Extent and chronology of Quaternary glaciation

In a recent INQUA project the extent of Pleistocene glaciations has been digitally mapped and the chronology of events reviewed. The onset of the present Ice Age in both hemispheres dates back to the Palaeogene. In Greenland, Iceland, North America and southernmost South America sizeable ice sheets formed well before 2.6 ka BP. In Alaska and on Tierra del Fuego the ice advanced further than in any later glaciations. Evidence for Early Pleistocene glaciation （2.6-0. 78 Ma） has been reported from many parts of the world, but in most cases dating remains problematic, and the size of the glaciers and ice sheets is unknown.     

昆仑山垭口地区第四纪冰川遗迹及冰期演化

基于成因-环境原则和多指标综合原则,依据昆仑山垭口地区的冰川地貌特征、冰碛物特征和孢粉信息,重建了该地区古环境演化历史。其中,冰碛物中的石英砂扫描电镜结果揭示了冰川、流水、风等地质营力对冰碛物的影响,孢粉分析结果在一定程度上可以恢复当时的植被类型。根据垭口冰碛ESR年龄280 ka B.P.和冰碛剖面特征,将其时代暂定为300~260 ka B.P.;根据纳赤台地区的冰川地貌和沉积物特征,确定纳赤台后沟沉积为冰水扇沉积,纳赤台冰期为600~400 ka B.P.;根据玉虚峰U形谷两道侧碛垄的ESR和OSL年龄将其时代暂定为末次冰期早-中期。结合前人的研究成果,将昆仑山垭口地区的冰期序列厘定为望昆冰期（700~500 ka B.P.）、纳赤台冰期（600~400 ka B.P.）、垭口冰期（300~260 ka B.P.）、玉虚峰冰期（115~44 ka B.P.）、本头山冰期（20~13 ka B.P.）。     

Quaternary glaciation of Mt. Qomolangma-Xixabangma region

The uplift of the Himalaya and Qinghai-Xizang plateau began at the end of Pliocene to the beginning of Early Pleistocene, changing the atmospheric circulation in Asia, enhancing the South Asian monsoon and enormously effecting the climatic conditions and glacial development.According to the evidence of glacial deposits, geomorphology, paleobiology, paleopedology, etc., at least four glaciations can be recognized. The uplift of the Himalayas was earlier than that of other mountains, so that the glaciation occurred in Early Pleistocene, forming small piedmont glaciers on the N slope, whilst at the same time there were wide short valley glaciers on the S slope. During the Middle Pleistocene, the height of Himalaya was about 4000 m a s l, the monsoon was strong, and much water vapour reached the interior of the plateau, the most favourable period for glacial development. Great piedmont glaciers and small ice caps formed on the mountains N of Himalayas and great valley glaciers occurred on the S slope, but no great ice sheet covered the plateau.During the early Late Pleistocene, the Himalayas had risen to over 5000 m asl, forming a barrier against the incursion of the Indian monsoon, so that the precipitation decreased sharply on the plateau N of Himalayas, thus diminishing the extent of the glaciation. But on the high mountains of the S part of Xizang and on several high mountains of the S slope of the Great Himalaya, the precipitation increased and the extent of glaciation reached a maximum. Since Last Glaciation, the precipitation of the alpine zone has decreased more sharply, the climate has become drier and colder, becoming unfavourable for glacial development.During the Holocene, three stages may be distinguished, i.e. the recession in Early Holocene (10,000-8000 BP); the disappearance of most glaciers in the Hypsithermal period in Middle Holocene, (8000-3000 BP); and the neoglacial fluctuations in Late Holocene (3000 BP up to present). The glaciers of the Neoglaciation advanced several hundred meters or even 3–5 km farther than existing glaciers.     

Quaternary glaciation of the Bale Mountains,Ethiopia

Central Ethiopia comprises a high plateau at 2000–3000 m, formed from Tertiary lava flows and bisected by the Eastern African Rift. Ten volcanic mountains rise to altitudes of just over 4000 m, but on only three has Quaternary glaciation been substantiated by published field observations. On the Bale Mountains (4400 m), a previous report based on limited evidence proposed an ice‐cap extending to 600 km². Based on aerial photographs and ground surveys, this paper reports evidence of a more complex situation. A wide spread of large erratic boulders on the plateau records a central ice cap of 30 km², though ice probably extended for a further 40 km². Further north two groups of deeply incised and clearly glaciated valleys contain moraines and roches moutonnées (60 km²). On interfluves between them and on the open north slopes are moraines from an earlier stage of the same glaciation or from a distinct older event. Altogether about 180 km² may have been glaciated. Cores dated by ¹⁴C from inside and outside the glaciated area suggest that at least the northern valley glaciers may date from the Last Glacial Maximum. Estimated equilibrium line altitudes for these glaciers and the ice‐cap are 3750–4230 m. Copyright © 2005 John Wiley & Sons, Ltd.     

Quaternary glaciation of the North Slope of Karakorum mountains

Three kinds of moraines can be found in the Muztagh valley on the N slope of Mount K2, Karakorum: an old calco-cement moraine lying at the altitude of 5000 m asl, a hilly moraine lying at the altitude of 4200–4800 m asl and a new lateral moraine, lying on both sides of the present river valley. According to the moraines’ geomorphology, they are referred to the Middle Pleistocene Glaciation, the Late Pleistocene Glaciation and the Post-Glacial Period respectively. The lowest level of glacial cirques at 4200–4000 m asl, corresponding to the largest Glaciation, belongs to the Middle Pleistocene (Riss). The ancient cirques at this altitude in the Shaksgam and Yargand valleys are poorly preserved while at the piedmont of the West Kunlun mountains they are represented in better shape. This means that these ancient cirques had been submerged and almost removed by the main ice flow of the valleys. Old cirques, however, are well shaped (or reshaped) where associated with younger cirques at 4600 m als; they could be considered as the product of the Last Glaciation (Würm). Thus, the equilibrium line altitude (ELA) decreased to 1600 m during the Riss Glaciation and to 1000 m during the Würm Glaciation. On the basis of the ELA decrease and existence of complex morainic deposits found at the piedmont of the West Kunlun mountains at about 2200 m asl, the author adheres to the opinion that Riss Glaciation had developed an ice cover (ice sheet), with the central ice area located in Karakorum and reaching up to the high peaks of the Kunlun mountains, and down to the piedmont region. During the Last Glaciation an immense ice cap covered the upper parts of the Shaksgam and Yarkant valleys. The paper also deals with the relations between glaciations and tectonic uplift, indicating that topographic and climatic conditions were favourable for the large-scale ice development in the Middle and Late Pleistocene. The uplift may have reached 600–800 m during the Postglacial period. The uplift rates are often reflected by the glaciostatic in the Postglacial Age.     

Late Quaternary glaciation in the south-western Barents Sea

Moraine ridges have been morphologically and seismically identified in the south-western Barents Sea. Some of these ridges were deposited in front of ice lobes from the northern part of the Fennoscandian Ice Sheet, others in front of glaciers located on the southern Barents Sea shelf. The moraine ridges were probably deposited during the Weichselian, possibly the Late Weichselian.     

Late Quaternary glaciation of the Cordillera Real,Bolivia

Glacial geological studies in tropical mountain areas of the Southern Hemisphere can be used to address two issues of late Pleistocene climate change: the global synchroneity of deglaciation and the magnitude of temperature reduction in the tropics. Radiocarbon dates from the Cordillera Real and from other areas in Perú and Bolivia suggest that late Pleistocene glaciation culminated between 14 000 and 12 000 yr BP, followed by rapid deglaciation. Because deglaciation was apparently synchronous with that in Northern Hemisphere regions, insolation change at high latitudes may not have been the only factor that produced global deglaciation at this time. Late Pleistocene glaciation in the Cordillera Real culminated when precipitation was 200 mm yr^?1 higher and temperatures were 3.5° ±1.6°C lower than today; this produced an equilibrium-line altitude depression of about 300 ± 100 m on the western side of the cordillera. Prior to this, conditions were drier and probably at least as cold. However, the lack of moraines in the Cordillera Real dated to the Last Glacial Maximum (ca. 18000 yr BP) precludes using the equilibrium-line altitude method to quantitatively evaluate the discrepancy between warm sea-surface temperatures and cold terrestrial conditions reconstructed with other proxies for this time period.     

Late Quaternary glaciation of Tibet and the bordering mountains: a review

Abundant glacial geologic evidence present throughout Tibet and the bordering mountains shows that glaciers have oscillated many times throughout the late Quaternary. Yet the timing and extent of glacial advances is still highly debated. Recent studies, however, suggest that glaciation was most extensive prior to the last glacial cycle. Furthermore, these studies show that in many regions of Tibet and the Himalaya glaciation was generally more extensive during the earlier part of the last glacial cycle and was limited in extent during the global Last Glacial Maximum (marine oxygen isotope stage 2). Holocene glacial advances were also limited in extent, with glaciers advancing just a few kilometers from their present ice margins. In the monsoon-influenced regions, glaciation appears to be strongly controlled by changes in insolation that govern the geographical extent of the monsoon and consequently precipitation distribution. Monsoonal precipitation distribution strongly influences glacier mass balances, allowing glaciers in high altitude regions to advance during times of increased precipitation, which are associated with insolation maxima during glacial times. Furthermore, there are strong topographic controls on glaciation, particular in regions where there are rainshadow effects. It is likely that glaciers, influenced by the different climatic systems, behaved differently at different times. However, more detailed geomorphic and geochronological studies are needed to fully explore regional variations. Changes in glacial ice volume in Tibet and the bordering mountains were relatively small after the global LGM as compared to the Northern Hemisphere ice sheets. It is therefore unlikely that meltwater draining from Tibet and the bordering mountains during the Lateglacial and early Holocene would have been sufficient to affect oceanic circulation. However, changes in surface albedo may have influenced the dynamics of monsoonal systems and this may have important implications for global climate change. Drainage development, including lake level changes on the Tibetan plateau and adjacent regions has been strongly controlled by climatic oscillations on centennial, decadal and especially millennial timescales. Since the Little Ice Age, and particularly during this century, glaciers have been progressively retreating. This pattern is likely to continue throughout the 21st century, exacerbated by human-induced global warming.     

Recognition and palaeoclimatic implications of late Quaternary niche glaciation in eastern Lesotho

Geomorphic evidence of former glaciation in the high Drakensberg of southern Africa has proven controversial, with conflicting glacial and non‐glacial interpretations suggested for many landforms. This paper presents new geomorphological, sedimentological and micromorphological data, and glacier mass‐balance modelling for a site in the Leqooa Valley, eastern Lesotho, preserving what are considered to be moraines of a former niche glacier that existed during the Last Glacial Maximum (LGM). The geomorphology and macro‐sedimentology of the deposits display characteristics of both active and passive transport by glacial processes. However, micromorphological analyses indicate a more complex history of glacial deposition and subsequent reworking by mass movement processes. The application of a glacier reconstruction technique to determine whether this site could have supported a glacier indicates a reconstructed glacier equilibrium line altitude (ELA) of 3136 m a.s.l. and palaeoglacier mass balance characteristics comparable with modern analogues, reflecting viable, if marginal glaciation. Radiocarbon dates obtained from organic sediment within the moraines indicate that these are of LGM age. The reconstructed palaeoclimatic conditions during the LGM suggest that snow accumulation in the Drakensberg was significantly higher than considered by other studies, and has substantial relevance for tuning regional climate models for southern Africa during the last glacial cycle. Copyright © 2009 John Wiley & Sons, Ltd.     

Late Quaternary glaciation in Southern Africa: moraine ridges and glacial deposits at Mount Enterprise in the Drakensberg of the Eastern Cape Province,South Africa

Late Quaternary moraines and diamictons containing striated clasts are described from near Elliot in the Drakensberg of South Africa. An equilibrium line altitude (ELA) of 2109 m is suggested for the palaeoglacier associated with the innermost moraine. This glacier was fed by a very extensive snowblow area and the ELA may reflect the temperature–precipitation–wind ELA rather than the temperature–precipitation ELA and be considerably below the ‘regional’ ELA. Mean annual air temperatures when glaciation occurred were probably at least 10.0°C below those of the present. Copyright © 2001 John Wiley & Sons, Ltd.     

Late Quaternary glaciation history of Isla de los Estados,southeasternmost South America

Isla de los Estados is a mountainous island southeast of Tierra del Fuego, in southernmost South America. Its central and eastern parts have an alpine topography, transected by U-shaped valleys, small, partly over-deepened fjords, and a multitude of abandoned cirques, all associated with extensive former local glaciations. Traces of glacial erosion generally reach 400–450 m a.s.l., and above that trimline a distinct sharp-edged nunatak derived landscape is present. The westernmost part of the island has a lower, more subdued topography, reflecting its “softer” geology but possibly also over-running and erosion by mainland-derived ice streams. The present study concentrated on glacigenic sediment sequences exposed along coastal erosional cliffs. A combination of OSL and ¹⁴C datings show that these sediments mostly date from the latest (Wisconsinan/Weichselian) glacial cycle, i.e. from the last ca. 100 ka with the oldest (glaciolacustrine) deposits possibly as old as 90–80 ka. The upper parts of overlying tills, with associated lateral and terminal moraines from glaciers that expanded onto an eustatically exposed dry shelf north of the island, date from the last global glacial maximum (LGM). Radiocarbon ages of peat and lake sediments indicate that deglaciation began 17–16 cal ka BP.     

Late Quaternary glaciation of the northern Urals: a review and new observations

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.     

Late Quaternary relative sea-level changes and the role of glaciation upon continental shelves

Sea levels of the past 20 kyr are largely determined by the response of the Earth to the last ice age. Consequently, sea-level indicators are an important source of information about the interaction between cryosphere and hydrosphere and the solid Earth. Based on the material presented at a recent European Science Foundation conference, the present paper pin-points some of the topics currently under discussion with respect to sea-level evidence found on continental shelves. These topics include possible effects of erosion and changes in palaeotidal ranges on indicators of former relative sea levels as well as the problems involved in the determination of palaeo-water depth in addition to former sea levels. More evidence is being gathered for substantial small-scale patterns in the sea-level changes at or nearby to the former ice margins. These patterns are not reproduced by the available geophysical models, which reconcile on first-order level only the large-scale pattern.     

庐山第四纪冰川遗迹的新发现及初步研究

概叙了庐山第四纪冰川遗迹中的新发现,并在此基础上作了初步研究,得出在分析和研究庐山地貌和第四纪堆积时,应注意多种特征的集合。     

青藏高原第四纪冰川的早期记录及其构造与气候含义

综合青藏高原第四纪冰川早期记录的研究进展和典型盆地地层、沉积、古生物、古环境研究的系统成果,扎达盆地香孜组上部冻融层的出现代表了区域的古海拔达到了高原冰缘的高度,即3 500 m以上.这一段地层的时代可能从2.3 Ma前后开始.并与贡巴砾石层下部冰水沉积层的时代基本一致.卓奥友冰期和希夏邦马冰期的时代与扎达盆地沉积结束后,直接覆盖其上的终碛垄和冰碛垄的时代大致相当,展现了这一时期喜马拉雅山脉的山岳冰川进一步发育,也说明喜马拉雅山脉作为青藏高原海拔最高的地区开始冰冻圈的环境很可能在早更新世早中期.川西地区的早更新世的冰川沉积说明东喜马拉雅构造结附近地区这一时期已经抬升至冰冻圈高度,但是,海拨高度与气候环境与喜马拉雅山脉应有不同.具体的时代仍需要深入工作.青藏高原普遍开始冰冻罔记录是在中更新世早期.伴随着全球冰期的到来,这一时期的冰川作用在青藏高原最为发育和广泛.这些暗示着青藏高原在中更新世早期整体性地较快速抬升进入冰冻圈,即海拔3 500 m以上.详细的过程仍有待深入研究.     

Late Quaternary glaciation in the Nun‐Kun massif,northwestern India

The late Quaternary glacial history of the Nun‐Kun massif, located on the boundary between the Greater Himalaya and the Zanskar range in northwestern India, was reconstructed. On the basis of morphostratigraphy and ¹⁰Be dating of glacial landforms (moraines and glacial trimlines), five glacial stages were recognized and defined, namely: (i) the Achambur glacial stage dated to Marine Oxygen Isotope Stage 3 to 4 (38.7–62.7 ka); (ii) the Tongul glacial stage dated to the early part of the Lateglacial (16.7–17.4 ka); (iii) the Amantick glacial stage dated to the later part of the Lateglacial (14.3 ka, 11.7–12.4 ka); (iv) the Lomp glacial stage dated to the Little Ice Age; and (v) the Tanak glacial stage, which has the youngest moraines, probably dating to the last few decades or so. Present and former equilibrium‐line altitudes (ELAs) were calculated using the standard area accumulation ratio method. The average present‐day ELA of ～4790 m above sea level in the Greater Himalaya is lower than those in the Ladakh and Zanskar ranges, namely 5380 and ～5900 m a.s.l., respectively. The ELA in the Zanskar range is higher than in the Ladakh range, possibly due to the higher peaks in the Ladakh range that are able to more effectively capture and store snow and ice. ELA depressions decrease towards the Ladakh range (i.e. inner Plateau). Peat beds interbedded with aeolian deposits that cap the terminal moraine of Tarangoz Glacier suggest millennial‐time‐scale climate change throughout the Holocene, with soil formation times at c. 1.5, c. 3.4 and c. 5.2 ka, probably coinciding with Holocene abrupt climate change events. Given the style and timing of glaciation in the study area, it is likely that climate in the Nun‐Kun region is linked to Northern Hemisphere climate oscillations with teleconnections via the mid‐latitude westerlies.     

Postglacial emergence and Late Quaternary glaciation on northern Novaya Zemlya, Arctic Russia

Recent observations on postglacial emergence and past glacier extent for one of the least accessible areas in the Arctic, northern Novaya Zemlya are here united. The postglacial marine limit formed 5 to 6 ka is registered on the east and west coasts of the north island at 10 ± 1 and 18 ± 2 m aht, respectively. This modest and late isostatic response along with deglacial ages of >9.2 ka on adjacent marine cores from the northern Barents Sea indicate either early (>13 ka) deglaciation or modest ice sheet loading (<1500 m thick ice sheet) of Novaya Zemlya. Older and higher (up to 50 m aht) raised beaches were identified beneath a discontinuous glacial drift. Shells from the drift and underlying sublittoral sediments yield minimum limiting ¹⁴C ages of 26 to 30 ka on an earlier deglacial event(s). The only moraines identified are within 4 km of present glacier margins and reflect at least three neoglacial advances in the past 2.4 ka.     

Rb/Sr geochronology of granites and gneisses from the Mount Everest region,Nepal Himalaya

Nineteen samples of granites, orthogneisses and paragneisses from the High Himalaya basement nappe(s) of the Mount Everest region have been dated by the Rb/Sr method. The post-metamorphic tourmaline leucogranites of the upper Imja Drangka (Nuptse, Lhotse Glacier) have high initial Sr⁸⁷/Sr⁸⁶ characteristic of an anatectic origin from crustal material. A whole-rock isochron age of 52 m. y. (Early Eocene) has been obtained for the samples from the granite body of Lhotse Glacier; apparently Sr isotopic homogenization was not reached throughout the much larger Nuptse granite. The granite precursor of the migmatitic orthogneisses from the upper Dudh Kosi valley has an age of 550 ± 16 m. y. (whole rock isochron) and a high initial Sr⁸⁷/Sr⁸⁶ ratio indicating its origin from an older basement complex. The Rb/Sr data on paragneisses from the south face of Lhotse do not define an isochron, possibly reflecting isotopic hetero-geneity in the sedimentary protoliths and incomplete homogenization during a late Precambrian metamorphism. All the mineral ages fall in the time span from 15 to 17 m. y. They represent cooling ages reflecting a regional phase of major uplift in the Middle Miocene and post-dating the peak of the Himalayan metamorphism which the data from the Mt. Everest region place in pre-Eocene times.     

Quaternary glaciation in the Nubra and Shyok valley confluence, northernmost Ladakh, India

Three glacial stages (Deshkit 1, Deshkit 2 and Dishkit 3 glacial stages) are identified in the Nubra and Shyok valleys in northernmost Ladakh, northwest India, on the basis of geomorphic field mapping, remote sensing, and ¹⁰Be terrestrial cosmogenic nuclide surface exposure dating. The glacial stages date to ∼ 45 ka (Deshkit 1 glacial stage), ∼ 81 ka (Deshkit 2 glacial stage) and ∼ 144 ka (Deshkit 3 glacial stage). A mean equilibrium line altitude depression of ∼ 290 m for the Deshkit 1 glacial stage was calculated using the area accumulation ratio, toe-to-headwall ratio, area-altitude, and area-altitude balance ratio methods. Comparison of glaciation in the Nubra and Shyok valleys with glaciations in the adjacent Central Karakoram of northern Pakistan and northern side of the Ladakh Range of northern India indicates that glaciation was synchronous on Milankovitch timescales across the region during MIS-6, but differed greatly in extent, with more extensive glaciation in the Karakoram than the morphostratigraphically equivalent glaciation on the northern slopes of the Ladakh Range. This highlights the strong contrast in the extent of glaciation across ranges in the Himalaya-Tibetan orogen, necessitating caution when correlating glacial successions within and between mountain ranges.     

云南玉龙雪山第四纪冰期与冰川演化模式

云南玉龙雪山高峰区有现代冰川１９条,面积１１．６１Ｋｍ＾２,冰川融水汇入金沙江。在现代冰川外围有丰富的古冰川遗迹,可划分３次更新世冰期,即大理、丽江和云杉枰冰期。相当于欧洲阿尔卑斯的玉木里斯和民德冰期。其中以丽江冰期冰川规模最大,当时,河水冰期的白水河冰川长２．５Ｋｍ,冰川 演化模式与梅里雪山、贡嘎山东坡相同,均属藏东南型,而与青藏高原广大高山区以例数第三次冰不川最大规模有别。主要是它们位于青藏高