首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
中国冰川区表碛厚度估算及其影响研究进展   总被引:5,自引:1,他引:4  
张勇  刘时银 《地理学报》2017,72(9):1606-1620
表碛覆盖型冰川是中国西部分布较为广泛的冰川类型,其典型特征是冰川消融区部分或全部覆盖了一层厚度不一的表碛。与裸冰或雪相比,表碛覆盖层下冰的融化过程有独特性,表碛厚度空间分布对一条冰川的消融、物质平衡和径流过程的影响有别于无表碛覆盖型冰川。本文回顾了近年来表碛厚度分布及其影响的研究,通过对这些进展进行总结以进一步明晰表碛影响研究的方向;同时着重介绍了近期发展的基于遥感影像热红外波段和可见光近红外波段、大气—表碛层—冰川界面能量平衡过程的表碛厚度估算方法和表碛覆盖综合评估模型,结合地面观测,分析了以遥感反演的表碛层热阻系数表征表碛厚度的精度,介绍了这类模型在表碛覆盖型冰川物质平衡和径流研究中的应用效果,以及在综合评估流域/区域尺度表碛影响的应用情况,并分析了该模型存在的不足及进一步改进的研究方向,为实现中国西部区域表碛影响的系统评估奠定基础,从而提升对区域水资源和冰川灾害的模拟和预测能力。  相似文献   

2.
廖海军  刘巧  钟妍  鲁旭阳 《地理学报》2021,76(11):2647-2659
表碛覆盖型冰川是中国西部较为常见的冰川类型。表碛层存在于大气—冰川冰界面,强烈影响大气圈与冰冻圈之间的热交换。表碛厚度的空间异质性可极大地改变冰川的消融率和物质平衡过程,进而影响冰川径流过程和下游水资源。基于Landsat TM/TIRS数据,运用能量平衡方程反演了贡嘎山地区冰川表碛厚度,研究了贡嘎山地区冰川在1990—2019年间表碛覆盖范围及厚度变化情况,同时对比了东西坡差异。结果表明:① 贡嘎山地区冰川表碛扩张总面积达43.824 km2。其中,海螺沟冰川扩张2.606 km2、磨子沟冰川1.959 km2、燕子沟冰川1.243 km2、大贡巴冰川0.896 km2、小贡巴冰川0.509 km2、南门关沟冰川2.264 km2,年均扩张率分别为3.2%、11.1%、1.5%、0.9%、1.0%和6.5%;② 海螺沟冰川、磨子沟冰川、燕子沟冰川、大贡巴冰川、小贡巴冰川、南门关沟冰川表碛平均增厚分别为5.2 cm、3.1 cm、3.7 cm、6.8 cm、7.3 cm和13.1 cm;③ 西坡冰川表碛覆盖度高,表碛覆盖年均扩张率低,冰川末端退缩量小;东坡冰川表碛覆盖年均扩张率高,但表碛覆盖度总体低于西坡,冰川末端退缩量大。  相似文献   

3.
The extensive debris that covers glaciers in the ablation zone of the Himalayan region plays an important part in regulating ablation rates and water availability for the downstream region. The melt rate of ice is determined by the amount of heat conducted through debris material lying over the ice. This study presents the vertical temperature gradients, thermal properties in terms of thermal diffusivity and thermal conductivity, and positive degree-day factors for the debris-covered portion of Lirung Glacier in Langtang Valley, Nepal Himalaya using field-based measurements from three different seasons.Field measurements include debris temperatures at different debris thicknesses, air temperature, and ice melt during the monsoon(2013), winter(2013), and pre-monsoon(2014) seasons. We used a thermal equation to estimate thermal diffusivity and thermal conductivity, and degree-day factors(DDF) were calculated from cumulative positive temperature and ice melt of the measurement period. Our analysis of debris temperature profiles at different depths of debris show the daily linear gradients of-20.81 °C/m, 4.05 °C/m, and-7.79 °C/m in the monsoon, winter, and pre-monsoon seasons, respectively. The values of thermal diffusivity and thermal conductivity in the monsoon season were 10 times greater than in the winter season. The large difference in these values is attributed to surface temperature and moisture content within the debris. Similarly, we found higher values of DDFs at thinner debris for the pre-monsoon season than in the monsoon season although we observed less melting during the pre-monsoon season. This is attributed to higher cumulative temperature during the monsoon season than in the pre-monsoon season. Our study advances our understanding of heat conductivity through debris material in different seasons, which supports estimating ice melt and discharge from glacierized river basins with debris-covered glaciers in the Himalayan region.  相似文献   

4.
基于第二次冰川编目的中国冰川现状   总被引:27,自引:6,他引:21  
以2004年之后的Landsat TM/ETM+和ASTER遥感影像为基础,参考第一次中国冰川目录及其他文献资料,经过影像校正、自动解译、野外考察、人工修订、交互检查和成果审定等技术环节,完成占全国冰川总面积85.5%的现状冰川编目,确定中国目前共有冰川48571条,总面积约5.18×104βkm2,约占全国国土面积的0.54%,冰川储量约4.3~4.7×103βkm3。中国冰川数量和面积分别以面积<0.5βkm2的冰川和面积介于1.0~50.0βkm2的冰川为主,面积最大的冰川是音苏盖提冰川(359.05βkm2)。中国西部14座山系(高原)均有冰川分布,其中昆仑山冰川数量最多,其次是天山、念青唐古拉山、喜马拉雅山和喀喇昆仑山,这5座山系冰川数量占全国冰川总数量的72.3%;冰川面积和冰储量位列前3位的山系分别为昆仑山、念青唐古拉山和天山,尽管喀喇昆仑山冰川数量和面积均小于喜马拉雅山,但前者冰储量高于后者。从冰川海拔分布来看,海拔4500~6500βm之间是冰川集中发育区域,约占全国冰川总面积的4/5以上。冰川资源在各流域分布差异显著,东亚内流区(5Y)是中国冰川分布数量最多、面积最大的一级流域,约占全国冰川总量的2/5以上;黄河流域(5J)是冰川数量最少、规模最小的一级流域,仅有冰川164条,面积126.72βkm2。新疆和西藏的冰川面积和冰储量约占全国冰川总面积的9/10。  相似文献   

5.
李治国  芦杰  史本林  李红忠  张延伟  李琳 《地理研究》2015,34(11):2095-2104
采用1:5万地形图、Landsat MSS/TM/ETM+/OLI遥感影像及数字高程模型数据,利用遥感和地理信息系统技术,并结合狮泉河、和田和于田3个气象站点1968-2013年的气温、降水量数据对松木希错流域的冰川、湖泊面积变化及其原因进行分析。结果表明:① 1968-2013年流域冰川面积不断退缩,由139.25 km2减少至137.27±0.02 km2,共减少1.98±0.02 km2,减少百分比为1.42%,2001年以后冰川退缩速度加快;② 1968-2013年松木希错面积不断扩张,由25.05 km2增加至32.62±0.02 km2,共扩张7.57±0.02 km2,扩张百分比为30.22%,且2001年之后扩张速率加快,在年代际上与冰川的退缩具有较好的耦合性;③ 1968-2013年湖面潜在蒸散量减少和降水增加分别是导致湖泊扩张的第一和第二影响因素,而升温引起的冰川、冻土融水增加有一定贡献,但影响较小且在年际尺度上不显著。  相似文献   

6.
1959年来中国天山冰川资源时空变化   总被引:1,自引:0,他引:1  
基于两期冰川编目数据与气象数据,对天山1959年来冰川资源的时空变化特征进行研究。研究发现:① 天山地区现有冰川7934条,面积7179.77 km2,冰储量756.48 km3。冰川数量以面积< 1 km2的冰川居多,面积以1~10 km2和≥ 20 km2的冰川为主,冰川集中分布在海拔3800~4800 m之间。② 在四级流域中,阿克苏河流域冰川面积最大为1721.75 km2,面积最小的是伊吾河流域,为56.03 km2。在各市(州)中,阿克苏地区冰川资源量最多,其面积和储量分别占天山总量的43.28%和68.85%;冰川资源量最少的市(州)是吐鲁番地区,面积和储量仅占天山总量的0.23%和0.07%。③ 1959年来,天山地区冰川面积减少了1619.82 km2(-18.41%),储量亏损了104.78 km3(-12.16%),其中数量以< 1 km2的冰川减少最多,面积减少以< 5 km2的冰川最为严重。④ 冰川变化呈现明显的区域差异,变化速度最快的是天山东段博格达北坡流域,变化最慢的是中部的渭干河流域。初步分析认为夏季气温显著上升带来的消融大于年内降水带来的积累是天山冰川退缩的主要原因。  相似文献   

7.
The ablation rate under a debris layer is very difficult to measure directly at debris-covered glaciers, because the surface is highly heterogeneous, and the ablation rate varies tremendously from place to place. Heat budget considerations with a debris layer on top of glacier ice suggested that 'thermal resistance' of the debris layer could be estimated from surface temperature and the heat fluxes at the debris surface, and the ablation rate of the underlying glacier ice from the thermal resistance and meteorological data. The method was tested at the Lirung Glacier in Langtang Valley, Nepal Himalayas, using the thermal band of LANDSAT satellite for estimating surface temperature distribution of the debris top surface. The amount of melt water thus estimated was compatible with the observed discharge data from the glacier basin for periods of the monsoon season in 1985 and the pre-monsoon to the monsoon season in 1996. The investigation also revealed that the amount of discharge was much larger than the amount of precipitation over the basin, and it was suggested that the melt water from the debris-covered glacier contributes significantly to the river flow as a result of the shrinkage of the glacier.  相似文献   

8.
The precise glacier boundary is a fundamental requirement for glacier inventory,the assessment of climate change and water management in remote mountain areas.However,some glaciers in mountain areas are covered by debris.The high spatial resolution images bring opportunities in mapping debris-covered glaciers.To discuss the capability of Chinese GaoFen-1 satellite lacking the short wave infrared band and thermal infrared band in mapping glaciers,this study distinguished supraglacial terrain from surrounding debris by combining GaoFen-1(GF-1)wide-field-view(WFV)images,the ratio of the thermal infrared imagery and morphometric parameters(DEM and slope)with 30 m resolution.The overall accuracy of 90.94%indicated that this method was effective for mapping supraglacial terrain in mountain areas.Comparing this result with the combination of GF-1 WFV and low-resolution morphometric parameters shows that a high-quality DEM and the thermal infrared band enhanced the accuracy of glacier mapping especially debris-covered ice in steep terrain.The user's and producer's accuracies of glacier area were also improved from 89.67%and 85.95%to 92.83%and 90.34%,respectively.GF data is recommended for mapping heavily debris-covered glaciers and will be combined with SAR data for future studies.  相似文献   

9.
基于天山托木尔峰青冰滩72号冰川2008年高精度差分GPS测量资料,2009年末端重复测量数据以及1964年地形图,通过对比研究近45 a来该冰川的变化特征,结果表明:1964~2009年,青冰滩72号冰川末端退缩1 852 m,年均后退41 m,由此造成面积减少约为1.53 km2,年均减少0.03 km2;1964~2008年,冰舌平均减薄9.59±6 m,年均减薄约0.22±0.14 m,冰储量亏损达14.1±8.8×10-3 km3(12.7±7.9×10-3 km3 w.e.)。与天山其它区域典型监测冰川相比,青冰滩72号冰川消融强烈,是区域气候、末端海拔、冰川类型、表碛覆盖等因素综合影响的结果。  相似文献   

10.
喀喇昆仑山区冰川由于存在正物质平衡或跃动、前进现象,被称之为“喀喇昆仑异常”,不过该地区冰川变化差异显著,尤其是大型表碛覆盖冰川,呈现与其他类型冰川明显的差异性响应,为理解喀喇昆仑冰川异常的机理,冰川尺度的详细变化研究十分必要。音苏盖提冰川位于喀喇昆仑山乔戈里峰北坡,是中国面积最大的冰川,是典型的大型表碛覆盖冰川。通过应用TanDEM-X/TerraSAR-X(2014年2月)与SRTM-X DEM(2000年2月)的差分干涉测量方法计算音苏盖提冰川表面高程变化,并结合冰川表面流速对冰川表面高程变化和跃动进行分析和讨论。结果表明:2000—2014年音苏盖提冰川表面高程平均下降了1.68±0.94 m,即冰川整体厚度在减薄,年变化率为-0.12±0.07 m·a-1。冰川表面高程变化分布不均,其中南分支(S)冰流冰川整体减薄较为显著,冰川南分支冰流运动速度较快,前进/跃动的末端占据了冰川的主干,阻滞原主干冰川物质的向下运移(跃动),导致原主干冰舌表面高程上升;冰川厚度减薄随着海拔升高先下降后保持稳定,同时呈现一定的波动性;低海拔表碛区域消融大于裸冰区,可能存在较薄表碛,因热传导高、覆盖大量冰面湖塘和冰崖存在,加速了冰川消融;在坡度小于30 °的区域,冰川厚度减薄随着坡度的减小而加剧;坡向朝南冰川厚度略微增加(0.01 m),西南坡向冰川厚度略微减薄(-0.03 m),其他坡向冰川厚度减薄明显。近14 a来,表碛覆盖的音苏盖提冰川表面高程整体下降表明物质处于亏损状态,冰川跃动导致局部冰川表面高程的增加。  相似文献   

11.
Glaciers in Svalbard: mass balance, runoff and freshwater flux   总被引:4,自引:1,他引:4  
Gain or loss of the freshwater stored in Svalbard glaciers has both global implications for sea level and, on a more local scale, impacts upon the hydrology of rivers and the freshwater flux to fjords. This paper gives an overview of the potential runoff from the Svalbard glaciers. The freshwater flux from basins of different scales is quantified. In small basins (A < 10 km2), the extra runoff due to the negative mass balance of the glaciers is related to the proportion of glacier cover and can at present yield more than 20% higher runoff than if the glaciers were in equilibrium with the present climate. This does not apply generally to the ice masses of Svalbard, which are mostly much closer to being in balance. The total surface runoff from Svalbard glaciers due to melting of snow and ice is roughly 25 ± 5 km3 a−1, which corresponds to a specific runoff of 680 ± 140 mm a−1, only slightly more than the annual snow accumulation. Calving of icebergs from Svalbard glaciers currently contributes significantly to the freshwater flux and is estimated to be 4 ± 1 km3 a−1 or about 110 mm a−1.  相似文献   

12.
利用环境磁学的方法可以有效地示踪河流沉积物的物源,对渭河宝鸡市区段干流及其支流河床沉积物全面系统的磁学特征分析表明:渭河干流和支流沉积物的磁性矿物含量总体相对较高,磁性矿物类型主要以亚铁磁性矿物磁铁矿和磁赤铁矿为主,同时存在不完全反铁磁性矿物赤铁矿,磁晶粒以PSD(假单畴)和MD(多畴)颗粒为主。渭河干流沉积物的磁性特征在空间上表现出了一定的差异,根据χARM/χ(非磁滞剩磁磁化率/磁化率)值的变化规律将渭河宝鸡市区段沉积物的来源分成了两段,第一段从宝鸡峡到神龙大桥,沉积物χARM/χ 值逐渐减小,磁性颗粒逐渐变粗;第二段从神龙大桥到千河入渭口,沉积物χARM/χ 值逐渐增大,沉积物的颗粒呈现出由粗变细的特征,指示了渭河宝鸡市区段河流沉积物存在一定的物源差异,渭河宝鸡市区段干流沉积物的物质来源主要以上游携带为主导,从神龙大桥向下游,支流对河床沉积物具有一定的贡献,北岸比南岸流域贡献的物质相对较多。  相似文献   

13.
Taking advantage of heat absorbing and releasing capability of phase change material (PCM),Paraffin wax-based concrete was prepared to assess its automatic temperature control performance.The mechanical properties of PCM concrete with eight different Paraffin wax contents were tested by the cube compression test and four-point bending test.The more Paraffin wax incorporated,the greater loss of the compressive strength and bending strength.Based on the mechanical results,four contents of Paraffin wax were chosen for studying PCM concrete's thermal properties,including thermal conductivity,thermal diffusivity,specific heat capacity,thermal expansion coefficient and adiabatic temperature rise.When the Paraffin wax content increases from 10% to 20%,the thermal conductivity and the thermal diffusivity decrease from 7.31 kJ/(m·h·℃) to 7.10 kJ/(m·h·℃) and from 3.03×10~(-3)m~2/h to 2.44×10~(-3)m~2/h,respectively.Meanwhile the spe‐cific heat capacity and thermal expansion coefficient rise from 5.38×10~(-1)kJ/(kg·℃) to 5.76×10~(-1)kJ/(kg·℃) and from9.63×10~(-6)/℃ to 14.02×10~(-6)/℃,respectively.The adiabatic temperature rise is found to decrease with an increasing Paraffin wax content.Considering both the mechanical and thermal properties,15%of Paraffin wax was elected for the mass con‐crete model test,and the model test results confirm the effect of Paraffin wax in automatic mass concrete temperature control.  相似文献   

14.
冀琴  刘睿  杨太保 《地理研究》2020,39(10):2403-2414
基于Landsat系列遥感数据,运用比值阈值法(B3/B5)和目视解译,研究1990—2015年喜马拉雅山冰川面积的分布与变化特征。结果表明:25年间研究区冰川面积共减少2553.10 km2,年均退缩率为0.44%/a,研究时段冰川加速退缩。研究区冰川主要分布在西段地区,中段次之,东段最少,近25年来西段、东段和中段地区冰川均表现为退缩趋势,其中东段地区退缩最快,中段最慢。从地形分布和变化特征看,5°~25°范围内冰川的分布面积较多,近25年来各坡度等级冰川均在退缩,其中25°~30°之间冰川面积退缩较快,在极平缓/极陡峭地区退缩较慢。尽管8个坡向上冰川均表现为退缩趋势,但退缩幅度有所差异,北坡与西北坡冰川退缩较慢,其他坡向退缩较快。研究时段表碛物覆盖型与非表碛物覆盖型冰川均在退缩,但后者的退缩幅度较大,表明研究区表碛物在一定程度上抑制了冰川消融。  相似文献   

15.
中亚天山山区冰雪变化及其对区域水资源的影响   总被引:8,自引:2,他引:6  
邓海军  陈亚宁 《地理学报》2018,73(7):1309-1323
冰川和积雪是构成山区固体水库的主体,对区域水资源稳定性具有调节功能,但深受气候变化的影响。以中亚天山为研究区域,基于长时间序列的观测数据,分别从冰川、积雪、水储量、径流等方面进行分析,并选取阿克苏河、开都河及乌鲁木齐河3个典型流域,研究天山山区冰雪变化对流域水资源的影响。结果表明:① 冰川退缩速率与面积的函数关系为fx) = -0.53×x-0.15R2 = 0.42,RMSE = 0.086),说明小型冰川对气候变化的响应更为敏感。同时,中低海拔区域的冰川退缩速率大于高海拔区域;② 2003-2015年天山山区水储量的递减速率为-0.7±1.53 cm/a,天山中部区域的递减速率最大,这一结果与该区域冰川急剧退缩相吻合;③ 近半个多世纪以来,冰雪融水径流增加是这3个典型流域径流量增加的主要原因,其中阿克苏河增幅最大(达0.4×108 m3/a)。但自20世纪90年代中期以来,3个流域的径流量都呈减少趋势,与流域内冰川面积减少、厚度变薄及平衡线海拔升高的关系密切。研究结果揭示了气候变化驱动下的山区固态水体储量变化对流域水资源的影响机制,以期为流域水资源管理提供有价值的决策参考。  相似文献   

16.
叶如藏布流域冰川和冰湖众多,冰川融水是当地重要的淡水资源,是冰湖扩张的重要补给,冰湖溃决是当地潜在的自然灾害,因此分析该区域冰川和冰湖的现状与变化特征具有重要的现实意义。基于Landsat系列遥感影像,分析1990—2020年叶如藏布流域冰川和冰湖的分布与变化特征。结果表明:(1) 近30 a来叶如藏布流域冰川面积整体呈退缩趋势,由1990年167.80 km2退缩到2020年128.92 km2,共退缩38.88 km2,年均退缩率为0.77%·a-1,且研究区冰川主要分布在海拔5800~6400 m之间,集中分布在5°~20°的坡度上。(2) 与冰川变化趋势相反,研究时段冰湖整体表现为扩张趋势,由1990年5.72 km2增加到2020年8.81 km2,30 a共增加3.09 km2,年均增长率为1.80%·a-1。(3) 冰湖主要分布在海拔5000~5600 m范围内,坡度在0~10°分布面积较多,表碛覆盖型冰川与非表碛覆盖型冰川对冰湖有着不同程度的影响。(4) 1990—2017年叶如藏布流域温度与降水波动较大,温度整体呈上升趋势,降水量则波动下降,导致叶如藏布流域的冰川消融,冰湖扩张。通过上述研究以期为叶如藏布流域地区提供详细的冰川和冰湖面积分布与变化特征基础数据,为防灾减灾提供一定的支撑。  相似文献   

17.
近50年来中国天山冰川面积变化对气候的响应   总被引:19,自引:1,他引:18  
基于1960 年以来中国天山各流域冰川面积变化的统计分析,系统地研究了中国天山冰川面积变化对气候的响应情况。结果表明,近50 年来中国天山冰川的面积缩小了11.5%,对研究时段统一化后发现面积年均退缩率为0.31% a-1。各流域冰川面积退缩速度存在一定差异,但冰川加速消融趋势明显。天山地区14 个气象站的气温与降水量倾向率平均值分别为0.34 oC·(10 a)-1与11 mm·(10 a)-1,气温在干季增幅大而在湿季增幅略小,降水量在干季增长缓慢而在湿季增长显著,这样的气候变化趋势有助于天山冰川的退缩。  相似文献   

18.
A total of 71,177 glaciers exist on the Qinghai-Tibet Plateau, according to the Randolph Glacier Inventory (RGI 6.0). Despite their large number, glacier ice thickness data are relatively scarce. This study utilizes digital elevation model data and ground-penetrating radar thickness measurements to estimate the distribution and variation of ice thickness of the Longbasaba Glacier using Glacier bed Topography (GlabTop), a full-width expansion model, and the Huss and Farinotti (HF) model. Results show that the average absolute deviations of GlabTop, the full-width expansion model, and the HF model are 9.8, 15.5, and 10.9 m, respectively, indicating that GlabTop performs the best in simulating glacier thickness distribution. During 1980-2015, the Longbasaba Glacier thinned by an average of 7.9±1.3 m or 0.23±0.04 m/a, and its ice volume shrunk by 0.28±0.04 km3 with an average reduction rate of 0.0081±0.0001 km3/a. In the investigation period, the area and volume of Longbasaba Lake expanded at rates of 0.12±0.01 km2/a and 0.0132±0.0018 km3/a, respectively. This proglacial lake could potentially extend up to 5,000 m from the lake dam.  相似文献   

19.
1970-2016年冈底斯山冰川变化   总被引:2,自引:0,他引:2  
基于修订后的中国两次冰川编目数据及2015-2016年Landsat OLI遥感影像,对冈底斯山1970-2016年的冰川时空变化特征进行分析,并利用相应时段的气温和降水数据,对冰川变化原因进行探讨,为全面认识冈底斯山在气候变暖背景下冰川的响应规律及区域水资源合理利用提供科学依据。结果表明:① 2015-2016年冈底斯山共有冰川3953条,面积1306.45 km 2,冰储量约58.16 km 3;冰川数量以面积< 0.5 km 2的冰川为主,面积则以介于0.1~5 km 2的冰川为主。② 1970-2016年冈底斯山冰川面积共减少854.05 km 2(-39.53%),冰川面积变化相对速率高达-1.09%/a,消融期气温升高是导致该山区冰川退缩的最主要原因。与中国西部其他山系冰川变化相比,冈底斯山是冰川退缩最为强烈的地区,且近年来冰川退缩呈加快趋势。③ 冈底斯山冰川面积减少主要集中在海拔5600~6100 m之间,海拔6500 m以上区域基本没有变化。除南朝向和东南朝向外,冈底斯山其他朝向冰川数量和面积均呈减少趋势,其中北朝向冰川面积减少最多,西北朝向冰川面积变化最快。④ 冈底斯山冰川面积变化自西向东呈加快趋势,其中东段冰川面积变化相对速率高达-1.72%/a,中段次之(-1.67%/a),西段仅为-0.83%/a。  相似文献   

20.
徐莉  李艳红  杨甲全 《中国沙漠》2014,34(6):1552-1557
对罗布泊典型地区表层土磁性特征、粒度及地球化学特征的研究表明:(1)总体样品磁性矿物含量均较低;各样地间磁化率差异较为明显,阿奇克谷地西部磁化率值最高(2.1×10-7 m3·kg-1),耳轮区最低(0.47×10-7 m3·kg-1),该区磁化率值总体表现为东部略高于西部.(2)样品粒度组分总体以粉砂(2~63 μm)为主,平均约占74.17%,分选性较差,细颗粒占主导地位,且各粒度组分之间的含量变化幅度较小.(3)易溶性盐主要是由Cl-、SO4-2、Na+和K+构成,Mg2+、Ca2+含量较低,HCO3-、CO32-含量很低,易溶性盐类型主要为Cl--SO4-2-Na+和K+型;样品总有机碳平均含量约为0.66%;pH值变化范围为6.98~8.00,且耳轮区样品值均高于阿奇克谷地西部.综上所述,该区当时气候已转向干旱化趋势发展,而且气候持续干化与补给变化对该区物质形成具有一定影响,是该区物质空间分布的主要成因.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号