共查询到19条相似文献，搜索用时 140 毫秒
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庐山第四纪泥砾堆积物成因争论是庐山第四纪冰川争论的焦点之一。对新发现的庐山牧马场泥砾剖面进行了石英砂电镜扫描(SEM)和成因分析,并初步进行了电子自旋共振(ESR)年代测定。石英砂电镜扫描表明该剖面泥砾堆积物为冰川和流水共同作用形成,并在后期湿热化影响下导致部分化学特征明显;ESR测年数据表明该剖面形成于中更新世晚期(225.5±20)—(242.6±24)ka BP,与推测的时代(庐山冰期)基本一致。根据测试结果,作者认为庐山牧马场剖面具有第四纪冰川作用的痕迹,但其时代和规模尚有待探讨改进。 相似文献
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清江石门地区第四纪冰川沉积与岩溶发育期的探讨 总被引：2，自引：1，他引：1
通过对区内第四纪堆积物的研究,为本区岩溶发育期的划分提供了重要依据。丘顶第四纪冰川堆积物的确定,并结合邻近区域古气候环境演变特征,认为大姑-庐山间冰期是本区岩溶地貌基本格架的形成时期。古水文网与岩性是制约岩溶发育的主要因素。同时认为用地文期和阶地来划分岩溶发育期是不合适的。 相似文献
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庐山冰期是否存在一直是国内外学术界争论的话题,至今也无法定夺。大量争论文献,特别是“冰斗”“U形谷”形态、“冰碛”的粒径、网纹红土的分布、孢粉的分析及古气候等研究较为支持施雅风、李吉均等前辈的观点,庐山不存在第四纪冰川。本文根据2008年冻雨灾害现象,进行大胆推测,是否是极端气候造成了庐山冰期？超级丰富的过冷却水加上极其苛刻的暖锋逆温层条件形成了极强极长时期的冻雨,冻雨是滴雨成冰减少了从雪到冰的这一漫长过程,庐山“冰川”是否是在短时间内形成？ 相似文献
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中国第四纪冰川研究的回顾与展望 总被引：18，自引：3，他引：15
自从20世纪30年代李四光先生提出庐山和中国东部山地的第四纪冰期理论以来, 关于中国东部山地是否发生过第四纪冰川的问题困惑着国内外的地学工作者, 并为此展开了旷日持久的争论. 20世纪80年代, 经过大量的实地考察和室内分析工作, 在施雅风、崔之久和李吉均等撰写的<中国东部第四纪冰川与环境问题>一书中, 对中国东部第四纪冰川得到以下基本认识: 1)确认在中国东部有确切证据的古冰川遗迹仅在陕西太白山、吉林与朝鲜接壤的长白山、台湾的雪山和玉山等, 而在庐山及中国东部海拔2 000 m以下的山地在第四纪期间从来没有发生过冰川; 2)"泥砾"是"混杂堆积"的一种, 某些疑似的古冰川地形完全可以用其它非冰川成因予以解释, 所谓的冰川沉积多数情况下是季风气候条件下的古泥石流堆积; 3)中国东部第四纪环境发生过很大变化. 第四纪冰期中中国北方多年冻土南界向南扩展约10°, 到达长城一线, 中国东部地区年平均温度降低10～12 ℃. 喜冷动物群如猛犸与披毛犀则向南分布得更远, 到达长江口一带. 海平面下降约140 m, 古海岸远离现代海岸达600 km. 由于冬季风加强, 气候以干冷为主, 不利于冰川发育; 4)根据过去几十年的资料, 中、晚更新世中国西部山地发生过3～5次冰期, 但不存在统一的大冰盖. 因为青藏高原非常年轻, 只是在0.8 Ma BP之后才抬升到海拔3 000 m以上, 进入冰冻圈并发育冰川. 中国在全球变化研究特别是古全球变化研究中处于得天独厚的地位, 中国学者在黄土研究、青藏高原隆升、山地冰芯等方面已取得丰硕成果. 相似文献
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1934年，李四光来到江西庐山，看着眼前完美的U型谷、冰擦痕和冰臼，他彻底地被震撼了。这，就是存在了至少50万年的第四纪冰川啊。而在20世纪初，一些外国专家断言“中国绝不可能有第四纪冰川遗迹”。 相似文献
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李四光先生是我国老一辈地质学家之一,对地质学的许多分支学科作出了重要贡献。他建立了地质力学,并以发现中国第四纪冰川而闻名于世。我对1933年11月他在中国地质学会第十届年会上关于庐山第四纪冰川的理事长演说至今记忆犹新。作为一个科学家,他强调一个地质工作者首先要做好野外工作,一切地质假说和理论必须以事实为依据。作为新中国的第一任地质部部长,他鼓励地质工作者要为祖国的社会主义建设作出贡献。 相似文献
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论李四光教授的庐山第四纪冰川是对泥石流的误读 总被引：3，自引：1，他引：2
李四光教授1933年提出庐山存在第四纪冰川,是否确实,长期处于争论之中,争论的焦点在于庐山较广泛分布的泥砾混杂堆积到底是冰期冰碛还是泥石流堆积。笔者经多年研究得知:(1)牯岭站海拔1165m,现代气候记录告知,7月之气温必须下降20℃,处此高度的庐山才具备积雪成冰的条件,从而判断中纬度山地冰期降温无此可能;(2)沉积物特征包括砾石组成、砾径変化、基质组成、沉积结构、色泽、粘土矿物、擦痕特点等表明主要是泥石流堆积而非冰碛;(3)包围砾石的网纹红土与孢粉组成表明,沉积时期为暖温带—亚热带湿热环境,而并非寒冷冰川环境;(4)借助何培元等著作中古地磁年代以及高价铁与低价铁元素之比值推算古温度,如上述推算古温度的方法正确,就可推断李四光所定庐山冰期、大姑冰期、鄱阳冰期及何培元定的大排冰期基本上在中国西部与北半球处于间冰期的时段内,排除了具有积雪成冰川的可能性。李四光的学术误解及其社会名望导致中国东部第四纪冰川的研究走过了一段弯路。 相似文献
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自从第四纪初期后,地球各处的气候,有显著的剧烈变化,发生数次冰期和间冰期。李四光同志1922年在大同盆地和太行山东麓等地发现漂砾,以后又在庐山和附近发现冰川停积的泥砾,证实了中国第四纪冰川现象的存在。可是当时的一般地质学者,都未能同意。步达生认为中国的地位,在第四纪时代接近赤道,猿人因为气候的缘故而迁徙到中国。德日进由中国古代哺乳动物的鉴定和记载,强调 相似文献
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世界自然遗产黄龙钙华景观的地质分析 总被引：2，自引：0，他引：2
四川省松潘县黄龙是世界自然遗产,以秀美的自然景色、巨型的钙华堆积闻名于世.黄龙所处的岷山地区位于喜马拉雅期是构造活动地区,更新世以来不断隆起,成为现代隆起高山区.在更新世,山岳冰川广布全区,进入全新世,区内发育现代冰川,因而留下了冰蚀地貌和大量冰积物.黄龙的钙华来源于大气降水下渗形成的喀斯特水,该地下水以断层泉方式转为地表迳流,在沿沟向下流动过程中形成了钙华堆积,正是这种不断变化的钙华堆积呈现出绚丽的钙华风貌.钙华的堆积地貌有钙华池、钙华滩和钙华瀑布,溶蚀地貌有钙华洞穴,其钙华景观至今仍是处于不断变化中. 相似文献
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在前苏联中天山进行了两年的野外调查研究，利用所得资料，建立一个计算亚大陆型山地冰川物质－能量交换和冰川径流的模型。找出了控制这一地区现代冰川作用的主要冰川气候因素并使之定量化。计算了一地区冰川在全球水循环中的作用以及输入这一封闭水系的水气，即贮存在这一地区的水分占大气总水汽通量的份额。发现全球大气循环变化同冰川作用的相互影响。此外，重建了这一地区冰川３００年来物质平衡各分量。 相似文献
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Cosmic ray exposure ages of frost-weathered bedrock from mountain summits in the Outer Hebrides exceed the age of Late Devensian glaciation. Exposure ages of most glacially-abraded bedrock surfaces at low and intermediate elevations are younger than the age of maximum Late Devensian glaciation. These results confirm that previously mapped periglacial trimlines in the Outer Hebrides define the upper limit of bedrock erosion by Late Devensian ice. They are consistent with the interpretation, based on geomorphological evidence, that the trimlines mark the approximate upper limit of a Late Devensian Outer Hebrides Ice Cap. A postglacial exposure age from the summit of Oreval (662 m) suggests that this mountain was overrun during the last glaciation, indicating thicker ice cover and a lower surface gradient west of the ice-cap divide than previously inferred. Although bedrock surfaces below the trimlines are strongly ice-moulded, some show evidence of prior cosmic ray exposure, which we attribute to limited erosion during Late Devensian glaciation. If this interpretation is correct, the youngest apparent ages from these surfaces give the most reliable dates for deglaciation, at ca. 14.5–14 ka. This implies that ice persisted at favourable sites through the warm opening phase of the Windermere Interstade. Comparison with radiocarbon-dated evidence from offshore cores suggests net ice margin retreat of ∼74 km eastwards across the adjacent shelf in > 2.3 ± 1.0 ka. The dating evidence is consistent with relatively rapid retreat of calving margins to the coast, then slower withdrawal of ice margins to high ground. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Deglaciation of western Central Norway 总被引：4，自引：0，他引：4
JOHAN LUDVIG SOLLID LEIF SØRBEL 《Boreas: An International Journal of Quaternary Research》1979,8(2):233-239
The glacier movements and corresponding ice margins in Central Norway during Younger Dryas and Preboreal are reconstructed. Scattered, older marginal deposits are difficult to correlate. Raised beach features indicate that the deep fjords became ice-free at an early stage due to calving. In Møre og Romsdal county the glacier front lay at the fjord heads during Younger Dryas, with extensive local glaciation in the intervening mountain areas, and a limit of glaciation 500–600 m lower than the present. In certain places local moraines older than Younger Dryas have been preserved. Autochthonous block fields are widespread in the mountains of Møre og Romsdal. The lower limit of block fields lies at c. 500 m above sea level on the outermost coast and rises to c. 1500 m above sea level in the interior fjord country. No erratics, striation or lateral moraines from the inland ice have been found above this limit. Its gradient, which in outer fjord districts is about 1%, seems to indicate the ice surface at the last maximum of Weichsel glaciation. 相似文献
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沙鲁里山是研究第四纪冰川的最佳场所之一。可划分四个冰期,第一冰期为大陆冰盖,第二、三期及现代冰川为山岳冰川;整体反映第四纪地壳不断抬升,气候不断变暖,冰川不断向高山退缩的过程。 相似文献
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Alpine valley heads on the Antarctic Peninsula 总被引：1，自引：0，他引：1
Landform assemblages may be useful for elucidating glaciological changes in West Antarctica. Numerous nunataks in the Antaretic Peninsula are highly dissected by alpine valley heads (corries, cirque-headed valleys, etc.). It is believed that these have been cut by wet-based mountain glaciation before and during the build up of the ice-sheet. though the smallest ones may have formed later at times when the ice-sheet was insufficiently thick to submerge them. Dimensions of the features suggest that the main alpine glaciation was in the Miocene. Morphometric analysis of 1663 alpine valley heads has been based on satellite imagery, concentrating on regional variations in frequency, size and orientation. Length of alpine glaciation is believed to be an important control of size. Orientation is believed to have been influenced by palaeoclimate as well as topography. During early, more marginal glaciations poleward and lee-side sites were occupied by corrie glaciers, with more windward sites being added as glaciation intensified, followed by northerly orientations under more recent polar conditions. Comparisons have also been made with other morphometric studies of corries in Antarctica and elsewhere. 相似文献
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Jakob Heyman Arjen P. Stroeven Helena Alexanderson Clas Hättestrand Jon Harbor Yingkui Li Marc W. Caffee Liping Zhou Daniel Veres Feng Liu Martin Machiedo 《第四纪科学杂志》2009,24(7):710-727
Key locations within an extensive area of the northeastern Tibetan Plateau, centred on Bayan Har Shan, have been mapped to distinguish glacial from non‐glacial deposits. Prior work suggests palaeo‐glaciers ranging from valley glaciers and local ice caps in the highest mountains to a regional or even plateau‐scale ice sheet. New field data show that glacial deposits are abundant in high mountain areas in association with large‐scale glacial landforms. In addition, glacial deposits are present in several locations outside areas with distinct glacial erosional landforms, indicating that the most extensive palaeo‐glaciers had little geomorphological impact on the landscape towards their margins. The glacial geological record does indicate extensive maximum glaciation, with local ice caps covering entire elevated mountain areas. However, absence of glacial traces in intervening lower‐lying plateau areas suggests that local ice caps did not merge to form a regional ice sheet on the northeastern Tibetan Plateau around Bayan Har Shan. No evidence exists for past ice sheet glaciation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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EILIV LARSEN ROLF SANDVEN HÅKON HEYERDAHL SIGRUN HERNES 《Boreas: An International Journal of Quaternary Research》1995,24(1):37-46
Bottomsets from glaciomarine deltas situated stratigraphically below and above the Weichselian maximum glaciation till at Skorgenes, western Norway, were tested for consolidation in an attempt to quantify the ice thickness at the time of deposition of the till. The value of the preconsolidation pressure in the lower unit (15 ± 1 MPa), indicates an ice thickness over the site of some 1350 ± 90 m. This is, however, only considered a minimum because values of preconsolidation pressures normally are lower than actual ice thickness would suggest due to incomplete drainage of the bed during consolidation. The estimated ice thickness indicates an ice surface some 400 m above the lower limit of the block field in the area, suggesting that this limit can not be used as a criterion for reconstructing the upper glacier surface for the Weichselian maximum glaciation in western Norway. Also, the nearest mountain peaks seemingly were completely ice covered, suggesting that no nunataks were present in that area. 相似文献
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G. F. Ufimtsev 《Russian Journal of Pacific Geology》2008,2(1):87-96
The morphological structure of mountains forming under conditions of extensive continental and mountain glaciation is described. They are characterized by a general hummocky profile with alternating dome-shaped summits, steps, valley-shaped depressions, and microrelief represented by roche moutonées, greywethers, and nunataks with isolated peaks in the form of high cones and prisms. The under-ice mountains are represented by a step morphological landscape with glacial steps and leveling surfaces. The step pattern of their morphological landscape is assumed to be related to successive layering of ice according to its movement velocity and the formation of a jet current against the background of general dominant displacements of ice masses. This makes under-ice mountains morphologically similar to medium-height and low mountainous relief of the temperate humid belt in the Northern Hemisphere with dominant landslides on their slopes. 相似文献