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1.
冰川沉积物成因确定的一种新方法 总被引：4，自引：1，他引：3
冰川沉积物的成因鉴定一直存在争论,尤其是体现在讨论第四纪冰川沉积物的成因确定问题方面,传统地质学从冰川沉积物的沉积学和地貌学特征方面来讨论其成因受到了挑战,本文试图从沉积砾石中寻找与冰川成因直接相关的应用信息,进而提出用砾石的声发射应力测量法确定其冰川成因的新认识,首先对现代冰川砾石进行声发射应力测量,将此测量值丙与 石所受的实际铅直应力值比较,研究显示二者对应很好,说明冰川砾石是能够记忆上覆冰层所造成的应力,其次,无争议的第四纪冰川砾石亦具有对应的应力记录,最后讨论了有争议的庐山地区第本四冰川沉积,研 相似文献
2.
冰川沉积物,尤其是第四纪冰川沉积物的成因鉴定一直存在争议,根据冰川沉积物的沉积学及地貌学特征来确定其是否冰川成因这一传统地质学方法,在中国东部受到了挑战。笔者利用砾石的声发射应力测量法(AE法)在冰川砾石中识别出与冰川作用直接相关的应力信息,从而对第四纪冰川沉积物的成因鉴定提供一种新的可靠方法。首先利用AE法对东昆仑山西大滩现代冰川砾石进行声发射应力测量,得到砾石的AE应力值,并将此值与砾石所承受的实际铅直应力计算值进行验证,发现二者吻合,证明冰川砾石是能够记忆上覆冰层所造成的应力。其次,在昆仑山垭口地区发育… 相似文献
3.
赤峰等地第四纪大陆冰川的地貌证据 总被引：2，自引：6，他引：2
近年来，中国赤峰等地相继发现第四纪冰川遗迹，为第四纪大陆冰川作用的重新讨论提供了新的地貌证据。这些证据主要有：冰臼、冰蚀残丘、古冰斗、刃脊和角峰等。冰臼的相继报道曾经引起“冰蚀成因”与“风蚀成因”的大讨论，而恰恰是这些引起争论的冰臼引发了笔者对中国境内第四纪大陆冰川的重新思考。经过近几年的实地考察研究，笔者认为：中国境内所报道的绝大部分“冰臼”确实是冰川作用的结果。其中，发现于中国北方花岗岩山脊上的冰臼是典型的大陆冰川作用的结果。内蒙古赤峰北部阿斯哈图石林是典型的冰蚀残丘，而花岗岩中与地面平行的“节理”——剥离面理与冰川作用是分不开的，其成因须重新讨论。冰臼与剥离面理的同时存在是冰川作用的重要标志之一。考虑到河北、山东、山西已经发现的第四纪冰川地貌特征，可以推论：华北东部地区曾经发育过第四纪大陆冰川，其范围可能达到山东的泰山以南，而全球更新世大冰盖的范围值得重新厘定。 相似文献
4.
北京市平原区下伏的泥砂砾石层发现较早,但对其成因一直存在着争议。本文通过对最新钻探资料的分析,经系统的古地磁样品测试,发现泥砂砾石层最早形成于上新世,距今约三百万年,这一时期的砾石层分布最广,厚度很大。此后更新世、全新世也有砾石层形成,但分布范围和厚度都显著减小。资料表明,上新世北京地区气候比较温暖湿润,不存在形成冰川沉积物的条件,此外第四纪的泥砾石层的分布和层位也与第四纪冰期的划分不能对应。北京市平原区下伏泥砂砾石层具有泥石流成因的基本特点,综合各种资料分析,应主要是洪水泥石流成因。 相似文献
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中国东部（105o E以东）第四纪冰川及其演化可为中国东部乃至东亚地区古气候环境重建提供基础信息及关键证据,正确认知冰川发育条件及正确运用冰川遗迹判别标准又是重建中国东部第四纪冰川及其演化的关键。中国东部中低山地第四纪期间冰川发育与否,即泛冰川论与有限冰川论的争议由来已久。近年来,山东与周边地区中低山及沿海丘陵带的“第四纪冰川”研究波澜再起。在系统地回顾中国东部第四纪冰川研究历史及新近出现争议的基础上,结合冰川发育条件、山地冰川地貌组合、判别原则与识别依据、中国东部数座中高山地存在无争议且形态清晰的冰川地形及其测年资料以及东亚古气候环境演化记录等得出：中国东部仅有台湾山地、长白山、贺兰山与太白山等数座主峰海拔超过2 500 m的中高山地保存有晚更新世以来的冰川作用地形。其余山地及海拔更低的丘陵带在第四纪期间任何一次冰川作用中均未达到与当时冰期气候相耦合的高度,不存在泛冰川作用。已报道的“冰川遗迹”皆为各种形似地质地貌现象的系统误判,其确切成因及环境意义有待深入探讨。 相似文献
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中国东部(105°E以东)第四纪冰川及其演化可为中国东部乃至东亚地区古气候环境重建提供基础信息及关键证据,正确认知冰川发育条件及正确运用冰川遗迹判别标准又是重建中国东部第四纪冰川及其演化的关键。中国东部中低山地第四纪期间冰川发育与否,即泛冰川论与有限冰川论的争议由来已久。近年来,山东与周边地区中低山及沿海丘陵带的"第四纪冰川"研究波澜再起。在较系统地回顾中国东部第四纪冰川研究历史及新近出现争议的基础上,结合冰川发育条件、山地冰川地貌组合、判别原则与识别依据、中国东部数座中高山地存在无争议且形态清晰的冰川地形及其测年资料以及东亚古气候环境演化记录等再次指出:中国东部仅有台湾山地、长白山、贺兰山与太白山等数座主峰海拔超过2 500 m的中高山地保存有晚更新世以来的冰川作用地形。其余山地及海拔更低的丘陵带在第四纪期间任何一次冰川作用中均未达到与当时冰期气候相耦合的高度,不存在泛冰川作用。已报道的"冰川遗迹"皆为各种形似地质地貌现象的系统误判,其确切成因及环境意义有待深入探讨。 相似文献
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笔者通过对宜兴县东岭水库中更新统剖面底砾层的特征阐述,从冰川的形成条件及剖面中砾石的特征分析,认为砾石层的成因为暴雨泥石流堆积;长江中下游地区第四纪以来并未发生过冰川作用。 相似文献
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中国西部现代冰川现象和第四纪冰川遗迹,露头清晰,保存完好,中外地学同人多肯定无疑,但对中国东部第四纪冰川遗迹,几十年来一直在争论着。这是由于多种地质因素相互交织,致使在识别它们的标志上产生了一定困难,有时令人困惑不解。不过只要我们认真观察、深入研究,中国东部第四纪冰川剥蚀和堆积的证据是很多的,且不难识别。作者野外工作经验表明,中国东部第四纪冰川遗迹是存在的。 相似文献
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第四纪冰川遗迹的判别标准与方法问题——兼论蒙山巨砾堆积堤之成因 总被引：2，自引：1，他引：1
判断中国东部中低山地冰川作用遗迹的真伪,只能通过科学实践检验和学术争鸣加以解决。利用实地考察所测数据资料,证明山东蒙山确无第四纪冰川遗迹。包括蒙山在内的山东中低山丘陵,迄今为止没有发现符合判别标准的末次冰期冰川地貌三要素组合。蒙山兰溪峡谷的谷形指数（0.07~0.24）与世界各地真正的冰川槽谷不符,被当作冰川证据的蒙山兰溪峡谷谷壁擦痕和拦马墙巨砾堆积堤砾石擦痕,不具有作为冰川地貌证据的唯一性或专属性,而是砾石沿河谷滚动、拖拽摩擦和撞击的结果。不连续、不对称分布于兰溪下游凹岸的拦马墙巨砾堆积堤,沿流向延伸或呈流线构造,具有平行主流的平顶、陡坡砾石堆和立石等景观,砾石的圆度、分选和砾组构造均指向泥石流堆积堤或特大洪水巨石边滩。它可能是1668年7月25日郯城大地震保存下来的群发性灾害遗迹。 相似文献
11.
ZHAO Zhizhong QIAO Yansong TIAN Jiaorong WANG Min LI Mingze HE Peiyuan QIAN Fang 《《地质学报》英文版》2006,80(5):754-758
How to effectively identify glacial sediments, especially Quaternary moraine, has been in dispute for decades. The traditional methods, e.g., sedimentary and geomorphologic ones, are facing challenge in eastern China where controversial moraine deposits are dominatingly distributed. Here, for the first time, we introduce the acoustic emission （AE） stress measurement, a kind of historical stress measurement, to identify Quaternary moraine. The results demonstrate that it can be employed to reconstruct stress information of glaciation remaining in gravels, and may shed light on the identification of Quaternary moraine in eastern China. First, we measured the AE stress of gravels of glacial origin that are underlying the Xidatan Glacier, eastern Kunlun Mountains in western China. Second, we calculated the stress according to the actual thickness of the glacier. The almost identical stress values suggest that the glacial gravels can memorize and preserve the overlying glacier-derived aplomb stress. And then we introduce this new approach to the controversial moraine in Mount Lushan, eastern China. The results indicate that the stress is attributed to the Quaternary glacier, and the muddy gravels in the controversial moraine in Mount Lushan are moraine deposits but not others. 相似文献
12.
Jessica M. Slomka Gregory M. D. Hartman 《Boreas: An International Journal of Quaternary Research》2019,48(1):215-235
The erosional nature of glacial systems commonly results in removal of direct evidence of previous glaciation (e.g. till and moraine). Therefore, reconstruction of former ice‐margin positions may rely, in part, on indirect (proxy) evidence from the sedimentary record. This study examines the facies and sedimentary architecture of a pre‐Middle Wisconsinan sand and gravel deposit (the ‘Grimshaw gravels’), which is positioned between areas where previous stratigraphical investigations have identified single (Late Wisconsinan) and multiple (pre‐Middle to Late Wisconsinan) glaciation by the Laurentide Ice Sheet. Five facies associations (FAs) are characterized within the deposit, which, together with the sedimentary architecture, record a transition from a braided river environment in the west (FA1‐3) to a gravelly braidplain delta front in the east (FA4 and 5). We propose that the Grimshaw gravels braid delta formed at the margin of a body of water that occupied the ancestral Peace River valley, probably impounded by the LIS; hence, the Grimshaw braid delta provides proxy evidence of the presence of an ice margin (previously unrecognized) in the Peace River lowland prior to the Middle Wisconsinan. This study provides further understanding of the origin of the Grimshaw gravels deposit, allowing re‐evaluation of previous models of formation. These findings offer insight into the glacial history of the southwestern margin of the LIS, and may help to refine ice‐sheet reconstructions spanning the Wisconsinan glaciation. 相似文献
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神农架是中国第四纪地质环境演变的热点地区之一。本文通过对第四纪冰川地貌、冰碛残迹及二者关系研究,提供了本区第四纪古冰川发育的多方面证据。神农架地区在第四纪时期曾发生三期冰期和两期冰缘期,即松柏冰期、木鱼坪冰期、龙潭冰期、松香坪冰缘期、神农架冰缘期。本文首次系统地建立了本区第四纪气候地层系列. 相似文献
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本文就如何重建第四纪古气候环境问题进行讨论。气候的演化和变更是环境系统中最重要的因素,第四纪冰川作用是反映这一因素中最为重要的事件之一。第四纪沉积物是古气候信息储存的主要场所,因此,系统地研究第四纪地层的地球物理特征、地球化学信息反馈、生物的演替等方面问题极为重要。在此基础上确定其地层的时间尺度、构造运动的程式,以及它们之间的相互关系,加以分析论证,建立起第四纪古气候环境的演化格局。 相似文献
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Timothy Kusky Liang Guo Shibao Xiang Xiaoyu Guo Xingyong Xu 《Journal of Asian Earth Sciences》2011,40(1):403-416
Accurately determining how far south Quaternary glaciers existed in eastern China has important implications for understanding global Quaternary climate. In this study, we provide evidence for a colder paleoclimate in the late Pleistocene of the Laoshan range on the eastern Shandong Peninsula at 36°05′–36°19′N latitude, through documentation of erosional and depositional landforms that were possibly formed by glaciation. We integrate field observations documenting and mapping the existence of typical glacial cirques, glacial horns, moraines, arêtes, tarn lakes, and other paleoglacial features in Mt. Laoshan, with a detailed digital elevation model (DEM) created in an ArcGIS environment, merged with Landsat ETM + imagery to document the spatial relations of these features. Other features that may or may not be glacial in origin include large boulder fields (that could be moraines or debris avalanches), and potholes (that could have formed beneath glaciers or in river systems). Additionally, some features previously interpreted as glacial features are here re-interpreted as weathering-related phenomena. Although some of these features alone provide only weak to moderate evidence for glaciation, together the suite of indicators provides strong evidence for sea-level glaciation at 36°N in the late Pleistocene of eastern China. We further integrate the evidence of glaciation with the late Pleistocene paleogeography and climate, and suggest that the glaciers formed as a result of orographic effects from moist monsoonal breezes crossing a paleolake developed in North China then rising over Mt. Laoshan and dropping their moisture there, with a wide desert formed on the leeward side of the mountains. 相似文献
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DUNCAN F. M. McGREGOR CHRISTOPHER P. GREEN 《Boreas: An International Journal of Quaternary Research》1978,7(4):197-203
Variability of composition and of pebble shape in river gravels are discussed. Catchment changes, progressive down-valley changes and less systematic cross-valley effects are recognized as sources of variability. Intercomponent ratios and pebble shape are analysed in the Pleistocene gravels of the Thames and its tributaries between High Wycombe and Hertford in England, and evidence of catchment change is identified. Glaciation on one or more occasions in the upper catchment of the Thames in the pre-Anglian Pleistocene is suggested to explain the high frequencies (>50 per cent) of far-travelled material in pre-Anglian gravels. The pattern of drainage development in the Vale of St. Albans at the time of the Anglian glaciation is also discussed 相似文献
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LEWIS A. OWEN RICHARD M. BAILEY EDWARD J. RHODES WISHART A. MITCHELL PETE COXON 《第四纪科学杂志》1997,12(2):83-109
This paper presents a revised glacial chronology for the Lahul Himalaya and provides the most detailed reconstruction of former glacier extents in the western Himalayas published to date. On the basis of detailed geomorphological mapping, morphostratigraphy, and absolute and relative dating, three glaciations and two glacial advances are constrained. The oldest glaciation (Chandra glacial stage) is represented by glacially eroded benches and drumlins (the first to be described from the Himalaya) at altitudes of >4300 m and indicates glaciation on a landscape of broad valleys that had minimal fluvial incision. The second glaciation (Batal glacial stage) is represented by highly weathered and disssected lateral moraines and drumlins representing two phases of glaciation within the Batal glacial stage (Batal I and Batal II). The Batal stage was an extensive valley glaciation interrupted by a readvance that produced superimposed bedforms. Optically stimulated luminescence (OSL) dating, indicates that glaciers probably started to retreat between 43400 ± 10300 and 36900 ± 8400 yr ago during the Batal stage. The Batal stage may be equivalent to marine Oxygen Isotope Stage 4 and early Oxygen Isotope Stage 3. The third glaciation (Kulti glacial stage), is represented by well-preserved moraines in the main tributary valleys that formed due to a less-extensive valley glaciation when ice advanced no more than 12 km from present ice margins. On the basis of an OSL age for deltaic sands and gravels that underlie tills of Kulti age, the Kulti glaciation is younger than 36900 ± 8400 yr ago. The development of peat bogs, having a basal age of 9160 ± 70 14C yr BP possibly represents a phase of climatic amelioration coincident with post-Kulti deglaciation. The Kulti glaciation, therefore, is probably equivalent to all or parts of late Oxygen Isotope Stage 3, Stage 2 and early Stage 1. Two minor advances (Sonapani I and II) are represented by small sharp-crested moraines within a few kilometres of glacier termini. On the basis of relative weathering, the Sonapani advance is possibly of early mid-Holocene age, whereas the Sonapani II advance is historical. The change in style and extent of glaciation is attributed to topographic controls produced by fluvial incision and by increasing aridity during the Quaternary. © 1997 John Wiley & Sons, Ltd. 相似文献
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《Boreas: An International Journal of Quaternary Research》2018,47(2):379-389
This is a synthesis of the glacial history of the northern Urals undertaken using published works and the results of geological surveys as well as recent geochronometric and remote sensing data. The conclusions differ from the classical model that considers the Urals as an important source of glacial ice and partly from the modern reconstructions. The principal supporting evidence for the conventional model – Uralian erratics found on the adjacent plains – is ambiguous because Uralian clasts were also delivered by a thick external ice sheet overriding the mountains during the Middle Pleistocene. Alternative evidence presented in this paper indicates that in the late Quaternary the Ural mountains produced only valley glaciers that partly coalesced in the western piedmont to form large piedmont lobes. The last maximum glaciation occurred in the Early Valdaian time at c. 70–90 ka when glacial ice from the Kara shelf invaded the lowlands and some montane valleys but an icecap over the mountains was not formed. The moraines of the alpine glaciation are preserved only beyond the limits of the Kara ice sheet and therefore cannot be younger than MIS 4. More limited glaciation during MIS 2 generated small alpine moraines around the cirques of the western Urals (Mangerud et al. 2008: Quaternary Science Reviews 27, 1047). The largest moraines of Transuralia were probably produced by the outlet glaciers of a Middle Pleistocene ice sheet that formed on the western plains and discharged across the Polar Urals. The resultant scheme of limited mountain glaciation is possibly also applicable as a model for older glacial cycles. 相似文献
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渐趋完善的第四纪冰川研究范式——记第四届中国第四纪冰川与环境变化研讨会 总被引：4，自引：1，他引：3
冰川是气候变化敏感的指示器,第四纪冰川研究在地球科学中占有重要的地位。2017年8月,第四届中国第四纪冰川与环境变化研讨会在兰州成功举办。与会专家认为,地貌学与沉积地层学的结合以及测年技术的发展,使中国第四纪冰期划分研究取得长足进展,不仅建立了80万年以来可与MIS进行比对的中国第四纪冰期与间冰期演化序列,还推动了中国第四纪环境变化研究的深入。通过研讨和交流,绝大多数专家认为中国东部中低山地某些疑似的第四纪冰川遗迹完全可以用非冰川成因予以解释,在今后的研究工作中应加强岩石地貌、气候地貌和外动力地貌过程的综合研究,尤其需要加强诸如颤痕等微观冰蚀地貌的分类、形成机制和环境意义研究。适时指出泛冰川论的缺陷和不足是本领域科学家的历史责任和使命担当,进一步开展具备科学事实、科学理论和科学观念的研究,从而完善中国第四纪冰川理论。建议国家级学会组织编制第四纪冰川遗迹调查与评价技术规范,加强全国高校自然地理学等相关专业的教师培训工作,同时加大冰川学、地貌学的科学普及力度。 相似文献