The Pleistocene Glaciation in the KarakoramMountains： Reconstruction of Past Glacier Extensions and Ice Thicknesses

Geomorphological and Quaternarygeological field- and laboratory data (Fig.1) are introduced and interpreted with regard to the maximum Ice Age (LGM) glaciation of the Central and South Karakoram in the Braldu-, Basna-, Shigar and Indus valley system as well as on the Deosai plateau between the Skardu Basin and the Astor valley (Fig.2). These data result from two research expeditions in the years 1997 and 2000. They show that between c. 6o and 2o Ka the Central Karakorum and its south slope were covered by a continuous c. 125000 km^2 sized ice stream network. This ice stream network flowed together to a joint parent glacier, the Indus glacier. The tongue end of the Indus glacier reached down to 850 ～ 800m a.s.l. In its centre the surface of this Indus ice stream network reached a height of a good 6ooo m. Its most important ice thicknesses amounted to c. 2400 ～ 2900 m.     

Relict glacial landscape in the Sierra Baguales Mountain Range(50°-51° S): evidence of glaciation dynamics and types in the eastern foothills of the southern Patagonian Andes

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range(SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field(SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift,which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum(LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower elevations.This can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26m Equilibrium Line Altitude(ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio(AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.     

Glacier changes in the eastern Nyainqêntanglha Range of Tibetan Plateau from 1975 to 2013

Maritime-type glaciers in the eastern Nyainqêntanglha Range, located in the southeastern part of the Tibetan Plateau, are an important water source for downstream residents and ecological systems. To better understand the variability of glaciers in this region, we used the band ratio threshold(TM3/TM5 for the Landsat TM /ETM+ and TM4/TM6 for Landsat OLI) to extract glacier outlines in ~1999 and ~2013. After that, we also generated a series of glacier boundaries and monitored glacier variations in the past 40 years with the help of the Chinese Glacier Inventory data(1975) and Landsat TM, ETM+ and OLI data. The total glacier area decreased by 37.69 ± 2.84% from 1975 to 2013. The annual percentage area change(APAC) was ~1.32% a-1 and ~1.29% a-1 in the periods 1975-1999 and 1999-2013, respectively. According to the lag theory, the reaction time is probably about 10 years and we discuss the variations of temperature and precipitation between 1965 and 2011. Temperature and precipitation increased between 1965 and 2011 at a rate of 0.34°C /10 a and 15.4 mm/10 a, respectively. Extensive meteorological data show that the glacier shrinkage rate over the period may be mainly due to increasing air temperature, while the increasing precipitation partly made up for the mass loss of glacier ice resulting from increasing temperature may also lead to the low APAC between 1999 and 2013. The lag theory suggests that glacier shrinkage may accelerate in the next 10 years. Small glaciers were more sensitive to climate change, and there was a normal distribution between glacier area and elevation. Glaciers shrank in all aspects, and south aspects diminished faster than others.     

Modeling the Roles of Precipitation Increasing in Glacier Systems Responding to Climate Warming —— Taking Xinjiang Glaciated Region as Example

The studies on prediction of climate in Xinjiang almost show that the precipitation would increase in the coming 50 years, although there were surely some uncertainties in precipitation predictions. On the basis of the structure of glacier system and nature of equilibrium line altitude at steady state （ELAo）, a functional model of the glacier system responding to climate changes was established, and it simultaneously involved the rising of summer mean temperature and increasing of mean precipitation. The results from the functional model under the climatic scenarios with temperature increasing rates of 0.01, 0.03 and 0.05 K/year indicated that the precipitation increasing would play an evident role in glacier system responding to climate change： if temperature become 1 ℃ higher, the precipitation would be increased by 10%, which can slow down the glaciers retreating rate in the area by 4 %, accelerate runoff increasing rate by 8 % and depress the ELAo rising gradient by 24 m in northern Xinjiang glacier system where semi-continental glaciers dominate, while it has corresponding values of only 1%, 5 % and 18m respectively in southern Xinjiang glacier system, where extremely continental glaciers dominate.     

Critical Approach to Methods of Glacier Reconstruction in High Asia and Discussion of the Probability of a Qinghai-Xizang （Tibetan） Inland Ice

This overview discusses old and new results as to the controversy on the past glacier extension in High Asia, which has been debated for 35 years now. This paper makes an attempt to come closer to a solution. H.v. Wissmann's interpretation (1959) of a small-scale glaciation contrasts with M. Kuhle's reconstruction (1974) of a large-scale glaciation with a 2.4 million km2 extended Qinghai-Xizang (Tibetan) inland glaciation and a Himalaya-Karakorum icestream network. Both opinions find support but also contradiction in the International and Chinese literature (Academia Sinica). The solution of this question is of supraregional importance because of the subtropical position of the concerned areas. In case of large albedo-intensive ice surfaces, a global cooling would be the energetical consequence and, furthermore, a breakdown of the summer monsoon. The current and interglacial heat-low above the very effective heating panel of the Qinghai-Xizang (Tibetan) Plateau exceeding 4000 m, which gives rise to this monsoon circulation, would be replaced by the cold-high of an inland ice. In addition, the plate-tectonically created Pleistocene history of the uplift of High Asia — should the occasion arise up to beyond the snowline (ELA) —would attain a paleoclimatically great, perhaps global importance. In case of a heavy superimposed ice load, the question would come up as to the glacio-isostatic interruption of this primary uplift. The production of the loesses sedimentated in NE-China and their very probable glacial genesis as well as an eustatic lowering of the sea-level by 5 to 7 m in the maximum case of glaciation are immediately tied up with the question of glaciation we want to discuss. Not the least, the problems of biotopes of the sanctuary-centres of flora and fauna, i.e., interglacial re-settlement, are also dependent on it. On the basis of this Quaternary- geomorphological-glaciological connection, future contributions are requested on the past glaciation, the current and glacial permafrost table and periglacial development, the history of uplift, and the development of Ice Age lakes and loess, but also on the development of vegetation and fauna in High Asia.     

Half-a-century(1971–2020) of glacier shrinkage and climatic variability in the Bhaga basin,western Himalaya

Glacier shrinkage is a globally occurring phenomena.High-resolution change detection based on frequent mapping and monitoring of high-altitude glaciers is necessary to precisely evaluate future water availability and to understand glacier evolution under different climatic scenarios in the HindukushKarakoram-Himalayan(HKH) region.This also holds true for the Bhaga basin of the western Himalaya.This study investigates glacier and glacier lake changes in the Bhaga basin,over the last five decades ...     

Cover Story

The photo on the cover is of the upper reaches of the Aktru River basin located in the south-eastern part of the Altai Republic of the Russian Federation close to the borders to Mongolia and China in the centre of the Eurasian Continent (50°06’03"N,87°40’14"E).The peak in the background is called’Black Mountain’(Karatash in Russian) and reaches an altitude of 3,534 m.a.s.l.This mountain separates the Maliy AktrLI glacier to the left and Bolshoy glaciers to the right.The Maliy glacier has experienced extremely rapid rates of glacier retreat since measurements began in the 1950s.     

The Maximum Ice Age Glaciation between the Karakorum Main Ridge （K2） and the Tarim Basin and its Influence on Global Energy Balance

A modern research approach and working techniques in hitherto unexamined areas, produced the following results: 1). The tongues of decakilometre long Karakorum glaciers belong to temperate ice-streams with an annual meltwateroutput. The short Aghil glaciers on the contrary are continental, arid and cold. 2). The present-day oscillations of the Karakorum glaciers are related to their own mass, and are contrary to and independent of the actual climate. Only the short glaciers, with steep tongue fronts, show a present-day positive balance. 3). ^14C- dated Late Glacial moraines indicate a 400-800 m thick valley glacier at the former confluence point of the K2-, Sarpo Laggo- and Skamri glaciers. 4). From the evidence of transfluence passes with roches moutonn6es, striae and the limits of glacial polishing, as well as moraines and erratics, a High Glacial at least 12oo m thick ice-stream network between the Karakorums and the Kuen Lun north slopes was reconstructed. The Shaksgam and Yarkand valleys were occupied by glaciers coming from west Tibet. The lowest-lying moraines are to be found in the foreland down to 2000 m, indicating a depression of the High Glacial (LGM) snowline (ELA) by 13oo m.5). The approximately 10,000 measurements of the radiation balance at up to heights of 5500 m on K2 indicate that with incoming energy near the solar constant the reflection from snow- covered ice is up to 70% greater than from rock and rock waste surfaces.6).These results confirm for the very dry western margins of Tibet an almost complete ice sheet cover in an area with subtropical energy balance, conforming with the Ice Age hypothesis of the author which is based upon the presence of a 2.4 million km^2 Tibetan inland ice sheet. This inland ice developed for the first time when Tibet was uplifted over the snowline during the early Pleistocene. As the measured subtropical radiation balance shows, it was able to trigger the Quaternary Ice Ages.     

Evolution and bathymetry of glacial lake at the lowest elevation in Nepal Himalaya

One of the prominent impacts of climate change induced glacier retreat in the Himalayas is the formation and expansion of glacial lakes. The newly formed glacial lakes are mostly located in higher altitudinal regions(4200-5800 m) of Himalaya,however, a new glacial lake(Kapuche, 28.446° N and 84.116° E) have been reported to be emerged in the relatively low elevation area of ～2450 m above sea level(masl) in the Nepal Himalaya. This short communication presents the remote sensing-based evolution a...     

Glacier extent changes and possible causes in the Hala Lake Basin of Qinghai-Tibet Plateau

Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends. Glacier changes are also of great significance to the regulation of regional water resources. This study selected the Hala Lake Basin in the northeastern Qinhai-Tibet Plateau as a study area, and examined the relationships between the temporal and spatial change of glaciers in the northeastern Qinghai-Tibet Plateau and climate change based on remote sensing imagery,climatological data, and topographic data during the past 30 years. Results showed that glacier area in the Hala Lake basin fluctuated and decreased from106.24 km~2 in 1986 to 78.84 km~2 in 2015, with a decreasing rate of 0.94 km~2·yr~(-1). The number of glacier patches, mean patch area, and largest patch index all decreased from 1986 to 2015, while the splitting index increased from 1986 to 2015,indicating that the landscape fragmentation of glacier in the Hala Lake Basin was increasing significantly during the study period. Glacier area change was mainly concentrated in the slopes 25° with an altitude of 4500-5000 m, and the retreating rate of glacier of sunny slope was obviously higher than that of shady slope. Geometric center of glacier in the basin moved from southwest to northeast towards high altitude. Results of the response of glacier extent to climate change showed that temperature was the dominant factor affecting glacier area dynamic change in the Hala Lake Basin. It is predicted that in future several years, the glacier area will decrease and fragment continually as a result of global warming on the Tibetan Plateau.     

Reconstruction of the Ice Age glaciation in the southern slopes of Mt. Everest, Cho Oyu, Lhotse and Makalu (Himalaya) (Part 1)

In the Khumbu-and Khumbakarna Himalaya an ice stream network and valley glacier system has been reconstructed for the last glacial period (Würmian, Last Ice Age, Isotope stage 4–2, 60–18 Ka BP, Stage 0) with glaciogeomorphological and sedimentological methods. It was a part of the glacier system of the Himalaya and has communicated across transfluence passes with the neighbouring ice stream networks toward the W and E. The ice stream network has also received inflow from the N, from a Tibetan ice stream network, by the Kyetrak-Nangpa-Bote Koshi Drangka (Valley) in the W, by the W-Rongbuk glacier valley into the Ngozumpa Drangka (Valley), by the Central Rongbuk glacier valley into the Khumbu Drangka (Valley) and by the antecedent Arun Nadi transverse-valley in the E of the investigation area. The ice thickness of the valley glacier sections, the surface of which was situated above the snow-line, amounted to 1000–1450 m. The most extended parent valley glaciers have been measured approx. 70 km in length (Dudh Koshi glacier), 67 km (Barun-Arun glacier) and 80 km (Arun glacier). The tongue end of the Arun glacier has flowed down to c. 500 m and that of the Dudh Koshi glacier to c. 900 m asl. At heights of the catchment areas of 8481 (or 8475) m (Makalu), i.e., 8848 (or 8872) m (Mt. Everest, Sagarmatha, Chogolungma) this is a vertical distance of the Ice Age glaciation of c. 8000 m. The steep faces towering up to 2000 m above the névé areas of the 6000–7000 m-high surfaces of the ice stream network were located 2000–5000 m above the ELA. Accordingly, their temperatures were so low, that their rock surfaces were free of flank ice and ice balconies. From the maximum past glacier extension up to the current glacier margins, 13 (altogether 14) glacier stages have been differentiated and in part 14C-dated. They were four glacier stages of the late glacial period, three of the neoglacial period and six of the historical period. By means of 130 medium-sized valley glaciers the corresponding ELA-depressions have been calculated in comparison with the current courses of the orographic snow-line. The number of the glacier stages since the maximum glaciation approx. agrees with that e.g. in the Alps and the Rocky Mountains since the last glacial period. Accordingly, it is interpreted as an indication of the Würmian age (last glacial period) of the lowest ice margin positions. The current climatic, average glacier snow-line in the research area runs about 5500 m asl. The snow-line depression (ELA) of the last glacial period (Würm) calculated by four methods has run about 3870 m asl, so that an ELA-depression of c. 1630 m has been determined. This corresponds to a lowering of the annual temperature by c. 8, i.e., 10°C according to the specific humid conditions at that time.     

Current Vegetation Pattern along Glacial Landscape in Central （Garhwal） Himalaya, India

Introduction High mountain ecosystems are comparatively thrilling and sensitive at least at the upper elevation levels, and are determined by abiotic climate related ecological factors. Therefore, the ecosystems at the low temperature limits of plant life are generally considered to be particularly sensitive to climate changes (Koerner 1999). As temperature is a key factor for high mountain plants (Koerner and Larcher 1988, Gottfried et al. 1998), an upward migration of species must be conse…     

Hypsometric properties of mountain landscape of Hunza River Basin of the Karakoram Himalaya

Within Karakoram Himalaya, Hunza River Basin(study area) is unique for a number of reasons: 1) potential impacts of highly concentrated highpitched mountains and glacial ice; 2) the glaciated portions have higher mean altitude as compared to other glaciated landscapes in the Karakoram; 3) this basin occupies varieties of both clean and debriscovered glaciers and/or ice. Therefore, it is imperative to understand the stability of topographic surface and potential implications of fluctuating glacial-ice causing variations in the movement of material from higher to lower elevations. This paper advocates landscape-level hypsometric investigations of glaciated landscape lies between 2280–7850 m elevation above sea level and non-glaciated landscape between 1461–7570 m. An attempt is made to understand intermediate elevations, which disguise the characteristics of glaciated hypsometries that are highly correlated with the Equilibrium Line Altitude(ELA). However, due to data scarcity for high altitude regions especially above 5000 m elevation, literature values for climatic conditions are used to create a relationship between hypsometry and variations in climate and ELA. The largest glaciated area(29.22%) between 5047 to 5555 m lies in the vertical regime of direct snow-accumulation zone and in the horizontal regime of net-accumulation zone(low velocity, net freezing, and no-sliding). In both landscapes, the hypsometric curves are ‘slow beginning' followed by ‘steep progress' and finally reaching a ‘plateau', reflecting the rapid altitudinal changes and the dominance of fluvial transport resulting in the denudation of land-dwelling and the transport of rock/debris from higher to lower altitudes. Reported slight differences in the average normalized bin altitudes against the cumulative normalized area between glaciated and non-glaciated landscapes are an indicator of slightly different land-forms and landform changes.     

MASS BALANCE SENSITIVITY TO CLIMATE CHANGE: A CASE STUDY OF GLACIER NO. 1 AT URUMQI RIVERHEAD, TIANSHAN MOUNTAINS, CHINA

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Significance of glacio-morphological factors in glacier retreat: a case study of part of Chenab basin,Himalaya

A study has been carried out in part of Chenab basin,Himalaya to understand the relationship between glacio-morphological factors and change in glacial area. Initially change in areal extent of glaciers was derived for two time frames(1962-2001/02 and 2001/02-2010/11). The study comprised of 324 glaciers for the monitoring period of 1962-2001/02 for,which 11% loss in glacial area was observed. Two hundred and thirty-eight glaciers were further monitored between 2001/02 and 2010/11. These glaciers showed an area loss of 1.1%. The annual deglaciation has been found to be higher during the period of 1962-2001/02 compared to 2001/02-2010/11. The spatial and temporal variability in deglaciation was also addressed usingglacio-morphic parameters. Area,length,percentage of debris cover,and various elevation parameters of glaciers were observed to have significant controls on relationships to the rate of glacial shrinkage. Largerarea and longer glaciers show a lower percentage of retreat than smaller and shorter ones. Moreover,glaciers located at lower altitudes and having gentle slopes show more area retreat. The results of area retreat in debris covered and debris free glaciers supports that the glaciers covered by debris retard ice melting at some extent. 158 glaciers were observed having no debris cover,and these exhibit 14% of loss in surface area. In glaciers having 40% debris cover,8% of deglaciation was observed. The glaciers located below equilibrium line altitude(ELA) have experienced 4.6% of deglaciation for the time frame 2001/02 – 2010/11 whereas it was found to be 1.1% for the glaciers occurring above ELA. However,theorientation of glaciers did not show any considerable influence on glacial change based on hypothesis.     

New findings concerning the Pleistocene Glaciation of the Leh Basin,Ladakh (34°03′ N/77°38′ E)

Like for most parts of High Asia, researches concerning the Pleistocene landscape evolution of the Leh Basin (34°03′ N/77°38′ E) have also left contradictions. To push this topic, three up to now unexplored Ladakh Range tributaries of the Leh Basin (Stagmo-, Arzu- and Nang-Valley) have been investigated. U-shaped profiles, transfluence passes, moraine mantled and glacially rounded peaks and ridges, roches moutonnées, glacial flank polishings and ground moraines document the former glaciation of the study area. The ice fillings of these tributaries reached a minimum thickness up to 540 m. Even at the valley outlets and on the orographic right side of the Leh Basin, the glaciation was more than 350 m thick. Based on these empirically extracted results, theoretical snow line considerations lead to the conclusion that the whole Leh Basin was filled up by a former Indus-Valley glacier. An ice injection limited to the nourishment areas of the Ladakh Range valleys could not have caused the reconstructed ice cover (down to 3236 m a.s.l.), which is proved by extended ground moraine complexes. Only an Indus ice stream network (most likely during the LGP), nourished by inflowing glaciers of the Ladakh- and Stok Range, explains the widespread existence of the glacial sediments at the outlets of the investigated valleys.     

Glacier variations and rising temperature in the Mt. Kenya since the Last Glacial Maximum

High-resolution imagery can be used to reconstruct former glacier boundaries through the identification of glacial erosional and sedimentary geomorphology. We employed moraine mapping and the accumulation–area ratio method(AAR), in conjunction with Landsat, Google Earth, and SRTM imagery, to reconstruct glacier boundaries and equilibrium-line altitudes(ELAs) for Mt. Kenya in the Last Glacial Maximum(LGM), the Little Ice Age(LIA), and at present. Our results show that the areas of Lewis Glacier and the Tyndall-I glacier system were 0.678 km~2 and 0.390 km~2, respectively, during the maximum of LIA. Those mean that the both glaciers have shrunken by 87.0% and 88.7%, respectively since the LIA. Area change ratios for each glacier were significantly larger in the period of 2000 through 2015 than the former periods, indicating that glacier recession has accelerated. Continuous ice loss in this region has been driven by rising temperature and fluctuating precipitation. Linear regression data for Lewis glacier show that mass balance sensitivity to dry season temperature was –315 mm w.e./℃, whereas the sensitivity to dry season precipitation was 5.2 mm w.e./mm. Our data also show that the ELA on the western slope of Mt. Kenya rose by 716-816 m from the LGM to the modern era, corresponding to that temperature rose by 5.2℃-6.5℃.