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1.
崂山古冰川遗迹的地质证据   总被引:1,自引:0,他引:1  
崂山是中国海岸线上的最高峰。研究发现,崂山发育有典型的古冰川侵蚀和堆积地貌,拥有我国东部罕见的冰碛海岸和冰碛扇等地貌类型。更新世期间,崂山至少发育过4次古冰川作用。更新世早期,崂山东部的雪线为60-90m(现代海拔),崂山及其周围共发育60余条古冰舌,东部的冰舌一直伸入黄海之中。孢粉组合特征说明,崂山在冰期具备形成冰川的气候条件;堆积物粒度曲线显示为冰川成因的沉积特征。研究还发现,中国东部的古冰川遗迹可能大部分被埋藏起来;区域地形特征和当地气候条件是决定雪线高度的关键因素。  相似文献   

2.
更新世中国东部盛行季风,长江谷地产生冰川,庐山冰川发育、更新世亚洲东部雪线降低,鄱阳湖畔有发育完美的羊背石及冰溜面,终碛及冰水沉积物。有3次冰川期:庐山鄱阳冰川期、大姑冰川期、庐山冰川期  相似文献   

3.
神农架大九湖地区更新世冰川遗迹的初步研究   总被引:3,自引:0,他引:3  
作者通过两次实地调查,发现神农架大九湖地区更新世冰川遗迹有冰斗、槽谷、基岩鼓丘和侧碛等。冰碛砾石砾向组构分析表明砾石a轴走向大多与所在谷地走向平行,倾角18~23°;砾石ab面倾向离散,倾角15—20°。冰碛细粒部分79.1—84.5%由粉砂和砂组成,粒度频率曲线呈双峰态。冰碛石英砂表面电镜扫描成象表明砂粒表面具有典型冰川砂的特征.根据冰川地貌特征和室内分析结果,本文把该地区晚更新世气候期划分为两次冰期和一次冰缘期。  相似文献   

4.
北门江流域更新世沉积广布、厚度巨大.在对区内的建筑砂矿进行成矿背景条件研究时利用了陆地卫星TM图像与区内的地质地球物理资料进行综合解译,发现了区内的冰蚀台面、冰洼、冰斗、冰川槽谷和冰碛堤、冰碛裙、冰水扇等冰川作用遗迹.通过对冰蚀、冰碛地貌的研究,发现它们之间是一系列有规律的组合,有其密切的成生联系,是更新世多次冰川作用的结果.  相似文献   

5.
本文运用古地理和地貌学分析方法探讨新疆博格多峰西北三工河谷地古冰川地貌和冰期问题。提供了新观察到的一些古冰川地貌遗迹资料,尝试分出五次冰期。简述了更新世以来的地貌发育过程。对天池湖前大坝上部堆积物成因提出了新看法,并讨论了本区第四纪古冰川发育模式。  相似文献   

6.
王志麟  李博 《科技信息》2011,(1):118-118,110
根据冰川地貌和地形特征,岩性和冰川沉积物的风化程度,认为贺兰山地区发育冰川作用,既末次冰盛期(LGM)。根据平衡线(ELA)处6-8月多年平均气温T)和年降水量(P)的关系,计算贺兰山理论雪线高度为4724±100m。本文分别采用冰斗底部高程法(简称CF)、冰川末端到山顶高度法(简称TSAM)、冰川末端至分水岭的平均高度法(,称Hofer)及积累面积比率法(简称AAR)来计算贺兰山古雪线的高度为3035-3178m,平均值3101m,考虑到末次冰盛期后地壳上升67m,当时实际雪线高度为3034m.冰盛期的雪线降低值为1623±100m。  相似文献   

7.
对长江中下游第四纪冰川发育的新认识   总被引:6,自引:0,他引:6  
早在20世纪30~40年代,李四光就已开始对我国长江中下游第四纪冰川发育问题进行研究。本文通过对长江中下游在冰期时的古气候、山体高度及雪线高度的研究,认为气候变冷和高山存在是长江中下游第四纪冰川发育最关键的条件。尤其是后者对发育冰川起着积极和直接的作用。  相似文献   

8.
本文从太白山丰富多样的冰川、冰缘地貌中,获得了两次雪线和两次石海线的信息。经过对比分析,拟出了太白山地区晚更新世以来的环境变化模式。  相似文献   

9.
通过对北京市东北部平谷新生代盆地地层岩性、水文条件、深部构造、微小地震和盆地形态特征综合分析,提出平谷盆地并非第四纪断陷盆地,而是岩溶塌陷盆地的新认识。综合研究认为平谷盆地内基岩断裂可能大量发育;但新生代夏垫-马坊断裂带并没有在平谷盆地内发育;造成平谷盆地新生代断裂密布假象的原因是基岩埋藏古地貌;平谷盆地古溶洞形成时代可能为上新世-早更新世,盆地可能在早更新世发生塌陷,形成最初的盆地雏形。  相似文献   

10.
利用《中国第二次冰川编目》的数据和卫星图, 结合野外地貌观测, 探讨喜马拉雅山亚东?康马段的冰川平衡线高度(ELA)、分布特征及影响因素。结果表明, 研究区现代冰川平均ELA 为5717 m, 库拉岗日地区稍高, 为5840~5957 m, 白马林岗日地区较低, 为5333~5373 m, 反映气候与地形大势对冰川ELA的控制。此外, 山脉的走向、坡向、冰川地形坡度以及冰川表面冰碛覆盖、雪崩等对冰川ELA有不同程度的影响。  相似文献   

11.
Isolated NE-SW stretching the Helan Mountain massif, separating the temperate grassland of the Ordos plateau from the Tenggeli Desert, is a key position of studying the glacier development in west China as well as the coupling conditions of climate change with tectonic uplift. The glacial landforms and deposits including cirques, peaks, knife-edge ridges, lateral moraines, and terminal moraines distribute above 2800 m a.s.l. in the middle part of the Helan Mountain. This distribution indicates that here was once glaciated during the late Quaternary. Morphology features show a clear sequence of landscape forming events took place throughout the Helan Mountain. Laboratory optically stimulated luminescence (OSL) and accelerator mass spectrometry radio-carbon dating (AMS 14 C) results indicate a late history of glacial advance. Late Pleistocene glaciers in the middle part of the Helan Mountain advanced to near their positions at least four times, and the glacial sequences can be assigned as the middle stage of last glacial cycle (MIS3b, 43.2±4.0 ka), last glacial maximum (LGM, ~18 ka), late glacial (12.0±1.1 ka) and neo-glacial (3.4± 0.3 ka) respectively. Adopting equilibrium line altitude ~2980 m of last glacial maximum and the modern theoretical snowline altitude ~4724 m as the maximum amplitudes, and the standard marine isotope curve (MIS) as the glacial equilibrium line change since the Gonghe Movement (150 ka), the relationship between the mountain altitude and glacier development is discussed herein. Compared with other environmental indexes such as the loesspaleosol and ice core, conclusions are made that glacier advances in the Helan Mountain during the late Quaternary obviously depended on the coupled control of tectonic uplift of mountain with the climate condition. It is at last glaciation that the mountain reached the altitude above snowline and coupled with the glacial climate. The glacial advances occurred in the early and middle stages of last glacial cycle after the Gonghe Movement.  相似文献   

12.
Geologic and geomorphologic evidence from the Shaluli Mountain indicates that the planation surface that formed in the Late Tertiary disintegrated during the Late PUocene-Early Quaternary. At the same time, rift basins appeared on some parts of the planation surface, and began to accumulate fluvial-lacustrine sediment. These are interpreted as being the response of this region to Phase-A of the Qingzang Teetnnic Movement. After this, the Shaluli Mountain eontinued to rise in several pulses. Faulting and incision by some large tributaries of the Jinsha and Yalong Rivers resulted in several rift river valleys and the earliest terraces. Generally. the planation surface in this region had been uplifted to ahout 3500--3700 m a.s.I, no later than 550-600 ka BP. after the Kunlun-Huanghe Tectonic Movement, and coupled with global glacial climate, and resulted in the earliest glaciation recognized so far in the Hengduan Mountains. At the same time, Ioess was deposited in the Ganzi area of the northern Shaluli Mountain. During the last glacial period, the Shaluii Mountain approached its present altitude and developed several large ice caps, such as the Daocheng Ice Cap and Xinlong Ice Cap, as well as several huge valley glaciers. These paleoglaciers produced some of the most Spectacnlar glacial topography on the Tibetan Plateau.  相似文献   

13.
Late Pleistocene glaciation of the Changbai Mountains in northeastern China   总被引:6,自引:0,他引:6  
Zhang  Wei  Niu  Yunbo  Yan  Ling  Cui  Zhijiu  Li  ChuanChuan  Mu  Kehua 《科学通报(英文版)》2008,53(17):2672-2684
The Changbai Mountains (2749 m a.s.l.) in northeastern China are one of the typical mountain regions with glaciation since late Pleistocene as evidenced by well-preserved erosive and accumulative landforms at elevations above 2000 m a.s.l, formed by glaciers around the crater lake, Tianchi Lake. Cirque glaciers developed on both the inner and outer sides of the volcanic cone. Well-preserved cirques, glacial trough valleys, glacial threholds, polished surfaces of the glacial erratics and the moraine ridges indicate that several glaciation processes took place during the last glacial period in this region. Resuits of optically stimulated luminescence (OSL) dating on the moraine sediments, and the K/Ar, thermal ionization mass spectrometry (TIMS), electronic spinning resonance (ESR) dating on the volcanic rocks suggest two periods of glacier advances. One is named the Black Wind Mouth glacier advance taking place on the west and north slopes of the volcanic cone at an elevation of 2000-2100 m a.s.l., which is dated to about 20 ka, being the result of the Last Glacial Maximum (LGM). The other is named the Meteorological Station glacier advance at the elevation of 2400-2600 m a.s.l., dated to 11 ka during the late glacial period, and is tentatively correlated to the Younger Dryas stage. The scope of the former glacier advance is larger than that of the latter. Regional comparisons showed that the glacial sequences in the Changbai Mountains are similar to other glaciated areas in eastern Asia during the later part of the last glacial cycle.  相似文献   

14.
During the field work of the 1998~1999's and 1999~2000's Chinese National Antarctic Research Expedition (CHNARE) in the Grove Mountains, east Antarctica, some Cenozoic sedimentary debris are found in two terminal moraine banks over the blue ice near Harding Mount in the center of this region. All the debris are of characteristics of glaciogenic diamicton and belong to the products of the glacial movements of the East Antarctic Ice Sheet. In this paper, the authors make a detailed study on the sedimentary environments of the sedimentary debris through petrologic, sedimentological, mineralogical, and geo-chemical methods. Characteristics of their sedimentary textures and structures, grain size distributions, quartz grains' surface textures and features, together with their geo-chemical compositions all show that these sedimentary rocks are a kind of subglacial lodgement tills which are deposited in the ice sheet frontal area by reactions of glacial movements and glaciogenic melt water. Their palaeoenvironmental implications in revealing the retreat history of East Antarctic Ice Sheet are discussed. The authors draw the conclusion from current study that the glacial frontal of the East Antarctica Ice Sheet might have been retreated to this area during the Pliocene Epoch, which represents a warm climate event accompanied by a large-scale ice sheet retreat in Antarctica at that time.  相似文献   

15.
Discovery of Quaternary glacial evidence of Snow Mountain in Taiwan, China   总被引:4,自引:0,他引:4  
There are glacial remains of three different periods on the main peak of Snow Mountain in Taiwan province, including cirque lake, crosswall, polished surface, striation, moraine etc. These three different periods were called, respectively, Shanzhuang ((44.25 ±3.72) kaBP), Shuiyuan ((18.26 ±1.52) kaBP), and Xueshan glacial stages (the late period of last glaciation). It is characterized by the earlier glacier broad in scale.  相似文献   

16.
冰碛物年代及其环境变化   总被引:1,自引:0,他引:1  
冰碛物年代一直是冰川学研究的一个重要内容,也是环境变化深入研究的对象,冰川沉积物对于气候地层的建立起着不可忽视的作用。但是由于冰碛物自身与海洋、黄土等记录环境变化的内容相比存在局限性,所以造成对冰期划分,对比的不利。另外,自身年代缺乏也限制着全球冰期的划分与对比,笔者认为,目前的冰碛物研究对于气候地层起到了补充、验证的作用,在较大的时间尺度上是可行的,但是要提取高分辨率的环境变化信息,应该探索新的替代载体;同时要大力加强冰碛物绝对年代的研究。  相似文献   

17.
运用遥感数据和空间分析技术提取贺兰山高山林线,并结合DEM数据计算相关地形因子,采用相关分析和多元回归分析定量研究不同地形因子对高山林线分布高度的影响.结果表明,贺兰山高山林线上、下边界平均高度分别为3 106和3 022m,主山脊西侧山地高山林线上、下边界分布高度范围和平均高度比东侧略高.在山地两侧影响高山林线上边界高度的地形因子及其贡献率具有差异.南北朝向指数和地形指数对山地西侧高山林线上边界高度变化的相对贡献率分别为56.7%和43.3%;南北朝向指数、地形指数和坡度对东侧高山林线上边界高度变化的相对贡献率分别为50.9%、31.0%和18.1%.坡向是影响贺兰山高山林线分布高度的重要地形因素,而坡面凹凸程度和坡度对高山林线分布高度的影响与其他地形因素具有一定关系.  相似文献   

18.
雾灵山自然保护区胡桃楸种群结构特征分析   总被引:1,自引:0,他引:1  
胡桃楸群落是雾灵山自然保护区森林植被的典型类型之一,分布在海拔700~1 400 m的阳坡.根据雾灵山自然保护区胡桃楸种群不同龄级结构设置两个样地,通过对胡桃楸种群每木必测,采用种群径级结构代替年龄结构,不同的生境条件分析雾灵山自然保护区胡桃楸种群结构及动态变化特征.结果表明:(1)雾灵山自然保护区胡桃楸种群结构呈"金字塔"型,种群中幼树和中龄树所占比重大,表现为稳定型种群,种群个体数目基本随径级的增加而减少;(2)存活曲线接近Deevey-Ⅲ型,高径级种群趋于稳定,种群具两个死亡高峰,中龄树种群的死亡率高达80%,这是由于中龄树个体较多,在共同的生境条件下争夺生存空间和资源,群落树种互相竞争影响下,死亡率较高;(3)龄级分布与微地形的关系密切相关,坡度在30°~40°范围中胡桃楸种群龄级分布较广泛,海拔高度在800 m~1 000 m范围中胡桃楸种群各龄级分布广泛,幼树和中龄树数量多,而在其它海拔高度范围中受土地利用类型和生境条件的影响,分布的龄级数目少.  相似文献   

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