晚新生代青藏高原岩溶地貌及其演化   总被引：3，自引：0，他引：3       下载免费PDF全文

高全洲  崔之久  刘耕年  伍永秋  张叶春 《古地理学报》2001,3(1):85-90

本文在野外考察的基础上并参照洞穴次生方解石的年代资料和有关文献,指出青藏高原目前所见到的岩溶地貌主要是第三纪古岩溶地下部分经后期剥蚀形成的。更新世间冰期至少在高原南部,湿热型岩溶地貌过程得以延续;更新世冰期在灰岩山地冰川槽谷的边缘,冰川融水作用亦可发育小型洞穴。现代灰岩表面一些深度在十数cm以下的平行溶沟则形成于全新世。晚新生代以来青藏高原岩溶地貌经历了一个从低海拔到高海拔、从较低纬度到较高纬度的三维演化过程。  相似文献   

地理信息系统在洛阳城市规划与建设中的应用   总被引：2，自引：0，他引：2  

张开广 《测绘学院学报》2002,19(3):232-234

主要讨论洛阳市九都路和定鼎路立交桥建设中所使用的地理信息系统技术，土石方计算方法以及拆迁量计算方法等。  相似文献   

论中国地貌图的研制原则,内容与方法—以1：4000000全国地貌图为例   总被引：7，自引：2，他引：7  

陈志明 《地理学报》1993,48(2):105-113

该图以多层次表示法和表列式分解型图例,着重表现构造地貌为基础的内外力地貌成因、形态及其发展过程的基本规律。在内力方面,采用板块构造理论为指导,表现了构造地貌;外力方面,除表现传统的堆积成因形态类型外,辅以气候地貌的地带分异;而形态分类则利用DTM,对国土地形进行了基本形态要素的机助分析与制图,并引进地形起伏度概念,调整了传统的形态分类方案。通过项目研制,作者力求探讨一种符合现代地貌学理论,服务于科研、教学和国土整治的新型国家地貌图。  相似文献   

太白山第四纪冰碛物特征与冰期   总被引：3，自引：0，他引：3  

马秋华  何元庆 《冰川冻土》1988,(1)

在晚更新世早期(Q_3~1)和晚期(Q_8~3),太白山主峰八仙台先后发生过两次冰川作用,即三爷海冰期和太白冰期。其中太白冰期又可划分为早太白和晚太白两个副冰期。经人工剖面证实的三道不同时期的侧碛垄分别与上述冰期相对应。各种冰蚀地貌都受到该区构造的控制和影响。  相似文献   

The pre-glacial evolution of Wales     

Yvonne Battiau-Queney 《地球表面变化过程与地形》1984,9(3):229-252

The classical explanation of the development of the Welsh landscape by the effects of a pulsed ‘eustatic’ uplift during the Cenozoic times is challenged by new data on the geology and geomorphology of Wales and the adjacent regions. The post-Caledonian surface developed over most of Wales in the upper Westphalian plays a major role in landform development. Since its emergence before mid-Cretaceous times, the Welsh Massif has suffered a long subaerial evolution which favoured a powerful chemical weathering. In Anglesey and St. David's Land, residual hills were formed by a process of differential weathering, and downwearing in saprolites. The Millstone Grit quartzites have been deeply weathered and dolines or flat-bottomed basins have been developed. From Cretaceous to Miocene times, a morphotectonic equilibrium has existed between uplift and denudation, so that, in the major part of Wales, the original planation surface was constantly maintained by lowering on itself and in some places it is possible to prove that no more than a few dozen metres of rock thickness disappeared during that period. Several main escarpments were produced by the warping of the planation surface along sharp flexures, during Neogene times. The Cenozoic vertical movements were controlled by the Caledonian or pre-Caledonian tectonic pattern which has divided the continental crust into major structural units. Welsh tectonic development is related to the opening of the North Atlantic, associated stresses reactivating ancient lines of weakness in the heterogeneous lower crust or upper mantle.  相似文献   

Holocene alluvial fan and terrace formation in the Bowland Fells,Northwest England     

A. M. Harvey  W. H. Renwick 《地球表面变化过程与地形》1987,12(3):249-257

In the Bowland Fells, Lancashire, northwest England, in the headwater valleys of the Hodder river system, is a suite of Holocene fluvial landforms. Debris cones and alluvial fans at tributary junctions, and river terraces along the main valleys post-date late Pleistocene forms and pre-date the modern valley floor alluvial forms. Eight ¹⁴C dates from wood samples incorporated within the terrace and fan deposits have allowed two main phases of Holocene erosion to be identified with debris cone/fan deposition taking place after c. 5400 BP but before c. 1900 BP and again at c. 900 BP. Some of the fans and cones are complex with deposits attributable to both phases; others are simple and attributable only to the later phase. In the headwaters an upper terrace at c. 5400 BP pre-dates the cones and a lower terrace is contemporaneous with the first debris cone phase. Lower downvalley the youngest of three terraces date from c. 5000 BP or earlier indicating that the sequence is less complex downstream.  相似文献   

Effects of glaciations and permafrost upon the development of karst in Canada     

Derek Ford 《地球表面变化过程与地形》1987,12(5):507-521

Canadian examples suggest that karst landforms may be divided into eight types in terms of their temporal relationships to the record of repeated Quaternary glaciations. Two types are postglacial, two are subglacial, one type occurs where glacial features are adapted to karstic drainage, and three types display sequences of karstic and glacial action. Glacier effects upon karst landforms and their underlying aquifers display the gamut of possibilities. They may destroy, inhibit, preserve, or stimulate karst development. Where continuous permafrost is maintained when covered by glacier ice, postglacial karst is limited to the active layer epikarst. Where permafrost is thawed beneath ice or during deglaciation there are a variety of postglacial karst developments, depending in part upon climate and in part upon local lithologic and relief conditions.  相似文献   

Limited modification of mid-latitude landscapes by ice sheets: The case of northeast Scotland   总被引：1，自引：0，他引：1  

Adrian M. Hall  David E. Sugden 《地球表面变化过程与地形》1987,12(5):531-542

The paper uses a case study in Scotland to examine the amount and processes of landscape modification by Quaternary ice sheets. There is an inverse correlation between the distribution of landforms of glacial erosion and pre-glacial landscape remnants in northeast Scotland. The implication is that in places ice sheets can preserve a pre-glacial landscape unscathed, while elsewhere they remove the pre-glacial weathered rock. The location of glacial protection or erosion is strongly influenced by the topography and its influence on former ice sheet flow and basal thermal regime. The classic glacially eroded landscape of areal scouring can be produced by the removal of only 10–50 m of weathered rock. Furthermore rock basins, often regarded as the hallmark of glacial erosion, may be directly inherited from the pre-glacial pattern of deep weathering.  相似文献   

A study of dells in the new forest,Hampshire, England     

Cyril G. Tuckfield 《地球表面变化过程与地形》1986,11(1):23-40

Dells in the New Forest are described as amphitheatre-shaped hollows, perched on valley sides, sometimes singly, in other places in groups tributary to small dry valleys. They have steep rear walls and sides, flatfish floors, and convex lips, usually without any water-worn channels. The slopes on which they occur, cut in Eocene sands and clays, have been subjected to solifluction, and this has produced wide gently sloping terraces at the foot of the hillside. Superficial deposits within the New Forest dells are divided into two groups by process: a lower head of fragmented flints in a sandy or clayey matrix, assigned to Zone III; overlying colluvial deposits including slumped material and slope wash, dated by reference to a buried soil to Zone VIIa. Although scoured by solifluction, other processes probably account for the initial formation of the hollows, and nivation is suggested. The dells are compared with the chalk coombes of southern England and the dellen of European and other writers. A possible chronology is suggested for the New Forest dells.  相似文献   

可可西里东部地区的夷平面与火山年代   总被引：18，自引：1，他引：18       下载免费PDF全文

李炳元  潘保田  高红山 《第四纪研究》2002,22(5):397-405

青藏高原夷平面及其年代是高原隆升、时代和幅度研究中的一个关键问题。可可西里东部地区通过1∶100000航测地形图所示的山顶面形态特征分析表明,本区广泛分布的山顶平坦地形面为青藏高原主夷平面的一部分,其海拔高度大多在4900～5200m。本区平坦顶面的熔岩方山常与夷平面交叉分布,也为高原主夷平面一部分,其同位素年代19.6～6.95MaB.P.之间的有39个(9.9～6.95MaB.P.有17个)。又据本区相邻的山间盆地内的火山地貌年龄推论,夷平面形成于9.9～6.95MaB.P.之后,3MaB.P.之前已形成  相似文献