25 August 1989, Volume 11 Issue 3
    

  • Select all
    |
  • Li Peiji
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 193-202. https://doi.org/10.7522/j.issn.1000-0240.1989.0027
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The paper reviewed a few of the scientific challenges of the investigations on the cli matic changes during the past century, with stress on the volcanic activities, increase of CO2 concentration as well as the El Nino / Southern Oscillation events, and linked it with snow and ice fluctuations.Our climatic system is a highly nonlinear, interactive system created many feedback loops. Such a complex system could have long-period self-fluctuation even if externalinputs are fixed. The climatic pattern is fragile rather than robust and can change very rapidly. Most of dramatic climatic change occurred in a century or two. Numerically small changes in extrinsic control variables are adequate to explain the significant environment responses. The climatic changes which mark the onset or end of a glacial epoch range in temperature of the order of 4-6℃.Observed temperature trendes indicate that the global temperature warmed by 0.4℃ to 0.5℃ in average and by 1.2℃ to 1.5℃ in the high latitudes during the past century. A slow world-wide heating has taken place from around 1880’s to 1940’s followed by 1940-1965 cooling and warming thereafter.The mean sea level rose by about 12 cm in the past century, which has a high correlation with the trend of global surface air temperature and can be accounted for in terms of the thermal expansion of the upper layers of Ocean and a net melting of glaciers.Computer simulations of the climate change induced by increase of the CO2 concentration with mathematical climate models have verified that the global warming was caused by increased atmospheric CO2. The global temperature rise by 0.4℃ to 0.5℃ seems to be reasonable for a 20 to 25 percent increase in atmospheric CO2.Many studies have shown that another major control of the mean temperature in the northern Hemisphere was volcanic dust in the past century. Direct measurement shows a variation in volcanic loadings, with the lowest values in the warm period when volcanic activity was at a minimum and with the highest values just before the temperature began to decrease sharply when volcanic activity be came to be violent.The El Nino-Southern Oscillation is a remarkably coherent global pattern of oceanic and atomspheric anomalies. It is the dominant global climate signal in year-to-year climate variability which involves ocean warming in the eastern equatorial pacific, fluctuations in atomspheric pressure at sea-level in the tropics, monseen rainfall, and extraordinary winter-time circulation over northern Hemisphere ENSO is associated with major dislocations of the rainfall regions in the tropics which bring drought to productive agricultual areas, torrential rains to other arid regions, and unusual wintertime conditions to mid-latitudes.
  • Wang Jiacheng, Guo Dongxing, Huang Yizhi, Zheng Zhonggong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 203-214. https://doi.org/10.7522/j.issn.1000-0240.1989.0028
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In combination with the investigation of engineering geology for Guliang Mine, the investigation and observation on the seasonally thawed layers in the basin of Huola river in the northern Da Hinggan Ling were carried out in the period from 1985 to 1986. It was found that the characteristic of the seasonally thawed layers is controlled by the air temperature and changes with the different ground surface conditions, water content as well as the soil properties. If the soil type is the same, the maximum of the seasonal thaw depth in the uncovered layers is 0.4-0.5 m deeper than that in the layers covered by vegetation and snow. If the soil type is different, the maximum of the seasonal thaw depth in the gravel is the greatest and the maximum of the seasonal thaw depth of the sandy clay with crushed stone, the sandy clay and the peaty clay is 0.65, 0.5 and 0.4 times as deep as that in the gravel respectively. The refreezing speed of the seasonal thaw layer is controlled by the temperature regime of permafrost besides the air temperature. The seasonal thaw layer in the ground with the annually mean ground temperature of -1 degree centigrade is disapearred about two or three months earlier than that in the ground with the annually mean ground temperature from 0 to-0.5 of degree centigrade. The develop of ground ice in the refrozen thaw layers is not as well as on the Qinghai-Xizang (Tibet) Plateau. The texture of frozen ground in the refrozen thaw layers is mainly in the massive, micro-layered and crevice shapes.
  • Guo Dongxin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 215-222. https://doi.org/10.7522/j.issn.1000-0240.1989.0029
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Huola river is located in the north Da Hinggan Ling, and its geographical coordinate ranges from lat. 52°27 ’-53°03 ’ and long. 121°52 ’ -122°04 ’ administratively, this area belongs to Mohe County of Heilongjiang Province.The features of permafrost in the Basin are that from the centre to the margin of the Basin, the thickness of permafrost becomes thinner, from 100-120 m to 10-20 m, and the mean annual ground temperature gets higher, from -2.9℃ to 0.5℃ . Talik occurs on the surrounding mountains only.Geologic structure controls the topography, facies and the distribution of rocks. Because of the differences of development processes, tectonic activity patterns and external agents between the surrounding mountains and the Basin, geologic structure, sendimentary facies, lithology, development degree of fissures and motive regularities of ground water also vary greatly from place to place. These variations play an important part in the formation of permafrost conditions in the Basin.
  • Wang Xiacheng, GEURTS. Marie-Anne
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 223-229. https://doi.org/10.7522/j.issn.1000-0240.1989.0030
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Determination of absolute pollen concentration and pollen accumulation rate provides information concerning the pollen productivity of either fossil or modern plants. These data are important for other micro-paleontological studies. The determination of pollen concentration and pollen accumulation rate is influenced by frost heaving due to ice lensing processes in periglacial environments.Palynological analysis of a frozen core from the southwest Yukon Territory, Canada, indicates that the pollen accumulation rates of spruce can be suppressed or exaggerated by ice lensing. This is due to the distortion of sediment depth and the measurement of sample volume. The volumetric expansion of water upon freezing and the accumulation of exess water results in an increase of sediment depth and sample volume leading to a miscalculation of pollen accurnation rate or pollen concentration.
  • Chen Xiaobai, Qiu Guoqing, Wang Yaqing, Sheng Wenkun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 231-238. https://doi.org/10.7522/j.issn.1000-0240.1989.0032
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Heavy saline soil is widely distributed in the Northwest, Inner Mongolia, North-east and Shandong provience in China. Salt will be crystallized from soil solution and migrated from warm side to cold side or from wet side to dry side during cooling or vaporizing processes respectively. Consquently, salt heave will be. occured while cooling, resulting in the damage of! road, runway, buildings and hydraulic structures. In common case, crystal susceptibility of saline loam in much stronger than that of saline clay. The more the content of Na2SO4 in soil solution, the stronger the crystal susceptibility of saline soil is. Salt heave can not be completely recovered after cooling-warming cycles, especialy in saline loam. There are two temperature ranges iri which the peak salt heave occured. The two ranges are usually from 3 to 6℃ with a probability P of 100% and 0 to -5℃ and from 4 to 7℃ with P of 100% and -1 to -6℃ with P of 50% or -8 to -11℃ with P of 50% for saline loam. This conclusion is useful for preventing structures from salt heave damage.
  • Yuan Xiuhui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 239-248. https://doi.org/10.7522/j.issn.1000-0240.1989.0033
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on a lot of observed data, this paper approaches the effect of some natural factors, such as the thermal conductivity of seasonal thawing and the hysteresis of ground temperature peak on the depth of permafrost table. With the study of the thermal effect of ground surface and the pulsation of air temperature, we have a discussion on microregional features and expected value of the depth of permafrost table, and a semiempirical formula for calculating the depth of permafrost table on Qinghai-Xizang plateau permafrost area is suggested. Since the formula mainly based on the distribution and conduction of ground temperature, it is called "Ground Temperature Method
  • Liu Gengnian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 249-259. https://doi.org/10.7522/j.issn.1000-0240.1989.0034
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    It is a very useful method to study glacial erosional Landforms, by quantitatively analysing the forms, aspects and altituds of the cirques. In Luojishan Mt. area, there were four factors that influenced the forms of the cirques: (i) more maritime climate, because cloudiress, reduces summer ablation; (ii) on northward (poleward) aspects, because lower temperature and solar radiation protect glaciers from ablation; (iii) on eastward aspects, because ablation of east slope is reduced during the moraing; (iv) higher relief, which provide favourable shelter and shade for glaciers.Here, the cross section shape of the trough valleys can be formularized as: Y=a·xb. Calculations show that b changes from 1.306 to 2.000, and a changes from 0.25 to 0.60. In same trough valley, unsymmetry form of the cross section is due to the differential. strenght of glacial erosion and of differential freeze-thaw conditions on both sides of trough valley.It is noticeable that there are four huge grooves found in Qingshuigou trough valley. Their axis always coincides with the ice flow and parallels to the rock bed. Based on the features of the fraction cracks, it is found that there are two groups of cracks which belongs to press-shear fractures and tensile-shear fractures (tension cracks) respectively.
  • Shen Yongping, Jiao Keqin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 269-278. https://doi.org/10.7522/j.issn.1000-0240.1989.0038
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The moraine plateform in Nyalam, Xizarig, about 4000 m a.s.l., is located on the southern slope of the Himalaya. The weathering crusts and soils have developed on the moraine plateform since the interglacial period after the Nyalam (the Nynyxunglha) glaciation of the middle Pleistocene. Three soil-forming processes, indicating the change of natural environment during the uplift of the Himalaya of Quaternary, can be distinguished from the section of paleosols developed since then.From the paleosols profile, the paleosol of the middle Pleistocene is a soil with dark red coloure and the ferric oxide impregnation matrix, and being the ferric oxide nodules in the bottom horizone. The chemical analysis results show that intensity of the soil leaching was very strong in the paleosol, and some elements were concentrated or displaced in the soils, and the phenomena of weathering differenization appeared. The Fe2O3 was intensively concentrated in the soil. The X-ray diffraction patterns of clay fraction from the paleosol indicate the Chlorite-Kaolinite-Hydromica assemblage, and reflect the wet and warm climate, extensive leaching, acidic milieu and high precipitation. Through the grain-size analysis and observation of surface textures of Quartz sand in 0.355-0.50 mm size by microcopy,we found that soil-forming process is very actived to weathering of parent material.The grain-size of sediments became finer upward the section with silt content of 9.8% to 19.0% from unweathering till to the paleosol. The edges of Quartz grains were rounded and solution features on the surfaces.From what described above, the paleosol of the middle Pleistocene has the characteristics of red earth. The Pollen-Spore analysis result shows also that vegetation has the both features of evergreen broad leaf forest and tropical monsoonal rainforest with Enterolobium cyclocarpum and Quercus sp. and so on. The elevation of Nyalam did not excess 1800 m a.s.l. in that time if we consider the annual mean global temperature was 2 -4℃ higher than that at present.The yellow brown soils developed during the interglacial period of the late Pleistocene because of the uplifting of the Himalaya. The vegetation was the needle and broad leaf mixed forest with Pinus sp. and Quercus sp., the elevation might be at 2500-3100 m a.s.l. in Nyalam. The subalpine shrubby meadow soil is the moderm soil-forming process since Holocene.The evolution of soil-forming processes from the red earth to subalpine shrubby meadow soil reflects that the environment change and trend to cold and dry due to the upheave of the Himalaya. Soil-forming processes were adapted to the change of nature system, the old soil would be retreated. In the profiles of modern soil can be found the relic features of old soils, and have the recent features of soils comprising the characteristic of paleosols.
  • Hu Xiaogang, Li Nianjie
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1989, 11(3): 279-286. https://doi.org/10.7522/j.issn.1000-0240.1989.0039
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Like all other natural processes, the melting process of glacier has the properties on stochasticity and irreversibility. The authors suggest that the mean daily discharge process of glacier melting be regarded as the combination of a definite system indicating the air temperature influence and a stochastic system reflecting stochasticity in a time series.A coupled model consisted of a multivariable regression model with temperature as its variable and a sutoregression model is derived. The correlation between the simulated series and observaed series is significant with the degree of condidence a = 0.01. During July and August, the mean simulative error is 20.0%.