Shorelines are widespread and lake deposits and lake geomorphology are welldeveloped on the northern Tibetan Plateau. Through field observations of lacustrine deposits of NamCo-the highest and largest Quaternary lake ...Shorelines are widespread and lake deposits and lake geomorphology are welldeveloped on the northern Tibetan Plateau. Through field observations of lacustrine deposits of NamCo-the highest and largest Quaternary lake in Tibet, the authors found four-step shore terracescomposed of sands and clays with well-developed horizontal bedding and 3-12 m, 15-22 m, 25-30 m and35-45 m higher than the lake surface respectively, lacustrine deposits resting on the bedrocks and60-150 m higher than the lake surface, and up to approx 50 levees composed of oblate lakeshoregravels. Moreover they found lacustrine and lakeshore deposits making up the terraces and levees onthe bottoms of wide dividing valleys connecting Nam Co with the Rencoyuema, Rencogongma and Jiuru Conorthwest of Nam Co (the valley bottoms are 20 m, 90 m and 60 m higher than the above-mentionedthree lakes) and on slopes north of it, i.e. terraces II and III of Nam Co. Thus they confirm thatNam Co and Ring Co-Jiuru Co had connected with each other several times, i.e. formed a unified largelake several times, rather than had been different lakes connected only by river channels. Fromindications such as the distribution of the highest shoreline and lake deposits and geomorphology,the authors conclude that the total area of the old large lakes on the northern Tibetan Plateau is afew times larger than that of the modern lakes and that the last-stage old large lakes formed inthe interglacial interval of the last glaciation.展开更多
The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of co...The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake's surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+-28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.展开更多
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.Glac...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 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·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.展开更多
Robust climate warming has led to significant expansion of lakes in the central Tibetan Plateau. Using remote sensing data, our quantitative analysis indicates that Siling Co, a saline lake in a characteristic endorhe...Robust climate warming has led to significant expansion of lakes in the central Tibetan Plateau. Using remote sensing data, our quantitative analysis indicates that Siling Co, a saline lake in a characteristic endorheic basin in the central region of the Plateau, has expanded more than 600 km2 in area since 1976. Particularly since 1995, the lake has signif- icantly expanded in response to increasing precipitation, decreasing water surface evaporation caused by weaker winds and less solar radiation, and increased glacier meltwater draining to the lake. Glacie^lake interactions are important in governing lake expansion and are also part of a feedback loop that influences the local climate. Worsening climatic conditions （decreased precipitation and increased temperatures） that could have caused the lake to shrink during 1976-1994 were offset by increasing glacier meltwater feeding the lake, which made the lake nearly stable. We demonstrate that this pattern changed during 1995-2009, when glacier meltwater actually decreased but participation runoff increased and evaporation decreased, leading to expansion of the lake. If climatic conditions became suitable for further lake development, which would be indicated by expansion in lake area, glacier meltwater could be saved in a stable reservoir.展开更多
Lake geomorphology and high-level lacustrine deposits since the mid-late Pleistocene are well preserved in lakes of the Qinghai-Tibet Plateau. According to geological surveys of 17 lake districts in different location...Lake geomorphology and high-level lacustrine deposits since the mid-late Pleistocene are well preserved in lakes of the Qinghai-Tibet Plateau. According to geological surveys of 17 lake districts in different locations of the plateau, combined with interpretations of satellite images and topographic maps, the authors studied the timing of formation and scopes of the pan-lake areas of the plateau and their paleoclimate. The latest two high lake levels （overflow surfaces） on the Qinghai-Tibet Plateau in the Quaternary occurred at N40 to 30/35 ka and N65 to 53 ka respectively. In these time intervals, the plateau was covered by huge interconnected pan-lake systems with a total area of -36 km^2 and a total volume of lake water of 〉530 million km^2, which are about 38 times and 659 times larger than those of the modern lakes respectively. Before this pan-lake period in the late Pleistocene, there had been three high lake levels that occurred at N 132-112 ka, 110-95 ka and 91-72/-83-75 ka respectively, suggesting that the late Quaternary climate on the plateau was unstable and changed rapidly. The -40-30 ka high lake level also appeared in the Tengger desert north of the plateau, suggesting that there existed very strong summer monsoons from South Asia then; the variation in solar radiation with a 20,000 precessional period has special importance for the high-altitude Qinghai-Tibet Plateau in the low-latitude zone of the Earth. Around 30 ka, the pan-lakes at the peripheries of the Qinghai-Tibet Plateau drained out suddenly with rapid uplift of the plateau and cooling. In a short time the huge amount of cold lake water emptied into the Indian Ocean and Western Pacific. The draining event of the pan-lakes brought about the environmental changes of rivers and lakes at peripheries of the plateau.展开更多
The mineral rock salts present in the Mahai Salt Lake of the Qaidam basin exhibit high solubilities in water. In addition, the multicomponent underground brine exhibits a high salinity and is easily precipitated. In t...The mineral rock salts present in the Mahai Salt Lake of the Qaidam basin exhibit high solubilities in water. In addition, the multicomponent underground brine exhibits a high salinity and is easily precipitated. In the natural state, brine transport in the brine layer is extremely slow, and the brine is in a relatively stable chemical equilibrium state with the rock salt media. However, during mining, both the seepage and the chemical fields fluctuate significantly, thereby disrupting the equilibrium and leading to variations in the chemical composition and dynamic characteristics of the brine. Therefore, we selected underground brine from the Mahai Salt Lake, collecting a total of 183 brine samples over three stages of mining（i.e., the early stage of underground brine extraction, the initial stage of mining, and the later stage of mining）. Using a range of analytical techniques, the chemical dynamics of the underground brine water and its evolution were systematically studied. We found that evaporation and enrichment were the main mechanisms of underground brine evolution in the Mahai Salt Lake, with cation exchange and mineral dissolution/precipitation being key factors in determining the dynamic characteristics and evolution of the brine.展开更多
Lake Xingcuo is a small closed, hard\|water lake, situated on eastern Tibet Plateau. Stable isotope data (\{δ\{\}\+\{18\}O\} and \{δ\{\}\+\{13\}C\}) from the freshwater snail Gyraulus sibirica (Dunker) in a 34 cm lo...Lake Xingcuo is a small closed, hard\|water lake, situated on eastern Tibet Plateau. Stable isotope data (\{δ\{\}\+\{18\}O\} and \{δ\{\}\+\{13\}C\}) from the freshwater snail Gyraulus sibirica (Dunker) in a 34 cm long, radioactive isotope\|dated sediment core represent the last 200 years of Lake Xingcuo environmental history. Carbon and oxygen isotope ratios in the shells of the freshwater snail bear information on the isotopic composition of the water in which the shells were formed, which in turn characterizes the climatic conditions prevailing during the snail’s life span. Whole\|shell and incremental growth data were collected from modern and fossil shells from Lake Xingcuo. The \{δ\{\}\+\{18\}O\} values of modern shells from Lake Xingcuo are in equilibrium with those of modern waters, while \{δ\{\}\+\{13\}C\} values are indicative of snail dietary carbon and a lake with high \{δ\{\}\+\{13\}C\}\-\{TDIC\}. By calibrating \{δ\{\}\+\{18\}O\} and \{δ\{\}\+\{13\}C\} in the shell Gyraulus sibirica (Dunker) with instrument\|measured data for the period 1954-1992, we found that the \{δ\{\}\+\{18\}O\} of the snail shells is an efficient indicator to reveal air temperature in the warmer half year instead of that around the whole year, and that there is a certain positive correlation between index\{δ\{\}\+\{18\}O\} and the running average temperature in the warmer half\|year period. Climatic variability on eastern Tibet Plateau, for the last two centuries, has been successfully inferred from the\{δ\{\}\+\{18\}O\} record in freshwater snails in the sediments of Lake Xingcuo. As such, the last 200 years of palaeoclimatic record for this region can be separated into three periods representing oscillations between warming and cooling, which are confirmed by the Guliya ice record on the Tibet Plateau.展开更多
Qinghai Lake Watershed （QLW） is a hot place of a series of ecological restoration and environmental remediation programs nowadays.However,little information is available on change of ecosystem service and economic p...Qinghai Lake Watershed （QLW） is a hot place of a series of ecological restoration and environmental remediation programs nowadays.However,little information is available on change of ecosystem service and economic practice in this area.As ecosystem service and natural capital are closely related with social and economic development,an index of concordance between environment and economy （ICEE） has been proposed to compare the annual variation rate of ecosystem service value （RESV） with that of gross domestic product （RGDP）.Using this Index,we have assessed concordance between environment and economy （CEE） for the QLW in the period 1977-2004.The result showed that from 1977 to 2004,the ecosystem service value in the QLW descended from 128.81×10 8 yuan to 127.32×10 8 yuan;In contrast,the GDP increased from 0.931×10 8 yuan to 8.856×10 8 yuan.The values of the I CEE were -1.14,-0.22,and -0.14 in the stages of 1977-1987,1987-2000 and 2000-2004,respectively.The result indicated that during the first stage 1977-1987,the relationship between environment and economy in the QLW was not concordant but at a high conflict;from 1987 to 2004,there was a low conflict between environment and economy,and the CEE appeared to increase slowly.Analysis of the assessment results showed that the national policies and industrial adjustment practice play an important role in the CEE changes.展开更多
This paper analyzes the characteristics of climate, geology and geomorphology, vegetation, and sand dune distribution in the Cuonahu Lake area beside the Qinghai-Tibet Railway. The types and causes of railway blown-sa...This paper analyzes the characteristics of climate, geology and geomorphology, vegetation, and sand dune distribution in the Cuonahu Lake area beside the Qinghai-Tibet Railway. The types and causes of railway blown-sand hazards are discussed, and the effectiveness of various sand-controlling measures is assessed. From the perspective of integrated management, a sand-controlling system that combines several engineering measures, including nylon net sand barriers, concrete sand barriers, movable-board sand barriers, sand interception ditches, gravel/rock cover, film sandbags, and permanent vegetation is most beneficial.展开更多
1 Introduction Viruses are the most abundant biological entities on Earth.They can influence the succession of individual microbial populations,biogeochemical cycles of C/N and,ultimately,microbial community structure...1 Introduction Viruses are the most abundant biological entities on Earth.They can influence the succession of individual microbial populations,biogeochemical cycles of C/N and,ultimately,microbial community structure through killing展开更多
The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics a...The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics and quality of groundwater in the basin.Based on samples collected from 35 groundwater wells in Sugan Lake Basin,the spatial distribution characteristics of groundwater chemistry,main hydrogeochemical processes and groundwater quality have been discussed in this paper by using the multivariate statistics and hydrochemistry analysis methods.The results showed that the groundwater is weakly alkaline,and its total dissolved solid(TDS)and total hardness(TH) are high,with the average values of 1244.03 mg/L and 492.10 mg/L,respectively.The types of groundwater are mainly HCO_3^--SO_4^(2-)-Ca^(2+)type in the runoff area and Cl^--SO_4^(2-)-Na^+type in the catchment area.Rock weathering and ion exchange are the main controlling factors of regional groundwater chemistry,followed by evaporative crystallization,and human activities have less impact on groundwater.The spatial difference of groundwater quality is obvious,the water quality of the catchment area is not suitable for drinking,and the suitability for plant growth is also poor.The groundwater in the runoff area can be used for drinking,but the hardness is slightly higher,which is more suitable for ecological purpose.展开更多
Most of the thermokarst lakes are spread appreciably in Beiluhe Basin,Qinghai-Tibet Plateau,China,where ice-rich permafrost exists.Two typical thermokarst lakes with differing area and depth were examined to ascertain...Most of the thermokarst lakes are spread appreciably in Beiluhe Basin,Qinghai-Tibet Plateau,China,where ice-rich permafrost exists.Two typical thermokarst lakes with differing area and depth were examined to ascertain their age.We obtained lake-bottom samples of 50 cm length from lake BLH-A and 25 cm length from lake BLH-B.Environmental 137 Cs and 210 Pb and radiocarbon age dating techniques were applied to the 50 cm and 25 cm samples,respectively.The results indicate that the initiation of BLH-A is about 800-900 a B.P.,and approximately 1,450±30 a B.P.to 2,230±30 a B.P.for BLH-B.These results will provide scientific bases for sedimentological study and thermokarst activity in Beiluhe Basin.展开更多
Lake change,as a mirror of climate change,has obvious indication and warning effect on climate.By extracting information of all lakes in Tibet Plateau from Landsat of the 1970’s,the 1990’s,around 2000 and 2010 based...Lake change,as a mirror of climate change,has obvious indication and warning effect on climate.By extracting information of all lakes in Tibet Plateau from Landsat of the 1970’s,the 1990’s,around 2000 and 2010 based on RS and GIS,and,in combination with on-the-spot investigations to a few representative lakes,the authors展开更多
1 Introduction China is a country which has many salt lakes.Tibet is the area where have numerous salt lake,because the sources of water have multiple chemical type,resulting in Tibet salt
The origin of boron in boron-rich salt lakes in the Tibetan Plateau has long been the subject of debate.The Damzung Co Salt Lake in central Tibet has high boron concentrations(B=276–313 mg/L)and is an ideal site for
Nam Co is the largest (1920 km2 in area) and highest (4718 m above sea level) lake in Tibet. According to the discovery of lake terraces and highstand lacustrine deposits at several places in Nam Co and its adjacent a...Nam Co is the largest (1920 km2 in area) and highest (4718 m above sea level) lake in Tibet. According to the discovery of lake terraces and highstand lacustrine deposits at several places in Nam Co and its adjacent areas, the authors confirm the existence of an ancient large lake in the southeastern part of the northern Tibetan Plateau. On the basis of the U-series, 14C and ESR dating, coupled with the levelling survey of lake deposits and geomorphology, the evolutionary process of the ancient large lake in the southeastern part of the northern Tibetan Plateau may fall into three stages: (1) the ancient large lake stage at 115-40 ka BP, when the ancient lake level was 140-26 m above the level of present Nam Co; (2) the outflow lake stage at 40-30 ka BP, when the ancient level was 26-19 m above the present lake level; and (3) the Nam Co stage since 30 ka BP, when the ancient lake level was < 19 m above the present lake level. During the ancient large lake stage, a large number of modern large, medium-sized and small lakes, including Nam Co, Siling Co and Zhari Namco, in the southeastern part of the northern Tibetan Plateau, were connected into a single large ancient lake, rather than several separate lakes connected by river channels. Its areal extent may have gone beyond the watersheds of the modern endorheic and exorheic drainage systems; so it may be called the 'ancient east lake', 'ancient south lake' and 'ancient west lake'. It might also be connected with other ancient lakes in the southern and western parts of the northern Tibetan Plateau to form a unified 'ancient large lake' on the northern Tibetan Plateau.展开更多
The Hohxil region in the northern Qinghai-Tibet Plateau is occupied by numerous plateau lakes, which have long been inferred as being tectonic products. However, so far little evidence has been found to support this t...The Hohxil region in the northern Qinghai-Tibet Plateau is occupied by numerous plateau lakes, which have long been inferred as being tectonic products. However, so far little evidence has been found to support this tentative inference. Field survey and morphotectonic analysis of TM satellite images in the eastern segment of the Hohxil region revealed that Kusai Lake and Yelusu Lake are S- shaped pull-apart basins, which were dominated by left strike-slip master faults trending WNW-ESE. The pull-apart distances of the two lakes are analyzed to be 〈15-20 km and 15 km respectively. Based on studies of the faulting rate, the initiation ages of the pull-apart basins are suggested to be approximately in the Early Pleistocene. The pull-apart basin tectonics is further regarded as a common mechanism for the widely distributed large lake basins in the northern Qinghai-Tibet Plateau. Regional distribution of these pull-apart basins and their substantial intra-block slip suggest that a sinistral shear stress, which is independent of the distinguished strike-slip faults, has been imposed on across the northern Qinghai-Tibet Plateau. Thus, the intra-block slip may be an important expression of the eastward extrusion of the Plateau crustal material in accommodating the ongoing continent-continent convergence between India and Eurasia. The revelation of pull-apart tectonics within the Plateau hinterland provides field evidence and a possible style of deformation for the newly proposed continuous deformation by the global positioning system （GPS） measurement across the northern Qinghai-Tibet Plateau. A model, with respect to systematic tectonic landform development, for pull- apart basins is finally proposed.展开更多
Zabuye Salt Lake in Tibet,China is a carbonate-type salt lake,which has some unique characteristics that make it different from other types of salt lakes.The lake is at the latter period in its evolution and contains ...Zabuye Salt Lake in Tibet,China is a carbonate-type salt lake,which has some unique characteristics that make it different from other types of salt lakes.The lake is at the latter period in its evolution and contains liquid and solid resources.Its brine is rich in Li,B,K and other useful minor elements that are of great economic value.We studied the concentration behavior of these elements and the crystallization paths of salts during isothermal evaporation of brine at 15℃and 25℃.The crystallization sequence of the primary salts from the brine at 25℃is halite（NaCl）→aphthitalite （3K_2SO_4·Na_2SO_4）→zabuyelite（Li_2CO_3）→trona（Na_2CO_3·NaHCO_3·2H_2O）→thermonatrite （Na_2CO_3·H_2O）→sylvite（KCl）,while the sequence is halite（NaCl）→sylvite（KCl）→trona （Na_2CO_3·NaHCO_3·2H_2O）→zabuyelite（Li_2CO_3）→thermonatrite（Na_2CO_3·H_2O）→aphthitalite （3K_2SO_4·Na_2SO_4） at 15℃.They are in accordance with the metastable phase diagram of the Na~＋,K~＋-Cl^-, CO_3^（2-）,SO_4^（2-）-H_2O quinary system at 25℃,except for Na_2CO_3·7H_2O which is replaced by trona and thermonatrite.In the 25℃experiment,zabuyelite（Li_2CO_3） was precipitated in the early stage because Li_2CO_3 is supersaturated in the brine at 25℃,in contrast with that at 15℃,it precipitated in the later stage.Potash was precipitated in the middle and late stages in both experiments,while boron was concentrated in the early and middle stages and precipitated in the late stage.展开更多
In southern Tibet, there is a series of lakes in the region (82°30'E, 29°N and 90°30'E, 33°N). This study indicates that these lakes were formed by the impact of a single disint...In southern Tibet, there is a series of lakes in the region (82°30'E, 29°N and 90°30'E, 33°N). This study indicates that these lakes were formed by the impact of a single disintegrating comet that hit the region. Observation indicates that the lakes are unusually closely aligned and have a steep slope facing circular feature on the eastern side. Fractures and faults connecting these lakes can be observed over entire subject site hinting towards the multiple impact craters. The terrain is uneven and lakes are partially filled hence in some cases do not look like circular or elliptical. These lakes vary from 1 Km to 65 Km in diameter and are linearly aligned around a single line. Studies of deuterium by Yuan et al. (2011) [1] indicate an abrupt 4‰ increase in δ18O in middle Holocene period around 6000 years ago. The study indicates that the region is rich in diamond, Coesite, Platinum Group Elements (PGE), Stishovite, tektites, and other complex alloys, as would be expected from a high energy impact of an extraterrestrial object. The possibility of the impact as one of the reasons for the diamond in this region was also suggested by Wen-Ji Bai and Qing-Song Fang (2007) [2]. However in absence of definitive evidence they favoured mantle origin. Two possible reasons of absence of impact signature are source of sample and impact pattern. First is the source of the sample which is collected from the river beds of Yarlung-Zangbo Suture Zone of Tibet which is believed to be the origin of this diamond, however it ignores the fact that these rivers get water from lakes which are in the proposed impact zone and the second reason is the impact-pattern spread over close to 800 km which is not expected from the asteroid impact. It will therefore be prudent to test samples from the lake region to understand surface distortion features to confirm the impact. Based on satellite imagery major industrial development supported by road infrastructure in the subject region near lakes and rivers originating from these lakes can be observed hinting towards placer mining activity associated with lakes (craters). Our study suggests that the diamonds, Platinum Group Elements, Stishovite and other alloys harvested from the region should be considered as comet impact diamonds rather than those created in the interior of the earth.展开更多
文摘Shorelines are widespread and lake deposits and lake geomorphology are welldeveloped on the northern Tibetan Plateau. Through field observations of lacustrine deposits of NamCo-the highest and largest Quaternary lake in Tibet, the authors found four-step shore terracescomposed of sands and clays with well-developed horizontal bedding and 3-12 m, 15-22 m, 25-30 m and35-45 m higher than the lake surface respectively, lacustrine deposits resting on the bedrocks and60-150 m higher than the lake surface, and up to approx 50 levees composed of oblate lakeshoregravels. Moreover they found lacustrine and lakeshore deposits making up the terraces and levees onthe bottoms of wide dividing valleys connecting Nam Co with the Rencoyuema, Rencogongma and Jiuru Conorthwest of Nam Co (the valley bottoms are 20 m, 90 m and 60 m higher than the above-mentionedthree lakes) and on slopes north of it, i.e. terraces II and III of Nam Co. Thus they confirm thatNam Co and Ring Co-Jiuru Co had connected with each other several times, i.e. formed a unified largelake several times, rather than had been different lakes connected only by river channels. Fromindications such as the distribution of the highest shoreline and lake deposits and geomorphology,the authors conclude that the total area of the old large lakes on the northern Tibetan Plateau is afew times larger than that of the modern lakes and that the last-stage old large lakes formed inthe interglacial interval of the last glaciation.
文摘The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake's surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+-28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.
基金supported by the National Science Foundation of China (41730854, 41877157, 41530854)the Project supported by State Key Laboratory of Loess and Quaternary Geology (SKLLQG1604)+2 种基金the Project supported by State Key Laboratory of Earth Surface Processes and Resource Ecology (2017-KF-15)the Project of Shandong Province Higher Educational Science and Technology Program (J17KA192)the National Key Research and Development Plan of Shandong Province (2018GSF117021)
文摘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 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·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.
基金funded by the Major State Basic Research Development Program of China (973 Program) under Grant No. 2010CB951701by the Natural Science Foundation of China (No. 41071042)supported by the Innovation Project of Chinese Academy of Sciences (KZCX2-YW-BR-22)
文摘Robust climate warming has led to significant expansion of lakes in the central Tibetan Plateau. Using remote sensing data, our quantitative analysis indicates that Siling Co, a saline lake in a characteristic endorheic basin in the central region of the Plateau, has expanded more than 600 km2 in area since 1976. Particularly since 1995, the lake has signif- icantly expanded in response to increasing precipitation, decreasing water surface evaporation caused by weaker winds and less solar radiation, and increased glacier meltwater draining to the lake. Glacie^lake interactions are important in governing lake expansion and are also part of a feedback loop that influences the local climate. Worsening climatic conditions （decreased precipitation and increased temperatures） that could have caused the lake to shrink during 1976-1994 were offset by increasing glacier meltwater feeding the lake, which made the lake nearly stable. We demonstrate that this pattern changed during 1995-2009, when glacier meltwater actually decreased but participation runoff increased and evaporation decreased, leading to expansion of the lake. If climatic conditions became suitable for further lake development, which would be indicated by expansion in lake area, glacier meltwater could be saved in a stable reservoir.
基金This study was supported by National Natural Science Foundation of China grant 49033010 and 40531002China Geological Survey Project 2003 1300065(Evolutionary Series of Quatemary Main Lake Environment and Climatic Change on the Qinghai-Tibet Plateau)Ministry of Science and Technology Public Welfare Research Project 2001DIA-10020.
文摘Lake geomorphology and high-level lacustrine deposits since the mid-late Pleistocene are well preserved in lakes of the Qinghai-Tibet Plateau. According to geological surveys of 17 lake districts in different locations of the plateau, combined with interpretations of satellite images and topographic maps, the authors studied the timing of formation and scopes of the pan-lake areas of the plateau and their paleoclimate. The latest two high lake levels （overflow surfaces） on the Qinghai-Tibet Plateau in the Quaternary occurred at N40 to 30/35 ka and N65 to 53 ka respectively. In these time intervals, the plateau was covered by huge interconnected pan-lake systems with a total area of -36 km^2 and a total volume of lake water of 〉530 million km^2, which are about 38 times and 659 times larger than those of the modern lakes respectively. Before this pan-lake period in the late Pleistocene, there had been three high lake levels that occurred at N 132-112 ka, 110-95 ka and 91-72/-83-75 ka respectively, suggesting that the late Quaternary climate on the plateau was unstable and changed rapidly. The -40-30 ka high lake level also appeared in the Tengger desert north of the plateau, suggesting that there existed very strong summer monsoons from South Asia then; the variation in solar radiation with a 20,000 precessional period has special importance for the high-altitude Qinghai-Tibet Plateau in the low-latitude zone of the Earth. Around 30 ka, the pan-lakes at the peripheries of the Qinghai-Tibet Plateau drained out suddenly with rapid uplift of the plateau and cooling. In a short time the huge amount of cold lake water emptied into the Indian Ocean and Western Pacific. The draining event of the pan-lakes brought about the environmental changes of rivers and lakes at peripheries of the plateau.
基金the support of the National Natural Science Foundation of China(41672243,41877198)
文摘The mineral rock salts present in the Mahai Salt Lake of the Qaidam basin exhibit high solubilities in water. In addition, the multicomponent underground brine exhibits a high salinity and is easily precipitated. In the natural state, brine transport in the brine layer is extremely slow, and the brine is in a relatively stable chemical equilibrium state with the rock salt media. However, during mining, both the seepage and the chemical fields fluctuate significantly, thereby disrupting the equilibrium and leading to variations in the chemical composition and dynamic characteristics of the brine. Therefore, we selected underground brine from the Mahai Salt Lake, collecting a total of 183 brine samples over three stages of mining（i.e., the early stage of underground brine extraction, the initial stage of mining, and the later stage of mining）. Using a range of analytical techniques, the chemical dynamics of the underground brine water and its evolution were systematically studied. We found that evaporation and enrichment were the main mechanisms of underground brine evolution in the Mahai Salt Lake, with cation exchange and mineral dissolution/precipitation being key factors in determining the dynamic characteristics and evolution of the brine.
文摘Lake Xingcuo is a small closed, hard\|water lake, situated on eastern Tibet Plateau. Stable isotope data (\{δ\{\}\+\{18\}O\} and \{δ\{\}\+\{13\}C\}) from the freshwater snail Gyraulus sibirica (Dunker) in a 34 cm long, radioactive isotope\|dated sediment core represent the last 200 years of Lake Xingcuo environmental history. Carbon and oxygen isotope ratios in the shells of the freshwater snail bear information on the isotopic composition of the water in which the shells were formed, which in turn characterizes the climatic conditions prevailing during the snail’s life span. Whole\|shell and incremental growth data were collected from modern and fossil shells from Lake Xingcuo. The \{δ\{\}\+\{18\}O\} values of modern shells from Lake Xingcuo are in equilibrium with those of modern waters, while \{δ\{\}\+\{13\}C\} values are indicative of snail dietary carbon and a lake with high \{δ\{\}\+\{13\}C\}\-\{TDIC\}. By calibrating \{δ\{\}\+\{18\}O\} and \{δ\{\}\+\{13\}C\} in the shell Gyraulus sibirica (Dunker) with instrument\|measured data for the period 1954-1992, we found that the \{δ\{\}\+\{18\}O\} of the snail shells is an efficient indicator to reveal air temperature in the warmer half year instead of that around the whole year, and that there is a certain positive correlation between index\{δ\{\}\+\{18\}O\} and the running average temperature in the warmer half\|year period. Climatic variability on eastern Tibet Plateau, for the last two centuries, has been successfully inferred from the\{δ\{\}\+\{18\}O\} record in freshwater snails in the sediments of Lake Xingcuo. As such, the last 200 years of palaeoclimatic record for this region can be separated into three periods representing oscillations between warming and cooling, which are confirmed by the Guliya ice record on the Tibet Plateau.
基金New Century Excellent Talents in University, No.NCET-08-0056 National Natural Science Foundation of China, No.40971110 National Key Technologies R＆D Program, No.2007BAC30B02
文摘Qinghai Lake Watershed （QLW） is a hot place of a series of ecological restoration and environmental remediation programs nowadays.However,little information is available on change of ecosystem service and economic practice in this area.As ecosystem service and natural capital are closely related with social and economic development,an index of concordance between environment and economy （ICEE） has been proposed to compare the annual variation rate of ecosystem service value （RESV） with that of gross domestic product （RGDP）.Using this Index,we have assessed concordance between environment and economy （CEE） for the QLW in the period 1977-2004.The result showed that from 1977 to 2004,the ecosystem service value in the QLW descended from 128.81×10 8 yuan to 127.32×10 8 yuan;In contrast,the GDP increased from 0.931×10 8 yuan to 8.856×10 8 yuan.The values of the I CEE were -1.14,-0.22,and -0.14 in the stages of 1977-1987,1987-2000 and 2000-2004,respectively.The result indicated that during the first stage 1977-1987,the relationship between environment and economy in the QLW was not concordant but at a high conflict;from 1987 to 2004,there was a low conflict between environment and economy,and the CEE appeared to increase slowly.Analysis of the assessment results showed that the national policies and industrial adjustment practice play an important role in the CEE changes.
基金supported by the China National Natural Science Foundation (Gant No. 50908152)the Special Funds from Scientific Research Institutes Technology Development and Study Projects (2008EG123206 and NCSTE-2007-JKZX-209)
文摘This paper analyzes the characteristics of climate, geology and geomorphology, vegetation, and sand dune distribution in the Cuonahu Lake area beside the Qinghai-Tibet Railway. The types and causes of railway blown-sand hazards are discussed, and the effectiveness of various sand-controlling measures is assessed. From the perspective of integrated management, a sand-controlling system that combines several engineering measures, including nylon net sand barriers, concrete sand barriers, movable-board sand barriers, sand interception ditches, gravel/rock cover, film sandbags, and permanent vegetation is most beneficial.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41002123 & 41030211)the National Basic Research Program of China (Grant No. 2011CB808800)+1 种基金State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (No. GBL11201)the Fundamental Research Funds for National University, China University of Geosciences (Wuhan)
文摘1 Introduction Viruses are the most abundant biological entities on Earth.They can influence the succession of individual microbial populations,biogeochemical cycles of C/N and,ultimately,microbial community structure through killing
基金financially supported by National Natural Science Foundation of China(41761047,41661005,41661084,41861009 and 41261104)National Natural Science Foundation innovation research group science foundation of China(41421061)Autonomous project of State Key Laboratory of Cryosphere Sciences(SKLCS-ZZ-2017)
文摘The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics and quality of groundwater in the basin.Based on samples collected from 35 groundwater wells in Sugan Lake Basin,the spatial distribution characteristics of groundwater chemistry,main hydrogeochemical processes and groundwater quality have been discussed in this paper by using the multivariate statistics and hydrochemistry analysis methods.The results showed that the groundwater is weakly alkaline,and its total dissolved solid(TDS)and total hardness(TH) are high,with the average values of 1244.03 mg/L and 492.10 mg/L,respectively.The types of groundwater are mainly HCO_3^--SO_4^(2-)-Ca^(2+)type in the runoff area and Cl^--SO_4^(2-)-Na^+type in the catchment area.Rock weathering and ion exchange are the main controlling factors of regional groundwater chemistry,followed by evaporative crystallization,and human activities have less impact on groundwater.The spatial difference of groundwater quality is obvious,the water quality of the catchment area is not suitable for drinking,and the suitability for plant growth is also poor.The groundwater in the runoff area can be used for drinking,but the hardness is slightly higher,which is more suitable for ecological purpose.
基金supported by the State Key Development Program of Basic Research of China (973 Plan,2012CB026101)the Open Foundation of Key Laboratory of Highway Construction & Maintenance Technology in Permafrost Region,CCCC First Highway Consultants Co.Ltd.the Independent Project of State Key Laboratory of Frozen Soil Engineering,CAS (Grant No.SKLFSE-ZY-14)
文摘Most of the thermokarst lakes are spread appreciably in Beiluhe Basin,Qinghai-Tibet Plateau,China,where ice-rich permafrost exists.Two typical thermokarst lakes with differing area and depth were examined to ascertain their age.We obtained lake-bottom samples of 50 cm length from lake BLH-A and 25 cm length from lake BLH-B.Environmental 137 Cs and 210 Pb and radiocarbon age dating techniques were applied to the 50 cm and 25 cm samples,respectively.The results indicate that the initiation of BLH-A is about 800-900 a B.P.,and approximately 1,450±30 a B.P.to 2,230±30 a B.P.for BLH-B.These results will provide scientific bases for sedimentological study and thermokarst activity in Beiluhe Basin.
文摘Lake change,as a mirror of climate change,has obvious indication and warning effect on climate.By extracting information of all lakes in Tibet Plateau from Landsat of the 1970’s,the 1990’s,around 2000 and 2010 based on RS and GIS,and,in combination with on-the-spot investigations to a few representative lakes,the authors
文摘1 Introduction China is a country which has many salt lakes.Tibet is the area where have numerous salt lake,because the sources of water have multiple chemical type,resulting in Tibet salt
基金supported jointly by the China Geological Survey (Grant no. 1212011085524)by the National Science Foundation of China (Grant no. 41203012)
文摘The origin of boron in boron-rich salt lakes in the Tibetan Plateau has long been the subject of debate.The Damzung Co Salt Lake in central Tibet has high boron concentrations(B=276–313 mg/L)and is an ideal site for
文摘Nam Co is the largest (1920 km2 in area) and highest (4718 m above sea level) lake in Tibet. According to the discovery of lake terraces and highstand lacustrine deposits at several places in Nam Co and its adjacent areas, the authors confirm the existence of an ancient large lake in the southeastern part of the northern Tibetan Plateau. On the basis of the U-series, 14C and ESR dating, coupled with the levelling survey of lake deposits and geomorphology, the evolutionary process of the ancient large lake in the southeastern part of the northern Tibetan Plateau may fall into three stages: (1) the ancient large lake stage at 115-40 ka BP, when the ancient lake level was 140-26 m above the level of present Nam Co; (2) the outflow lake stage at 40-30 ka BP, when the ancient level was 26-19 m above the present lake level; and (3) the Nam Co stage since 30 ka BP, when the ancient lake level was < 19 m above the present lake level. During the ancient large lake stage, a large number of modern large, medium-sized and small lakes, including Nam Co, Siling Co and Zhari Namco, in the southeastern part of the northern Tibetan Plateau, were connected into a single large ancient lake, rather than several separate lakes connected by river channels. Its areal extent may have gone beyond the watersheds of the modern endorheic and exorheic drainage systems; so it may be called the 'ancient east lake', 'ancient south lake' and 'ancient west lake'. It might also be connected with other ancient lakes in the southern and western parts of the northern Tibetan Plateau to form a unified 'ancient large lake' on the northern Tibetan Plateau.
基金supported by China Geological Survey (No.1212010610103 and 200313000005)the National Natural Science Foundation of China (No.40672137 and 40372104).
文摘The Hohxil region in the northern Qinghai-Tibet Plateau is occupied by numerous plateau lakes, which have long been inferred as being tectonic products. However, so far little evidence has been found to support this tentative inference. Field survey and morphotectonic analysis of TM satellite images in the eastern segment of the Hohxil region revealed that Kusai Lake and Yelusu Lake are S- shaped pull-apart basins, which were dominated by left strike-slip master faults trending WNW-ESE. The pull-apart distances of the two lakes are analyzed to be 〈15-20 km and 15 km respectively. Based on studies of the faulting rate, the initiation ages of the pull-apart basins are suggested to be approximately in the Early Pleistocene. The pull-apart basin tectonics is further regarded as a common mechanism for the widely distributed large lake basins in the northern Qinghai-Tibet Plateau. Regional distribution of these pull-apart basins and their substantial intra-block slip suggest that a sinistral shear stress, which is independent of the distinguished strike-slip faults, has been imposed on across the northern Qinghai-Tibet Plateau. Thus, the intra-block slip may be an important expression of the eastward extrusion of the Plateau crustal material in accommodating the ongoing continent-continent convergence between India and Eurasia. The revelation of pull-apart tectonics within the Plateau hinterland provides field evidence and a possible style of deformation for the newly proposed continuous deformation by the global positioning system （GPS） measurement across the northern Qinghai-Tibet Plateau. A model, with respect to systematic tectonic landform development, for pull- apart basins is finally proposed.
基金supported by project of K0722 from the Institute of Mineral Resources,Chinese Academy of Geological Sciences
文摘Zabuye Salt Lake in Tibet,China is a carbonate-type salt lake,which has some unique characteristics that make it different from other types of salt lakes.The lake is at the latter period in its evolution and contains liquid and solid resources.Its brine is rich in Li,B,K and other useful minor elements that are of great economic value.We studied the concentration behavior of these elements and the crystallization paths of salts during isothermal evaporation of brine at 15℃and 25℃.The crystallization sequence of the primary salts from the brine at 25℃is halite（NaCl）→aphthitalite （3K_2SO_4·Na_2SO_4）→zabuyelite（Li_2CO_3）→trona（Na_2CO_3·NaHCO_3·2H_2O）→thermonatrite （Na_2CO_3·H_2O）→sylvite（KCl）,while the sequence is halite（NaCl）→sylvite（KCl）→trona （Na_2CO_3·NaHCO_3·2H_2O）→zabuyelite（Li_2CO_3）→thermonatrite（Na_2CO_3·H_2O）→aphthitalite （3K_2SO_4·Na_2SO_4） at 15℃.They are in accordance with the metastable phase diagram of the Na~＋,K~＋-Cl^-, CO_3^（2-）,SO_4^（2-）-H_2O quinary system at 25℃,except for Na_2CO_3·7H_2O which is replaced by trona and thermonatrite.In the 25℃experiment,zabuyelite（Li_2CO_3） was precipitated in the early stage because Li_2CO_3 is supersaturated in the brine at 25℃,in contrast with that at 15℃,it precipitated in the later stage.Potash was precipitated in the middle and late stages in both experiments,while boron was concentrated in the early and middle stages and precipitated in the late stage.
文摘In southern Tibet, there is a series of lakes in the region (82°30'E, 29°N and 90°30'E, 33°N). This study indicates that these lakes were formed by the impact of a single disintegrating comet that hit the region. Observation indicates that the lakes are unusually closely aligned and have a steep slope facing circular feature on the eastern side. Fractures and faults connecting these lakes can be observed over entire subject site hinting towards the multiple impact craters. The terrain is uneven and lakes are partially filled hence in some cases do not look like circular or elliptical. These lakes vary from 1 Km to 65 Km in diameter and are linearly aligned around a single line. Studies of deuterium by Yuan et al. (2011) [1] indicate an abrupt 4‰ increase in δ18O in middle Holocene period around 6000 years ago. The study indicates that the region is rich in diamond, Coesite, Platinum Group Elements (PGE), Stishovite, tektites, and other complex alloys, as would be expected from a high energy impact of an extraterrestrial object. The possibility of the impact as one of the reasons for the diamond in this region was also suggested by Wen-Ji Bai and Qing-Song Fang (2007) [2]. However in absence of definitive evidence they favoured mantle origin. Two possible reasons of absence of impact signature are source of sample and impact pattern. First is the source of the sample which is collected from the river beds of Yarlung-Zangbo Suture Zone of Tibet which is believed to be the origin of this diamond, however it ignores the fact that these rivers get water from lakes which are in the proposed impact zone and the second reason is the impact-pattern spread over close to 800 km which is not expected from the asteroid impact. It will therefore be prudent to test samples from the lake region to understand surface distortion features to confirm the impact. Based on satellite imagery major industrial development supported by road infrastructure in the subject region near lakes and rivers originating from these lakes can be observed hinting towards placer mining activity associated with lakes (craters). Our study suggests that the diamonds, Platinum Group Elements, Stishovite and other alloys harvested from the region should be considered as comet impact diamonds rather than those created in the interior of the earth.
