Lithologies found indicate deposition by an ice sheet which flowed southwards into north-east East Anglia from central and southern Scotland eroding and transporting materials derived from outcrops in these areas and from eastern England and the western margins of the southern North Sea Basin. It is concluded that the long held assumption that the Happisburgh Till and Corton Till of the Corton Formation were deposited by a Scandinavian ice sheet is erroneous and that they were instead deposited by Scottish ice.  相似文献   

Conodonts from the Upper Cambrian Sesong and Hwajeol Formations in the Sabuk Area, South Korea     

LEE Byung-SuDepartment of Earth Science Education  Chonbuk National University  Jeonju  -  Korea Zhu Xiling 《《地质学报》英文版》2002,76(2):155-165

This paper presents a conodont biostratigraphic study on the Upper Cambrian Sesong and Hwajeol Formations in the Sabuk area, Korea. Two samples near the base of the Sesong Slate at the Pukil section contain lower Upper Cambrian conodonts, comprising Furnishina furnishi, F. kranzae, F. pernical, F. triangulate, Hertzina elongata, Laiwugnathus doidyxus?, Phakelodus elongatus, Muellerodus? obliquus, Westergaardodina matsushitai and W. moessebergensis. This is the first conodont record of the Upper Cambrian formations recovered yet in the northern limb of the Paekunsan syncline. The faunal assemblage is correctable with the lower Upper Cambrian W. matsushitai Zone of North China. Four local biozones are recognized in the Hwajeol Formation, i.e. the Proconodontus, Eoconodontus notchpeakensis, Cambrooistodus minutus and Cordylodus proavus Zones in ascending order. This zonal scheme is essentially equivalent to that of the southern limb of the Paekunsan syncline and they are correlatable with zones in other pa  相似文献   

澳大利亚南极科学数据管理综述   总被引：4，自引：0，他引：4  

凌晓良  LEE Belbin  张洁  朱建钢  张侠  汪大立 《地球科学进展》2007,22(5):532-539

系统概述了澳大利亚国家南极数据政策、组织机构、管理模式、实施策略与未来发展所面临的问题。在此基础上分析澳大利亚南极数据工作的发展与实效，并回顾了中国的极地数据管理工作，初步表明建立一个有效的组织框架是顺利开展数据管理与共享工作的基础，完全基于Web的数据管理与服务对科学项目的管理与研究成果的产出具有较大的促进作用。同时可以看出，国家层面的数据管理工作首先必须有明确的国家数据政策作引导；需要建立各种相应的数据标准与规范以及基于Web的数据管理、共享与服务平台；当然更离不开一支进行数据管理、服务与技术支持的专业队伍，并通过工作绩效评价系统对各个环节进行评价和考核。其中，为数据（集）编写完整、准确的元数据始终是数据管理中最重要的基础工作。  相似文献   

Examination of model-estimated ecosystem respiration using flux measurements from a cool-temperate deciduous broad-leaved forest in central Japan   总被引：1，自引：0，他引：1  

AKIHIKO ITO  MOTOKO INATOMI  WENHON MO  MISUN LEE  HIROSHI KOIZUMI  NOBUKO SAIGUSA  SHOHEI MURAYAMA  SUSUMU YAMAMOTO 《Tellus. Series B, Chemical and physical meteorology》2007,59(3):616-624

  相似文献   

Dependence of trajectory accuracy on the spatial and temporal densities of wind data     

TAE-YOUNG LEE  SANG-WOOK PARK  SEUNG-BUM KIM 《Tellus. Series B, Chemical and physical meteorology》1997,49(2):199-215

  相似文献   

Preliminary Examinations of the Ore-forming Process by Fluid Mixing – a Test of MIX99     

Kenichi HOSHINO  Yuki YAMAMOTO  Xiangping GU  Su Young LEE  Makoto WATANABE 《Resource Geology》2000,50(3):185-190

Abstract: Possible ore deposition by fluid mixing was preliminarily examined using MIX 99, a FORTRAN program developed for simulating water-rock interactions. We consider mixing of two fluids, the low f_O2 and high temperature source fluid and the high f_O2 and low temperature seawater. Oxygen fugacity of a mixed fluid formed by titration of seawater into the source fluid gradually decreases with decreasing temperature (model A). Sequential precipitation of ore-forming minerals was examined in this model. On the other hand, simultaneous precipitation of the minerals could be followed by simulation of instantaneous overall mixing of the two fluids (model B). Results of simulation of the both models revealed that a temporal sequence of mineralization observed in the Karuizawa mine, NE Japan, can be formed by model A, while model B is suitable for the mineralization of an active chimney found in the Rainbow hydrothermal area of the Mid-Atlantic Ridge.  相似文献   

大气折射率起伏对雷达波的散射     

李其琛  吕达仁 《气象学报》1963,33(1):115-125

研究大气折射率起伏对雷达波的散射时,得到的主要結果有以下两点: 1.在适当的大气条件下,折射率起伏构成的后向散射波能够超出一般雷达的灵敏度之上,它的量級正好和雷达观測到的气象“仙波”相同.根据这一結果和其他事实,作者认为起伏的后向散射可能是形成气象“仙波”的重要机制。 2.推导了表示雷达波在折射率有起伏的介貭中传播时,强度随距离变化的方程式,結果发現:一般情况下,散射效应不致引起波的强度的显著变化.但是,当大气折射率起伏的尺度长較小、輻度較大、并且雷达波瓣較窄时,散射效应会引起波瓣的加寬。  相似文献