25 November 1984, Volume 5 Issue 3
    

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  • Wu Guanghe, Yutaka Ageta, Qiu Jiaqi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 5-16. https://doi.org/10.7522/j.issn.1000-0240.1983.0033
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    Bogda is one of the important component parts of the Chinese Tian Shan, located between 43°10’-45°5’ N and 87°40’-91°35/ E, having a general strike from east to west with its middle section as an arc pointing southward. Tectonically it is an anticlinorium of the late Caledonian or Early Variscian foldbelt of the Tian Shan geosyncline with the property of a fold-block mountain. Difference in tectonic movements of the basins on both sides of the mountains makes the southern and northern slopes obviously asymmetric and terrace-structured. Its highest peak, Mt. Bogda, 5445 metres a. s. 1., is located at the western end of the Bogda mountain range. Its altitude lowers continuously from west to east. In its eastern section, the mountain range is in medium size.There are about 50 rivers in the Bogda area disbursing asymmetrically on both sides of the ridge in dendritic shape. Rivers are all short and their gradient is steep with a total runoff of about 1700 million m3. Some rivers on the southern slope dissect through the ridge and make the divide line move northward, thus decreasing the difference in runoff on two sides. Longitudinal valleys develop in the upper reaches of Kaikeng river, Mulei river and others, widening their drainage basins in the high altitudes with the richest precipitation. Therefore, the biggest river is not located in the vicinity of main peak but in the middle section on the northern slope.Modern vegetation and soil of Bogda mountain range developed in the process of glacial retreat since the end of late Pleistocene. Northern slope of the mountain range shows vertical natural landscape zones as follows: alpine ice and snow, alpine sub-glacial, alpine meadow-steppe, mountain forest, and mountain steppe, taking desert zone as their faundamental zone. Forest zone is absent on the southern slope of the mountain range where desert zone went up to about 1800 metres above sea level and became a part of the vertical zones.The variation of latitudinal zonality in temperature gives the Bogda Area a more favorable low temperature condition necessary for glacial development than other mountains in west China except for the Altay. Therefore. the altitude of glacial distribution in the Bogda is lower than that in all the other mountains. But because of the effects of unusual heat in the Turpan Basin on its southern side and of inversion layer in the Junggar Basin in winter on its northern side, the rate of vertical decrease in temperature is rather small, and the annual average of 0℃ isotherm being uplifted by 800 m. The snowlines are correspondingly higher as well. Therefore the "altitude span" of the high mountain glaciation has been reduced and the scale of glaciation also restricted.The Bogda range is situated in the belt-shaped rainy area of central Xinjiang with a precipitation much more aboundant than that in the dry basin on its both sides and increasing with altitude. The maximum rainy belt is situated in the high mountain area above 3500 m.At above 3900 m on the northern slope and 4000 m on the southern slope, the average annual temperature is below -9℃ and the average monthly temperature from June to August is below zero. The annual precipitation is 670 mm, all in solid state. Such combination of heat and moisture in low temperature semi-humid pattern already satisfies glacial development, but far from optimum condition. The Bogda mountains with a strike from east to west and a precipitation source mainly from westerlies and north-westerlies obtain heat and moisture for glacial development favourable on the northern slope, but unfavourable on the southern slope, reflecting greatly the pattern of glaciation on the southern and northern slopes, both in number and in scale and well as in other respects. But in the region of Bogda peak, the relief condition offsets partly this difference.
  • Wang Yinsheng, Qiu Jiaqi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 17-24. https://doi.org/10.7522/j.issn.1000-0240.1983.0034
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    Bogda area is the biggest centre of glaciatiqn in the Eastern Tianshan of China. It has not only more precipitation than other area in the Eastern Tianshan but also the advantage of low temperature, so that it is favourable for glacier formation and existence.The elevation of the snowline is about 3820 m on the northern slope and 3910 m on the southern slope. The annual mean air temperature near the snowline on the northern slope is estimated at about -10.0℃ or so. The 0℃ isotherm of mean annual temperature coincides approximately with the 2550 contour on the northern slope and 2800 m on the southern slope. The annual precipitation above the snowline on the northern slope exceeds 600 mm.The glacier distribution is more concentrated in Bogda area than other parts of the Eastern Tianshan with a total area of 101.42 km2 and a coverage of 24.5%. There ate 112 glaciers in the investigated area, 53 on the northern slope and 59 on the southern slope. The size of the glaciers in this area is not very big and glaciers with an area over 10.0 km2 and below 1.0 km2 are respectively 2% and 78% of the total glacier area.The hanging glacier prevails in a great number, but its total area is rather small. However, cirque-valley and valley glaciers here are prevailing in area. The height difference of glacier action is over 2000 m and the glacier coefficient is about 1.0, maximum 1.3 and minimum 0.6. The above mentioned features of glacier types and sizes are relevant to their continental climatic conditions, retreat of glacier and geographic position.
  • Okitsugu Watanabe, Yutaka Ageta, Ren Jiawen
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 36-36,35. https://doi.org/10.7522/j.issn.1000-0240.1983.0035
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    Firn stratigraphic studies of glaciers in the eastern Tian Shan were carried out during the summer of 1981.This is a preliminary study for the clarification of long term climatic change by means of analyses of snow-ice cores obtained from the glaciers. Firn cores to the depth of 2-6 meters from the surface were obtained by means of a hand auger on Glacier D-4 on the north slope of Mt. Bogda and the west part of Glacier No. 1 in the area of Urumqi river head waters.Stratigraphic descriptions, measurements of physical properties and analysis of oxygen isotopic contents were made. Using those data, stratigraphic interpretation of an assessment of annual layers and the process of superimposed ice formation are attempted. As annual net balances at the several sites of Glacier D-4, various amounts of around 1,000mm are found. This is an unexpected value in comparison with the value of precipitation obtained previously in the vicinity of the glacier.Mass balance measurements by the stake method were made on Glacier D-4. A linear relation between mass balance and altitude on the glacier in the warmest season is found.
  • Xie Zichu, Wu Guanghe, Wang Zhongxiang, Zhang Wenjing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 37-46. https://doi.org/10.7522/j.issn.1000-0240.1983.0036
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    This article tries to give a description of the peculiarity of the ice formation of the glaciers on the northern slope of Bogda, its unique belt pattern structure and the reflection of climatic changes on ice formation process in the last twenty years.In the area investigated, the temperature is low and the precipitation high, providing cold storage and material sources favourable for ice formation. At the same time, the existence of paleo-peneplain at about 4000 m a. s. 1., close to the snow line of the modern little ice age, is advantageous for the formation of mature cirques or firn basins on it.Because the glaciers are comparatively stable at present, the firn line and the zero-equilibrium line are more suited to the landforms. The surface slope of the glacier at its height is very small, therefore infiltration-congelation belt widely develops with its width far more wider than all other glaciers in the source area of the Urumqi river. The infiltration-congelation belts grow on the gentle passes at about 4100 m a. s. 1., forming inversion phenomemon of ice formation belt.In the past it is believed that the thickness of the firn layer of the infiltration belt in the eastern Tian Shan is less than 5 m. According to data from drilling, the authors found that it may reach 10 m thick, i. e., close to the bottom of active layer. This shows that on the profile of the firn layer there must be many annual layers and that the time of ice formation lasts also much longer than 2-4 years as estimated in the past.Frequent avalanche and avalanche cone and accumulation of snow drift in Bogda Mts. arc important supply source for the glaciers. Melt water from the surface of the avalanche cone can make the temperature of the firn in the active layer reach 0℃ in summer, shewing a thermal infiltration in ice formation. Temperature turns back to negative in the winter and a cold infiltration ice formation appears again. In view of the above, the authors suggest a conception of the ice formation in the form of an avalanche cone.
  • Yutaka Ageta, Qiu Jiaqi, Tetsuzo Yasunari
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 47-58. https://doi.org/10.7522/j.issn.1000-0240.1983.0037
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    On glaciers in the eastern Tianshan Mountains, separate measurements of amounts of accumulation and abation are difficult, since accumulation and ablation occur simultaneously in the warm season. To estimate accumulation and ablation independently, meteorological observations around Glacier D-5 were made in summer. In comparison with air temperature on the ground, much lowering of that and smaller diurnal range were seen on the glacier. From the analysis of upper weather charts, the main cause of precipitation is attributed to the cold trough from the polar region. Since the relation between the probability of occurrence of solid precipitation (S:%) and surface air temperature (T: C) is important for glacier accumulation, the relation of [S=-25T-108 ] is obtained from the observational results. The relation between ablation (a : cm water) and the degree day index (∑T: sum of daily mean air temperature. (.day) is also obtained as [a = 1.5∑T]. By the use of these relations, accumulation, ablation and balance on the glacier are estimated. The agreement between the calculated balance and observational results is fairly good except when the glacier is covered by new snow with high albedo Meteorological conditions and mass balance arc compared briefly with those in the Nepal Himalaya.
  • Zhang Wenjing, Xie Zichu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 59-70. https://doi.org/10.7522/j.issn.1000-0240.1983.0038
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    Solid precipitation in existing glacial area on northern slope of Bogda is absolutely dominant. About 77 percent of the annual precipitation is concentrated in months May-September, commensurable to the total accumulation amount. From the record of Tianchi from 1980 to 1981, precipitation in the glacier area is found to be more than 600 mm. Because of differences in solar radiation with slope facing, the source of water vapour and other factors, glacial accumulation is distinctly different according to slope facing. Data from snow pits do not perfectly show the regularity of the increase in net accumutation with the rise of elevation. The net accumulation amount (water equivalent) of glacier No.4 was 4.36×105 m3 during 1980-1981, and the mean depth of net accumulation (water equilalent) was 147.3 mm.According to mean annual temperature data for many years the period of glacial ablation in this region is from May to September, and the strongest from June to August, during which glacial ablation is closely correlated with temperature and elevation. Because a large part of precipitation is concentrated in ablation period and new snow has a stronger reflection rate, the strength of net ablation is influenced to a certain extent. During serveying, the net ablation amount (water equivalent) of Glacier No.4 was 4.127×105 m3 and the mean depth of net ablation is 139 mm, the net ablation gradient being 1.35 mm/m.The mass balance of glacier No.4 was negative during 1980-1981. The level of the mass balance was not high (only 600 mm). It is consistent with Laohuogou glacier, in Qi Lian Shan (641 mm) and with glacier No.l at the head of Urumqi river, Tian Shan (685 mm), but much less than Guxiang glacier, Pomi county Tibet (2678 mm).
  • Okitsugu Watanabe, Yutaka Ageta, Zhang Wenjing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 82-82,81. https://doi.org/10.7522/j.issn.1000-0240.1983.0039
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    Preliminary structural glaciological studies of the glaciers on the north slope, of Mt. Bogda were carried out during July-August, 1981.The distributions of structural elements, such as depositional and dynamical structures and also structures resulting from glacier fluctuations, were observed on the surface of Glaciers D-4 and D-5 and structural maps of both of glaciers were made.In contrast to the structure of Glacier D-4. which is simple and monotonous. that of Glacier D-5 is more complicated. Clarification of the inner structure of Glacier D-5 is attempted.The surface ice movement and the occurrence of the debris laden layer were observed on both glaciers. Surface deformation and the change of terminus position were measured on Glacier D-5. Mean daily velocities are on the order of several cm per day and the glacier terminus retreated about 1 to 3 meters per month in late summer. 1981 .
  • Ren Jiawen
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 83-89. https://doi.org/10.7522/j.issn.1000-0240.1983.0040
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    Although the glaciers in Bogda area of Tian Shan were investigated in past years, the ice temperature observation was carried out only for the first time.During the joint expedition to Bogda area by Chinese and Japanese glaciologists, a 20 m deep hole was bored with steam drill at some 3750 m a. s. 1. in the upper ablation area of the Bogda Fan-shaped Diffluence Glacier on July 29, 1981.Seventeen thermal resistor thermometers were put into the hole at intervals of 1-2 m, and four observations were taken respectively on 8, 11, 13 and 15 August.Analysis of the records shows that there was a zero temperature layer of liquid water at least 0.5 m deep on the glacier surface in summer. The ice temperature dropped with the increase in depth, and the lowest, being about -3℃, located in the layer 4-7 m deep. Below this layer, temperature went up in a vertical gradient γ=0.148℃/m, and reached the pressure melting point at about 26 m deep. Besides, it was calculated that the equilibrium temperature at the lower limit of the active layer at the equilibrium line of the glacier T0 (16)E equals to -3.4℃. Thus, there might be temperate ice in the lower layer of the glacier. The ice temperature of Bogda Fan-shaped Diffluence Glacier may be higher than other glaciers in Northwest China. Further observation of this glacier may provide new informations for the classification of the continental type glaciers in China.
  • Okitsugu Watanabe, Nobuko Kanamori, Yutaka Ageta, Wu Xiaoling
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 91-100. https://doi.org/10.7522/j.issn.1000-0240.1983.0041
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    The stundy on chemical composition of glaciers is important to know the characteristics of the material circulation in the atmosphere, hydrosphere, lithosphere and the interaction between these sphere.Ninety samples of precipitation, snow, ice and melt water for chemical analysis were collected during the summer in 1981. These samples were brought to the laboratory in Nagoya University for the determination of F-, Cl-. SO42-, NO3- and K+, Na+, Ca2+, Mg2+. Samples arc classified into 5 groups, namely-New snow, snow cover, glacier ice, dirt band and surface melt water, The mean concentration and standard deviation of various chemical components in each group of samples are estimated. General tendency of the concemration among these groups are described. The concentration of each anion and cation in dirt band has 2-7 times higher value than it in other groups.
  • Okitsugu Watanabe, Wu Xiaoling, Koichi Ikegami, Yutaka, Ageta
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 101-112. https://doi.org/10.7522/j.issn.1000-0240.1983.0042
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    For the study of glacier nourishment and the hydrological characteristics in inland Asia, measurements of oxygen Isotope composition were carried out on samples of precipitation and glacial water collected during the period from the middle of July to the middle of August in 1981. δ18O values of each half day precipitation at Tian Shan Meteorological Station (13°06’N, 86°50’E; 3539m) and the base camp (3640m) in the Mt. Bogda region during the observed period had a weighted average of -10~-11‰ with a range between -1‰, and -16‰). The daily mean δ18O value of precipitation decreased with a decrease in daily mean air temperature. δ18O values of glacier ice and snow were less than those of summer precipitation. The difference of δ18O values between the precipitation and the glacial water is attributed to the dependence of the oxygen isotope composition on the air temperature.
  • Kang Ersi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 113-122. https://doi.org/10.7522/j.issn.1000-0240.1983.0043
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    On the high mountain zone of the north flank of Mt. Bogda, the conditions of precipitation, topography and air temperature above the firn line are advantageous to glacial formation, and below the firn line, on the other hand, the tongues are provided with the favorable conditions for ablation, thus, the glaciers are rather capable of producing meltwater runoff. The glaciers, although developing on a small scale, still play an important role in the runoff formation in the mountainous region, for Tianshan Mountains become lower and smaller here, and the runoff produced from the mountains decreases correspondingly.Although the daily course of meltwater runoff on the glacial surface coincides basically with that of air temperature, because of the influence of the changeable weather in this region during ablation season, it displays different features every day. There are many glacial lakes, which play a certain role in the runoff regulation, reducing the runoff fluctuation. There is a relatively close relationship of positive multiple linear correlation between daily runoff depth of glacial meltwater, air temperature and wind velocity, but the closest correlation is still between the runoff depth and air temperature. The discharge hydrography and the runoff volume of glacial meltwater can be estimated in this region by means of air temperature data and glacial ablation area, the obtained formula is as follows; Q=F(0.03T+0.14) where F is the glacial ablation area (km2); T is the daily mean air temperature (℃) at Tianshan Meteorological Station during June, July and August, when the glacial ablation occurs predominately; Q is the daily discharge (m3/s) of meltwater runoff over the area F. A reasonable result has been obtained by using this formula.The glacial meltwater runoff is a main feeding source of rivers originating from the mountains, and plays a role of runoff regulation from year to year. The catchment area of the Baiyang River on the flank is only 9.7% glacier covered, but the contribution of glacial meltwater runoff to the river flow accounts annually even for 37.6%. The total runoff volume of glacial meltwater in eastern Tianshan is annually estimated at about 3.88×108m3.
  • Zheng Benxing, Wang Cunnian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 123-132. https://doi.org/10.7522/j.issn.1000-0240.1983.0044
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    Abundant traces of ancient glaciation exist in the periphery of the contemporary glaciers in the region of Mt. Bogda. At the upper reaches of the rivers, there are double U-shaped valleys, cirques and a lot of end moraines in the lower U-shaped valley. At the lower reaches of Sangong river and Sigong river on the northern slope, there are low glaciofluvial terraces, middle and high morainic terraces, outwash fans near the outlets and alluvial-puvial plains outside the outlets. It has been shown by our field investigation, analyses of grain size, rock and clay mineral, C14 date, and spore-pollen that, during Quaternary, at least three glaciations and one Neoglaciation in Holocene took place in this region, that is, the high moraine platform of Tiantai Glaciation, the middle moraine terrace of Tianshan Glaciation, the Linchang (Forest Station) end moraine and Luweibaliang moraine of Tianchi Glaciation, as well as the Xiaohaizi end moraine of Tianfeng Neoglaciation in Holocene.During the Early Pleistocene, the climate became cold for many times, there may be small glacier, but no glacial deposit, only cemented conglomerate in river facies at the pediment zone had been found. In the Tiantai Glaciation of Middle Pleistocene, the wide-tail valley glaciers 30 km long developed on the northern slope, and the valley glaciers of more than 10 km long on the southern slope. Because of the strong uplifting of the mountains at the end of Middle Pleistocene, the mountain body enlarged and river valleys deepened, the original pediment moraine was uplifted to the altitude of 1100-1300 m, as high as the top of the present lower mountains. In Late Pleistocene, quite large and long valley glaciers developed, the termini of which moved at least down to 1200 m a. s. 1. on the northern slope, even reaching the vicinity of outlets. In the Last Glaciation, which can be divided into two subglaciations, the glaciers moved to the middle mountain zone. In Neoglaciation of Holocene, small valley glaciers several kilometres long developed, with their termini at: 3200-3400 m a. s. 1..
  • Zheng Benxing, Zhang Zhenshuan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 133-142. https://doi.org/10.7522/j.issn.1000-0240.1983.0045
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    It was found from our field work of 1981 in Bogda area that the moraines of Neoglaciation in Holocene are of small scale, 1-5 km away from the existing glacial termini. These moraines occupy only a little more than a half of the lower U-shaped valley and their tills have been weakly weath- ered with no caliche on their surfaces, obviously different from the tills with caliche formed under the dry and hot climate during the climatic optimum in Holocene. The C14 age of the caliche at the head of Urumqi river is 5500?220 B.P. and 3949?141 B.P.. Therefore, the earliest glacial advance of Neoglaciation may be considered as 3000 years ago corresponding to the age 2980 ?150 ago of the first glacial advance in the Neoglaciation of Qinhai-Xizang Pltaeau.The end moraines of the three stages of glacial advance in Neoglaciation are very distinct in this region, for example, the end moraine at the altitudes of 3200 m, 3500 m and 3600 m in front of the Glacier No.5 in the Sigong river head on the northern slope of Mt. Bogda; the series of end moraine at the altitutes of 3320 m, 3420 m and 3540 m in front of the Glacier No. 10 at the Cuban Bogda river head on the southern slope of Mt. Bogda; and the end moraine at the altitudes of 3560 m, 3600 m and 3640 m in front of Glacier No.l, as well as at the altitudes of 3580 m,3640 m and 3720 m in front of Glacier No.6 at the Urumqi river head.The three stages of Neoglaciation reflect the strong climatic fluctuation in a period of every 1000 years, that is, at about 3000 years ago, 2000 years ago and 300 years ago.The end moraine of the Little Ice Age from 300 years ago up to now can be divided into 4 rows reflecting a period of variation at every 100 years, formed in 17th, the middle of 19th century, the beginning of 20th century to the 1930s, and the 1960s respectively. The eight rows of end moraine in front of glacial tongue moraine lakes at No.10 Glacier of the Guban Bogda river, probably reflect a periodic climatic variation of about every 30 years.
  • Wu Guanghe, Zhang Shunying, Wang Zhongxiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 143-152. https://doi.org/10.7522/j.issn.1000-0240.1983.0046
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    On the basis of the standard tree ring sequence, it is pointed out that there were three stages of modern glaciation in Bogda area and the strongest falls on the second. The three modern end-moraines generally existing at the glacial termini were the products of the second and the third stages in the early 18th century, the middle of 19th century and the 1930s respectively.In the first half of this century, the climate turned warmer again. But a wet period lasting 35 years since 1905 made modern glaciers begin their third great retreat as late as in the 1930s. In the 50 years since 1930, glaciers have retreated continuously but slowly with a velocity generally less than 6 m each year. In the ten years from the end of 1950s to the end of 1960s, glaciers retreated with a quickest rate in the past 50 years, and the variations at the glacial termini were most obvious. But at the sametime, some glacial termini in Bogda remained unchanged for a long period.
  • Kang Xingcheng, Zhang Zhenshuan, Zheng Benxing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 153-157. https://doi.org/10.7522/j.issn.1000-0240.1983.0047
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    This paper discussed the relation of climatic elements to the tree ring using the tree ring data for 147 years in the Bogda area, Tian Shan. After analysis of the climatic variations in the last 150 years, the authors found that there were three dry and wet periods i.e. the three wets in 1841-1854, 1869-1877, 1905-1941 and the three drys in 1855-1868, 1878-1904 and 1942-up to present. Further detailed analysis reveals that the climate tended to be drier and drier in the past 150 years and reached the climax in 70 s and turns to wet in early 80 s. Moreover, the duration of dry spells is becoming longer and longer (the first dry spell lasted 13 years, the second 24 years and the third 34 years) . The wettest period happened in the first half of this century, and the driest in the 70 s.Because this result agrees fundamently with that of the surrounding regions, we deduce that since the little ice age, there might be four dry and wet spells of climatic variations in this region. The earliest one might happen near the end of 17th century up to beginning of 18th century.
  • Okitsugu Watanabe, Yutaka Ageta, Shuji Iwata
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 159-170. https://doi.org/10.7522/j.issn.1000-0240.1983.0048
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    Glacier No. 3 is a cirque type-compound glacier with a steep accumulation-ablation slope and a typical glacier in the area of the Urumqi river headwaters.Some observations on structural characteristics in the snout area, occurrence and nature of end-and supra-glacial moraine. the mass balance during a certain period and topography of terminal moraine formed during the neoglaciation period were carried out during the summer of 1981. adetailed topo graphtc map of the snout area and terminal moraine is obtained and detailed structure of the dirt band, in which debris is contained, is examined.Oxygen isotopic content and chemical composition of glacier ice including the dirt layer are analyzed. Based on these results, the dirt band can be presumed to be a kind of shear plane and the debris included is sub-glacial till by entrained the pressure melting-refreezing process.
  • Zheng Benxing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 171-178. https://doi.org/10.7522/j.issn.1000-0240.1983.0049
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    Fifty six rows of fluted moraine in the same direction of ice flows and in alternative ridges and gullies on a flat front 370 m wide at the terminus of Glacier No.5 on the northern slope of Mt. Bogda were surveyed in 1981. They are generally 10-40 m long, 1-3 m wide and 0.5-1 m high, the greatest being 110 m long, 12 m wide and 4 m high. Such a group of fluted moraine was recorded in China for the first time, and is moderate in scale as compared with those in North Europe and North America.The composition of grain size in the fluted moraine is similar to that in the end till and basal till,but its content of silt is relatively high, reaching 16.65% ,nearing 18.04% in the lower lodgement till,and higher than 7.7% and 3.6% in the upper lodgement in the eskers. The abrasion exponent in the fluted moraine is 0.63, close to 0.66 in the lower lodgement till, but larger than 0.44 in modern terminal moraine and 0.29 in esker, showing that both the fluted moraine and the lodgement till were rather strongly abrased by glaciers.The fabric of the fluted moraine shows the following characteristics. The dip of long axis A is in the same direction of glacial movement, but on the both sides the farther the down slope, the larger the angle between the dip and the direction of glacial movement, and the dip angle varies from about 10? near the top to 40-56? near the bottom. The dip of maximum AB plane is mostly perpendicular to the direction of ice flow, and the dip angle is rather big, about 2/5 of the gravels is more than 50?.There are big boulders at the head of some fluted moraines, and at the head of many moderate and small rows of the fluted moraines are ice anticlines rich in debris dipping upwards. From above mentioned, the formation of the fluted moraine could be inferred as follows: when the glaciers moved forward,the boulder in the lodgement till distributed unevenly,and hindered the movement of the ice, as a result, a low pressure area in the ice flow occurred in front of the obstacles and forced the lodgement till protrude upward in the form of ridges, and the ice layer folded.
  • Deng Yangxing, Deng Xiaofeng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 179-190. https://doi.org/10.7522/j.issn.1000-0240.1983.0050
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    The physical geographical environment, i.e. steep slope, weathered rock, favourable climate condition etc. particular to the Bogda region, promotes the intensive development of a variety of periglacial action and landforms and of its sediments. According to the action of main exogenetic agent, the periglacial landforms of the region can be divided as follows:1) Frost weathering-gravity action: tor, rock field, block slope, etc,2) Frost creeping action: solifluction terrace, stone stream, scree type rock glacier, rock flow tongue, cryoplanation terrace.3) Nivation-gravity action: nivation hollow-scree cone, avalanche chute and cone, etc.4) Thermothawing action; thaw slide mass and others.5) Frost heaving action: large and small-sorted circle, large and small-sorted stripe,frost heaved block, polygon, small non-sortednet, pingo, etc.Among the periglacial landforms mentioned above the rock field, scree type rock glacier, cryoplanation terrace, avalanche cone, large-sorted circle are extensively distributed and particular to the region.The periglacial action and its derivatives as well as the Bogda region itself are differentiated clearly in vertical zones within a short distance. Generally the zone of frost weathering and nivation-gravity actions mainly developes above 3800 m a.s.l. and the zone of thermo-thawing and fluvial action below 3500 m a.s.l. Between the above two, there is a zone of frost heaving and of thermo-thawing action, a region with strongest periglacial actions and most numerous varieties of periglacial landforms in Bogda area.
  • Zhang Zhenshuan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 191-200. https://doi.org/10.7522/j.issn.1000-0240.1983.0051
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    This pape: discusses the relation between the grain-size characteristics of moraine in the region of Mt. Bogda and its environment by analysing the data of different till grain-size with statistical method. From conventional statistical parameters, the till can be divided into two transportation zones: superglacial and englacial transportation zone and subglacial transportation zone. In the former, the debris retains the original features of collapsecrush, the grain-size distribution follows the Rosin-Rammler Law, i.e. the gravel content is high in percentage, generally 77.7-80.1%, sand 27.5-18.5%, silt 1.4-3.45%, and the clay content is very low, almost none. In the latter, because of the strong abrasion between the glacier and the rock bed, the grain-size distribution of tills deviates from the Rosin Rammler Law and tends to the normal distribution, i.e. the gravel content is generally 44.87-58.2%, sand 23.19-26.61%, silt 12.18-13.15% and clay 5.6ll.87%, and the silt and clay content is much higher than that in the former zone. The peak value of silt content in the tills of subglacial transportation zone can be mainly explained by the glacial abrasion. In order to distingush the glacial sediment environment and to classify till more conveniently, two parameters, matrix index and abrasion index, are used in this paper. They reflect the intensity of glacial crush and abrasion affecting the matrix and debris grain-size in the tillls. In the tills of glaciers of continental type,the matrix index is 0.5-0.96, and the abrasion index is 0.44-0.63. There is a direct proportional relation between matrix index and abrasion index.These two grain-size parameters and their figures of double variables are effective to distinguish the sediment of glacial environment, and worthy for application in the researches on glacial sedimentology.
  • Minoru Yoshida, Okitsugu Watanabe
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 201-208. https://doi.org/10.7522/j.issn.1000-0240.1983.0052
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    No. 3 Glacier has 4 main shear planes in its lower ablation area, which are accompanied by debris-laden ice 5-40 cm thick. Englacial till was sampled from each area of debris-laden ice to examine its characteristics and genesis.Boulder shapes of englacial till are extremely angular and the amount of silt and clay is lower than that of till produced by the abrasion process in. temperate glaciers. Quartz-grain surface features examined by Scanning Electron Microscope showed that Ⅰ) All grains have typical GLACIAL features.Ⅱ) 5-20%of grains show silica precipitation-solution features superimposed on ‘GLACIAL’ features.Ⅲ) Signs of subaqueous mechanical action, impact pits and rounding of edges, are rarely observed.Ⅰ) means that grains were produced by mechanical grinding or crushing. Ⅱ) and Ⅲ) mean that some of the grains were lodged in water after being crushed. but grains were not transported in turbulent water flow.These results suggest that the englacial till was mainly produced by crushing and/or plucking at the base of No. 3 glacier rather than abrasion. At the base of this glacier where the englacial till was entrained, the temperature is kept or has been kept at melting point but the amount of water is less than that of temperate glaciers.
  • Tang Yongyi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 209-216. https://doi.org/10.7522/j.issn.1000-0240.1983.0053
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    Based on the polarization microscopic analysis of moraine in grain size 0.25-0.01 mm in Bogda Region, the characteristics of its fine-grained fragment component may be summed up as follows:1. General characteristics (1) Complexity of moraine component. It consists of more than 40 kinds of light minerals, heavy minerals and rock debris, one of the characteristics of glacial deposits in moraines of Himalaya and Tian Shan mountains.(2) Low maturity of moraine minerals. Shown in the high rate of heavy components and unstable heavy minerals, low index of maturity in minerals (<2), weak weathering, poor sorting, low index of roundness (2-3), etc.,another characteristic of glacial deposits.(3) Wavy valley shape of roundness index curve particular to glacial moraine deposits.2. Regularity of regional distribution of fine-grained components.The content of acanthconite on the top of Mt. Bogda is higher than that on the northern and southern slopes. The content of pyroxene and amphibole on the northern and southern slopes is higher than that on the top of Mt. Bogda. The type of mineral groups is simple on the top of Mt. Bogda and on the southern slope, but complex on the northern slope, reflecting mineral distribution as mentioned above shows the closer relationship of the glacial sedimentation to bedrocks in Bogda region than that in other localities.3. Mineral characteristics of moraine in different glacial perieds.(1) In the moraine from ancient to actual, the contents of heavy component and unstable heary mineral change from low to high, and the contents of stable heavy mineral and ZTR value vary from high to low. It .shows that mineral maturity of ancient moraine is higher than the modern moraine. This characteristic may be taken as the basis of glaciation division.(2) The mineral composition of moraine changes from complex type to simple as the moraine turns from ancient to modern. This regularity correspounds to different glaciations and their dimensions, clear evidences of development and decline of glaciers.
  • Deng Xiaofeng, Wang Cunnian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 217-226. https://doi.org/10.7522/j.issn.1000-0240.1983.0054
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    Some characteristic values were calculated and illustrated by using electronic computer for a large number of gravel fabric data from glacial and periglacial deposits in Bogda region. By comparison and analysis, we found that A axis strike of the gravel in meltout till coincides with the inclining direction of the deposit slope, and A axis and AB plane of gravel in fluted till and basal till incline toward the upper reach. It did not agree with what has been suggested by predecessors that A axis of all types of tills is parallel to ice flow direction, This paper further developed the conception of gravel fabric in several kinds of periglacial deposits for their morphologic description.
  • Qiu Jiaqi, Deng Yangxin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 227-234. https://doi.org/10.7522/j.issn.1000-0240.1983.0055
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    Bogda area is famous for avalanche, which spreads widely and frequently with unusually enormous scale in the Eastern Tian Shan. The basins of two glaciers No. 5Y725D5 and 5Y812B10 on the northwestern slope of Bogda were taken as example to study avalanche in its vicinal area. This paper deals with the problems of avalanche in these two basins, including formation conditions, features,etc.The conditions, that the high mountains are dissected intensely by a lot of nivation funnels, denudation hollows, horns and cliffs combined with a higher precipitation than usual in the Eastern Tian Shan, are suitable for snow accumulation and occurrance of snow slide and large scale intensive avalanche. The vertical height of the fall of avalanche may reach 1500 m and the length of path of avalanche as long as 2500 m.Avalanche in these basins is one of the main sources for glacial nourishment and takes part in the geomorphologic processes for surface erosion, denudation, debris transfer and deposition. Some landforms relative to avalanche were produced in these basins.The dangerous period of avalanche covers all the year round and avalanche is frequent in warm season either during or after snowfall.The confined and jumping avalanches are the prevailing types and the unconfined avalanche is few in number.The density of avalanche path, path length and vertical fall of avalanche in these basins are the biggest in the Eastern Tian Shan.Viewed from the angle of dangerous duration of avalanche, the range of avalanche action and avalanche dynamic features, these basins are considered as the most dangerous areas for avalanche in the Tian Shan, China.
  • Deng Yangxing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1983, 5(3): 235-241. https://doi.org/10.7522/j.issn.1000-0240.1983.0056
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    The glacial debris flow developes on high mountains of valley glaciers or in border zones of snow covers. It is fed mainly by loose solid material of actual as well as ancient moraine or scree material of avalanches and its water source comes from the meltwater of glaciers or the water of bursting moraine dammed lakes. The debris flow of this type is called glacial debris flow.The Bogda region is situated in the Bogda anticlinorium of the Tian Shan fold belt. Strong neotectonic movement, frequent earthquake, development of fold and fault, intensive periglacial action, and repeated glaciation and avalanche erosion provide sufficient solid material for the formation of glacial debris flow. The Bogda Mountains rising abruptly with steep slopes covered by hanging glacier and numerous moraines supply favourable landscape for the outburst of glacial debris flow and its movement. Moreover, the abundant annual rainfall, strong accumulation and ablation of glacier, widely developed avalanches with frequent burst and plentiful supply of melt water all meet the needs of sufficient stream and promote the occurrence of glacial debris flow. The main characteristics of glacial debris flow in the Bogda area may be summed up as follows:1) Widely distributed and mainly situated on the sourthern slope of the Mt. Bogda and below the avalanche cone.2) With complete types of glacial debris flow, having both valley and slope types, glacial and avalanche type, structural and turbulent types.3) Intermittent bursting of glacial debris flow with activities alternatively high and low.4) Close correlation between the activities of glacial debris flow and the retreat of glacier.