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1.
The variations of the meltwater runoff draining from Kartamak Glacier in Mt. Muztag Ata in China were studied by using the measured hydrological data from 1 June to 25 August 2003. The meltwater runoff is mainly affected by ambient temperature and precipitation. Meltwater and precipitation samples were collected from 10 to 23 August 2003. Their pH, EC (electric conductivity) and the major ions (Na~ , K~ , Ca~(2 ), Mg~(2 ), Cl~-, NO_3~-, SO_~4~(2-)) were determined. pH values showed a positive correlation with EC values for all samples. Meltwater samples were slightly alkaline. Sulfate and calcium were the dominant anion and cation in the measured ions, respectively. All the ion concentrations had inverse relationships with runoff or water level. In order to discuss the origins of dissolved chemical substances in the glacial meltwater, a principal component analysis was carried out. The results showed that water-rock interaction determined the ion components of the meltwater.  相似文献   

2.
肥城盆地区域地下水化学特征及水质评价   总被引:1,自引:0,他引:1       下载免费PDF全文
为了解肥城市地下水水化学特征及水质状况,选取20个地下水水质分析数据,综合运用统计分析、Piper三线图,Gibbs图及离子比值等水化学方法,分析了地下水水化学特征,基于模糊综合评价法,对地下水进行了质量评价。结果表明,研究区地下水中阳离子以Ca^2+,Mg^2+为主,阴离子则以HCO^-3,NO^-3,SO 2-4为主,阴、阳离子分别存在HCO^-3>NO^-3>SO 2-4>Cl-和Ca^2+>Mg^2+>Na^+>K^+的关系。TDS介于325.0~1720.0 mg/L之间,均值为741.55 mg/L。地下水呈弱碱性,且属高硬水。地下水化学类型以HCO 3-Ca,HCO 3·SO 4-Ca为主,水-岩作用是地下水水化学组分的主要控制因素,主要受碳酸盐岩的风化溶解控制。研究区地下水以Ⅱ,Ⅲ类水为主,占65%,但Ⅴ类水所占比重也较大,占到了35%。  相似文献   

3.
Rock weathering plays an important role in studying the long-term carbon cycles and global climatic change. According to the statistics analysis, the Huanghe (Yellow) River water chemistry was mainly controlled by evaporite and carbonate weathering, which were responsible for over 90% of total dissolved ions. As compared with the Huanghe River basin, dissolved load of the Changjiang (Yangtze) River was mainly originated from the carbonate dissolution. The chemical weathering rates were estimated to be 39.29t/(km2·a) and 61.58t/(km2·a) by deducting the HCO 3 derived from atmosphere in the Huanghe River and Changjiang River watersheds, respectively. The CO2 consumption rates by rock weathering were calculated to be 120.84×103mol/km2 and 452.46×103mol/km2annually in the two basins, respectively. The total CO2 consumption of the two basins amounted to 918.51×109mol/a, accounting for 3.83% of the world gross. In contrast to other world watersheds, the stronger evaporite reaction and infirm silicate weathering can explain such feature that CO2 consumption rates were lower than a global average, suggesting that the sequential weathering may be go on in the two Chinese drainage basins. Foundation item: Under the auspices of Ministry of Science and Technology Project of China (No. G1999043075) Biography: LI Jing-ying (1974-), female, a native of Xinye of Henan Province, Ph.D., associate professor, specialized in environmental geochemistry. E-mail: wxxljy2001@public.qd.sd.cn  相似文献   

4.
The uncertainty in assessing the numerous atmospheric pollutants transported via wind from arid and semi-arid regions is affecting the glacial ecosystem. In our study area due to the complexity of the system, a prominent seasonal difference noticed among major ions(Ca~(2+), Mg~(2+), SO_4~(2-), and NO_3~-). There is a need for understanding the ions cycling as a whole and the directionality of the feedback loops in the system. Therefore, we provide an appraisal of our current hypothesis for seasonal difference in major ion concentration from snow samples for two corresponding years(2013 and 2015) at Dokriani Glacier. A systematic study of chemical compositionsin the shallow snow pit from Dokriani Glacier was undertaken for the pre-monsoon season to understand the cycling of major ions from atmosphere to solute acquisition process. The intimating connections of ions cycling in snow and its temporal behavior was observed and analyzed through various statistical tests. Among major ions, the SO_4~(2-)has the highest concentration among anions on an average considered as 14.21% in 2013 and 29.46% in 2015. On the other side Ca~(2+) is the dominant cation contributing 28.22% in 2013 and 15.3% in 2015 on average. The average ratio of Na+/Cl-was higher in 2013 whereas lower in 2015. The backward trajectory analysis suggests the possible sources of the ions transported from Central Asia through the Western Disturbance(WD) as a prominent source of winter precipitation mainly in the Central Himalaya. Ionicconcentration of Ca~(2+) in cations was highly dominated while in anion SO_4~(2-)played the major role. Factor analysis and correlation matrix suggested that, the precipitation chemistry is mostly influenced by anthropogenic, crustal, and sea salt sources over the studied region. The elemental cycling through ocean, atmosphere and biosphere opens up new ways to understand the geochemical processes operating at the glacierized catchments of the Himalaya. Moreover, increasing the field-based studies in the coming decades would also have the certain advantage in overcoming the conceptual and computational geochemical modelling difficulties.  相似文献   

5.
为查明大汶河流域中上游地区岩溶地下水水化学特征和离子来源, 基于2018年枯、丰两期采集的岩溶地下水样品水化学数据, 综合运用数理统计、相关性分析、Piper图、Gibbs图以及离子比值等方法, 对大汶河流域中上游地区岩溶地下水水化学特征及其控制因素进行了分析。结果表明,大汶河流域中上游地区枯、丰水期岩溶地下水的pH均值分别为7.6和7.5, 整体表现为弱碱性。岩溶地下水中Ca2+为占优势的阳离子, HCO3-和SO42-为主要阴离子。枯、丰期岩溶地下水中ρ(TDS)均值分别为645.4, 648.4 mg/L。按照TDS划分, 大汶河流域中上游地区岩溶地下水均属于淡水或微咸水;枯、丰水期岩溶地下水水化学类型均以HCO3·SO4-Ca为主。岩石风化作用是控制区内岩溶地下水水化学特征的主要控制因素, 碳酸盐岩和硅酸盐岩矿物的溶解是地下水主要离子的重要来源。同时, 大汶河流域中上游地区岩溶地下水还受到了比较明显的人为输入影响, 地下水中NO3-主要来自于农业生产活动。该研究成果为水资源利用提供了指导作用。   相似文献   

6.
Glaciers were solid reservoirs and important water resources in western China, but they were retreating significantly in context of global warming. Laohugou Glacier No. 12 was the largest valley glacier in Qilian Mountains. In this study, realtime kinematic (RTK) data, topographic map and WorldView-2 satellite imagery were used to measure changes in terminus, extent and volume of Laohugou Glacier No. 12. Results showed that Laohugou Glacier No. 12 was shrinking significantly since 1957. From 1960 to 2015, the terminus reduction of Laohugou Glacier No. 12 was 402.96 m (3.99%) in total, and glacier length decreased to 9.7 km from 10.1 km. Reduction of glacier area and volume were the most obvious. From 1957 to 2015, glacier area and volume decreased by 1.54 km2 (7.03%) and 0.1816 km3, respectively. Reduction trend of terminus and area was slowing in 1950 -1980s, even stable for a period in the mid-1980s, and then accelerated. Ice core analysis result and nearly meteorological station data shown an increasing trend of temperature in 1957 -2015, it was a main reason of continuous retreating of Laohugou Glacier No.12.  相似文献   

7.
GLACIER MELTWATER RUNOFF IN CHINA AND ITS NOURISHMENT TO RIVER   总被引:3,自引:0,他引:3  
GLACIERMELTWATERRUNOFFINCHINAANDITSNOURISHMENTTORIVER¥YangZhenniang(杨针娘)(LanzhouInstituteofGlaciologyandGeocryology,theChines...  相似文献   

8.
岩溶地下水是泰安市城区重要供水水源,近年来随着气候环境变化和人为活动的影响,岩溶地下水水化学特征日趋复杂,但其水化学特征及成因尚不明晰。为识别研究区地下水水化学特征、成因机制,本文采用数理统计方法、离子比值、水化学图解等方法,研究了该区岩溶地下水的水文地球化学特征。结果表明:研究区内岩溶地下水水化学类型主要为HCO3Ca型、HCO3·SO4Ca 型、HCO3·SO4·ClCa型。地下水水化学成分主要受水岩相互作用控制,以溶滤作用为主,地下水中的Ca2+、Na+、HCO-3、SO2-4主要来源于方解石、白云石的碳酸盐岩及石膏、盐岩等蒸发岩的溶解,且存在逆向的阳离子交替吸附作用,导致Ca2+含量增加,Na+含量减少,人为活动影响导致地下水中Cl-、NO-3浓度增加。研究成果为研究区内岩溶地下水的合理开发与保护提供了依据。  相似文献   

9.
Studiesshowthattheglobalsurfacetemperaturewilriseatarateof0.3℃per10ainthenextseveraldecades(Houghtonetal.,1990,1992;Shi,1995;...  相似文献   

10.
We describe a radio-echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No. 1 , in Tien Shan, China, using ground-penetrating radar (GPR). Radar data were collected with 100-MHz antennas that were spaced at 4 m with a step size of 8 m. The images produced from radar survey clearly show the continuity of bedrock echoes and the undulation features of the bedrock surface. Radar results show that the maximum ice thickness of Glacier No. 1 is 133 m, the thickness of the east branch of Glacier No. 1 averages at 58. 77 m while that of the west branch of Glacier No. 1 averages at 44. 84 m. Calculation on ice volume indicates that the ice volume of the east branch of Glacier No. 1 is 51. 87 × 106 m3 and that of the west branch of Glacier No. 1 is 20. 21 × 106 m3. The amplitude of the undulation of the bedrock surface topography revealed by radar profiles is larger than that of the glacier surface topography, indicating that the surface relief does  相似文献   

11.
岩溶关键带水文地球化学过程的研究对于科学认识其内部的演化环境与结构特征具有重要意义。岩溶水是水-岩作用后主要的信息载体, 定量分析其水化学特征及成因是揭示岩溶关键带含水系统介质环境与水动力条件的有效手段。以滇中高原岩溶关键带3个典型岩溶含水系统为研究对象, 通过对不同含水系统出露的岩溶泉进行野外采样与室内测试, 综合采用数理统计分析、水化学图解、离子比例系数与水文地球化学模拟等方法, 深入剖析了各含水系统岩溶水水化学组分特征、成因作用和含水层介质特性, 并对关键带中水循环与水化学的内在联系及规律进行了探讨。结果表明: ①HCO3-、Ca2+是各含水系统岩溶水中含量最高且来源稳定的离子组分, Mg2+是控制各含水系统水化学类型异化的关键因素; ②碳酸盐岩类的岩石风化、矿物溶解是各含水系统内岩溶水化学组分特征的主要成因作用, 岩溶水对华宁水系统含水层的溶蚀作用仍在发生, 阳离子吸附交替与硅酸盐岩类的风化溶解是区域岩溶水中Na+、K+的重要来源; ③区域岩溶的发育强度、岩溶含水层的出露条件及含水介质岩性与连通性共同塑造了滇中高原岩溶关键带不同含水系统地下水化学特性。研究成果丰富了对滇中高原岩溶关键带水文地球化学过程的认识, 为区域岩溶水资源的开发、利用与保护提供基于水化学的证据支撑。   相似文献   

12.
  1. The nonanthropogenic SO4 in the Changjiang River stems from weathering and oxidation of sulphate and sulphite minerals, while the anthropogenic SO4 here is attributed to acid rain containing H2SO4 formed by atmospheric sulphur oxides derived from the burning of fossil fuels in the region of the lower reaches. Ca and Mg are probably derived from weathering of carbonate minerals, but possibly less from weathering of silicate minerals.
  2. The Changjiang River estuary is characterized by two—layer flow based on the salinity section of the estuary, so a model of two—layer exchange of water—body in the Changjiang River estuary can be advanced.
  3. The presence of SO4 and K at stations H14 and H15 were found most likely to be due to the addition and removal processes, that of the other major consituents may be mainly controlled by physical mixing in this estuary.
  相似文献   

13.
This study used Corona KH-4A and Advanced Land Observing Satellite (ALOS) PRISM images to generate digital terrain models (DTMs) of the distal part of Imja Glacier,where a few supraglacial ponds (~0.07 km 2) expanded into the large Imja Glacier Lake (Imja Tsho,~0.91 km 2) between 1964 and 2006.DTMs and subsequently derived topographical maps with contour intervals of 1 m were created from the high-resolution images (Corona in 1964 and ALOS in 2006) in the Leica Photogrammetric Suite (LPS) platform.The DTMs and topographic maps provided excellent representation of the elevation and micro-topography of the glacier surface,such as its supra-glacial ponds/lake,surface depressions,and moraine ridges,with an error of about +/-4 m (maximum).The DTMs produced from the Corona and ALOS PRISM images are suitable for use in studies of the surface change of glaciers.The topographical maps produced from the Corona data (1964) showed that part of the dead ice in the down-glacier area was even higher than the top of the lateral moraine ridges,while the glacier surface in the up-glacier area was noticeably lower than the moraine crests.This suggests more extensive melting of glacier ice in the up-glacier area before 1964.The average lowering of the glacier surface from 1964 to 2006 was 16.9 m for the dead-ice area west of the lake and 47.4 m for the glacier surface east of the lake;between 1964 and 2002,the lake surface lowered by 82.3 m.These figures represent average lowering rates of 0.4,1.1,and 2.2 m/year for the respective areas.  相似文献   

14.
Accurate measurements of glacier elevation changes play a crucial role in various glaciological studies related to glacier dynamics and mass balance. In this paper, glacier elevation changes of Urumqi Glacier No.1 between August 2015 and August 2017 were investigated using Sentinel-1 A data and DInSAR technology. Meanwhile, the atmospheric delay error was corrected with the MODIS MOD05_L2 products. The weight selection iteration method was applied to calibrate the glacier elevation changes in the mass balance years 2015-2016 and 2016-2017. Finally, the geodetic method was employed to calculate the elevation change values of individual stakes of Urumqi Glacier No.1. Moreover, the elevation change values corrected by the weight selection iteration method were verified. Results showed as follows:(1) the elevation of Urumqi Glacier No.1 glacier affected by atmospheric delay was 1.270 cm from 2015 to 2016. The glacier elevation affected by atmospheric delay from 2016 to 2017 was 1.071 cm.(2) The elevation change value of Urumqi Glacier No.1 was-1.101 m from 2015 to 2016, and the elevation of Urumqi Glacier No.1 decreased by 1.299 m from 2016 to 2017. The overall thickness of Urumqi Glacier No. 1 was thinning.(3) By comparing the elevation change results of individual stakes with corresponding points corrected by the weight selection iteration method, the mean squared errors of difference were 0.343 m and 0.280 m between the two mass balance years, respectively.(4) The accuracy of elevation change in non-glaciated areas was 0.039 m from 2015 to 2016 and 0.034 m from 2016 to 2017. Therefore, it is reliable to use Sentinel-1 A data and the study method proposed in this paper to calculate the elevation change of mountain glaciers with very low horizontal movement.  相似文献   

15.
正交试验法在大骨节病区饮水水质研究中的应用   总被引:1,自引:0,他引:1  
本文运用正交试验法对陕西永寿等大骨节病区饮水水质及其与病情间的关系进行了研究和试验,取得了如下初步认识:1)饮用缺乏Mg~(2+)、C1~-、SO_4~(2-)、HCO_3~-、Se、Sr等组分的低矿化度水,是导致大骨节病发生的重要原因。2)水中的Na~++K~+、Mg~(2+)、Ca~(2+);C1~-、SO_4~(2-)、HCO_3~-;可溶性SiO_2、有机耗氧量、矿化度;Sr、Se、Zn等含量(或阴、阳离子毫克当量百分数)的任何一组最优组合,均可用来作为优质水的划分标准。在此基础上,确定出了非致病水的水质标准。文章还对所确定出的非致病水水质标准进行了实际验证。  相似文献   

16.
我国南方喀斯特地区岩石裸露率高、土层浅薄且分布不均,这种特殊的岩土组构如何影响水文过程对于准确估算岩溶碳通量具有重要意义。水化学径流法是计算流域尺度岩溶碳通量的常用方法,其中流域面积和流量作为2个重要参数在喀斯特地区往往难以准确获取。在普定喀斯特生态系统观测研究站设计了一组岩土比(1:1和4:1)和一组土层厚度(5,20,100 cm)共计5种岩土组构的模拟试验场。通过一个完整水文年的流量和水化学监测,定量研究了岩石裸露率和土层厚度对水文过程以及岩溶碳通量的影响。研究结果表明,5个模拟试验场岩溶碳通量平均值为(17±3) gC/m2/a,受渗漏量控制,雨季(5-10月)约占95%;岩石裸露率(2组岩土组构之间)对渗漏量的影响可达14%,且随着岩石裸露率增加,入渗系数也相应增加;土层厚度对渗漏量的影响仅在1%~2%之间。此外,对8个野外流域观测数据的分析发现,入渗系数与岩溶碳通量的相关性最为显著,说明入渗系数是喀斯特地区不同岩土组构地质背景影响和控制岩溶碳通量的主要因素,同时这种影响可能随降雨量变化而变化,即入渗系数并非常数。   相似文献   

17.
在内陆干旱区,作为重要饮用水源的地下水常面临氟含量超标问题。查明内陆干旱区高氟地下水的分布规律,了解氟在地下水中的富集过程及其影响因素,既可丰富高氟地下水的研究体系,也是保证内陆干旱区饮水安全的重要基础。以新疆阿克苏地区典型山前洪积扇——依格齐艾肯河-喀拉玉尔滚河河间地带为研究区,基于水文地球化学调查结果,刻画了高氟地下水的分布区;结合氟离子含量与特征性水化学指标间的关系,揭示了高氟地下水的成因机制。结果表明:①地下水中氟含量的变化范围为0.8~6.1 mg/L,83%的水样氟含量超过《生活饮用水卫生标准》(GB 5749-2006)规定的上限(1.0 mg/L);②总体上,氟含量沿地下水流动路径逐渐增大,低氟地下水(ρ(F-)≤1.0 mg/L)分布在国道314以北的补给区,高氟地下水(ρ(F-)>1.0 mg/L)分布在国道314以南的径流区和排泄区;③高氟地下水的水化学类型以Cl·HCO3-Na型为主,而低氟地下水则以Cl·SO4-Na型为主,高氟地下水相比于低氟地下水优势阴离子偏向于HCO3-;④地下水的pH值范围为7.9~8.9(均值为8.4),表明其处于弱碱环境中。地下水中ρ(F-)与pH值呈正相关,此外构成浅层含水层的上更新统沉积物中含有黑云母、氟磷灰石等矿物,其表面存在一定数量的可交换F-,这表明水中OH-与矿物表面F-间的阴离子交换可能对氟的富集有一定贡献;⑤地下水的F-含量与Ca2+含量呈负相关,即高氟地下水中ρ(Ca2+)小于低氟地下水。考虑到氟化钙(CaF2)是自然界中的主要含氟矿物,也是地下水中氟的主要来源,ρ(F-)与ρ(Ca2+)间的这种负相关指示着高氟地下水中可能存在去Ca2+、Mg2+作用,如阳离子交替吸附或碳酸盐岩沉淀等。研究区地下水样中ρ(F-)与ρ(Mg2+)间也呈负相关关系,且和ρ(F-)与ρ(Ca2+)间的关系高度相似,也佐证了高氟地下水中去Ca2+、Mg2+作用的存在;⑥绝大部分地下水样品都位于氯碱性指数图的负值区域,且ρ(F-)与CAI-1和CAI-2均呈较好负相关,CAI-1和CAI-2都随ρ(F-)的增大而减小,这表明高氟地下水中存在Ca2+、Mg2+与Na+间更强的交换作用,对氟富集起着重要作用。地下水中ρ(F-)与SAR间呈较好正相关关系,且高氟地下水样的SAR均值(5.71)远大于低氟地下水SAR均值(1.67),这也进一步证明高氟地下水中的Ca2+、Mg2+与含水介质的Na+间存在强烈的交替作用,对氟的富集起着重要作用;⑦所有地下水样中的萤石均处于未饱和状态,且萤石的饱和指数(SI)与F-含量间呈现较好的正相关,这表明地下水对含氟矿物(主要是萤石)的持续溶解应是导致研究区地下水中氟富集的主要原因。与之相反,研究区所有地下水样中的方解石均处于过饱和状态(SI>0)。这表明CaCO3的沉淀可能促进了CaF2的溶解,导致地下水中氟离子质量浓度增高;⑧研究区低氟地下水的δ18O值介于-11.20‰~-10.67‰间,平均值为-10.94‰,而高氟地下水的δ18O值介于-11.65‰~-11.21‰间,平均值为-11.49‰,即低氟地下水较高氟地下水富集δ18O。此外,F-质量浓度较低(ρ(F-)≤3.0 mg/L)的地下水样中δ18O值与F-质量浓度呈负相关,即低氟地下水具有更正的δ18O值;F-质量浓度较高(ρ(F-)≥4.8 mg/L)的地下水样中δ18O值与F-质量浓度的相关性不显著,随F-质量浓度的增高,δ18O值基本维持不变。以上表明蒸发浓缩作用对地下水中氟的富集贡献较小;⑨研究区地下水中ρ(F-)/ρ(Cl-)比值与ρ(F-)间呈现正相关,即ρ(F-)/ρ(Cl-)比值随ρ(F-)增高呈增大趋势,这也说明地下水中氟富集的主要原因是含氟矿物的溶解,而不是蒸发浓缩作用。此外,Gibbs图也提供了证据:研究区地下水样基本处于水岩作用主导区域,表明地下水化学特征(包括氟的富集)主要受水岩作用控制,蒸发浓缩影响很小。总之,地下水中氟的富集主要由溶解作用引起,OH-与矿物表面F-间的交换也有贡献,但蒸发浓缩作用影响微弱。含氟矿物持续溶解的驱动机制是阳离子交替吸附(地下水中Ca2+与岩土颗粒表面Na+之间)及方解石沉淀所引起的地下水中Ca2+的衰减。   相似文献   

18.
Ice and snow chemistry of alpine glaciers is crucial for the research of regional atmospheric environment change. Fresh snow samples were weekly collected from Urumqi Glacier No.1 in the Tianshan Mountains, Xin- jiang, China, and the chemical characteristics and seasonal variations of major ions, mineral dust, δ18O and trace metals were measured. Results show that the concentrations of major ions in the snow are Ca2+ SO42- NH4+ NO3- Cl- Na+ Mg2+ K+, in which Ca2+ is the dominant cation, and SO42-is the dominant anion. All major ions have close positive correlations with each other except NO3-. δ18O shows positive correlation with air temperature change during the study period. Mineral dust particle and major ionic concentrations in fresh snow have obvious seasonal change, with high concentration in spring but low concentration in summer and autumn, which indicates that the chemical mass input from Asian dust activity to snow is very significant. Temporal changes of trace metals in fresh snow, e.g., Cd, Pb, Zn, Al, Fe, have shown that human-induced pollution of central Asian region also has large contribution to the snow chemistry on alpine glaciers of the Tianshan Mountains.  相似文献   

19.
2010年以来,对研究区内水文地质背景及不同层位水质化学测试样品数据分析研究,重点阐述了微量元素Fe3+的富集与含水介质岩性、地下水的酸碱度、地层含水性和氧化还原环境的关系,认为地下水中Fe3+富集赋存的最有利的环境是变质岩类地层;碳酸盐岩和碎屑岩中水化学类型HCO3-Ca型水分布最广,碳酸盐岩的地下水中Fe3+平均含量最低;变质岩中硫酸型(包括复合型)的地下水中Fe3+的平均含量最高,对Fe3+的行为呈正相关关系。地下水中Fe3+含量赋存具以副井及其外围地区为中心高浓度分带性。  相似文献   

20.
This study was conducted to evaluate the weathering intensity of the major soils developed on igneous rocks in semiarid region of northwestern Iran.Eight parent materials were selected including monzodiorite,alkali granite,granodiorite,syenite,pyroxene diorite,hornblende andesite,pyroxene andesite,and dacite.Representative soil profiles were described and soil samples were collected and analyzed for selected chemical and physical properties and total concentrations of major elements and Zr,V,Ti and Y.Bulk densities as well as Ti,Zr and V concentrations were used to estimate the strain factors and mass balance equations were used to quantify the net result of pedogenic weathering,i.e.elemental loss and gain.The results of clay content and pedogenic iron variability as well as index of compositional variability(ICV),chemical index of alteration(CIA) and,A-CN-K and MFW ternary plots showed that the soils developed on volcanic rocks(hornblende andesite> pyroxene andesite> dacite) were more weathered than those on the plutonic parent rocks(alkali granite,granodiorite,monzodiorite,syenite,pyroxene diorite).The results of mass balance calculations based on the strain factors revealed that the Ca and Na depleted during weathering progress mostly from plagioclase grains.In the semiarid regions Ca is precipitated as pedogenic calcite in the soil horizons.K and Mg depletion is less than Ca and Na especially in the profiles on the hornblende andesite with the highest clay and LOI content.The results of this study clearly suggest that the behavior of K and Mg during the weathering cannot only be explained by the disintegration of the primary minerals,since they are fixed on the secondary clay minerals.Iron did not change in the soils compared to the parent material and was precipitated as the pedogenic iron and conserved in the soil horizons.Overall,the results on the weathering indicators and major elements mass balance enrichment/depletion in the study area confirmed that the soil profiles developed on volcanic rocks are more weathered than those on the plutonic igneous rocks.  相似文献   

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