The loess plateau in northwestern China with an area of 640 000km^2, which has developed the loess deposits with a thickness up to 200m in typical areas, is regarded as a huge carbon stock like the karst area in south...The loess plateau in northwestern China with an area of 640 000km^2, which has developed the loess deposits with a thickness up to 200m in typical areas, is regarded as a huge carbon stock like the karst area in southwestern China, and plays an important role in regional(even global) carbon cycle. But the spring discharging from loess is poorly known compared with karst spring so far. The objective of this study is to ascertain the characteristics and origin of spring at Qiushe Village, Lingtai County, Gansu Province by hydro-chemical and isotopic methods. The results show that the springs including LGQ, HMQ, YYQ and CZQ are the depression spring and belong to the same shallow aquifer with the well water JZJ. There are not distinct seasonal/diurnal-scale variations on the hydro-chemical characteristics of the spring water(LGQ, HMQ, YYQ, CZQ) and groundwater(JZJ). The hydro-chemical type of groundwater is Ca·Mg-HCO_3. The D and O isotope ratios indicate that the precipitation is the main recharge source of groundwater in study area. And the results of tritium(TU) and Cl concentration suggest that the recharge cycle of groundwater may be more than 60 yrs. Our study shows that the water cycle in loess plateau including rainfall, infiltration, recharge and discharge exerts a continuous impact on carbon stock in loess, which should be paid more attention to in future research on the quantitative reconstruction of paleoclimate.展开更多
本文着重研究了兰州九洲台黄土剖面重矿物组成的基本特征.不同时代黄土地层重矿物组成具有复杂性、一致性和差异性,反映出九洲台黄土是风成的,沉积物主要来源于我国西部广泛分布古老岩石山岭和其有联系的大戈壁沙漠的风化产物,由于搬运...本文着重研究了兰州九洲台黄土剖面重矿物组成的基本特征.不同时代黄土地层重矿物组成具有复杂性、一致性和差异性,反映出九洲台黄土是风成的,沉积物主要来源于我国西部广泛分布古老岩石山岭和其有联系的大戈壁沙漠的风化产物,由于搬运营力的变化,使重矿物组分具有不均匀的特征.重矿物及 R 值表明,九洲台黄土沉积环境比东部西峰剖面和洛川剖面更邻近于来源区;黄土和古土壤层沉积时,主要反映相当干冷为主的气候条件,二者气候环境演变过程的差别很小,黄土层时常表现为冷湿相结合,古土壤时常表现为干暖相结合水热条件.马兰黄土沉积阶段,末次冰期有突出的表现.展开更多
基金supported by the Chinese National Natural Science Foundation (No.414 03107 and No.41325010)the Basic Science Research Fund from the Institute of Hydrogeology and Environmental Geology (No. SK201208)China Geological Survey Projects (No. 1212011 3005900)
文摘The loess plateau in northwestern China with an area of 640 000km^2, which has developed the loess deposits with a thickness up to 200m in typical areas, is regarded as a huge carbon stock like the karst area in southwestern China, and plays an important role in regional(even global) carbon cycle. But the spring discharging from loess is poorly known compared with karst spring so far. The objective of this study is to ascertain the characteristics and origin of spring at Qiushe Village, Lingtai County, Gansu Province by hydro-chemical and isotopic methods. The results show that the springs including LGQ, HMQ, YYQ and CZQ are the depression spring and belong to the same shallow aquifer with the well water JZJ. There are not distinct seasonal/diurnal-scale variations on the hydro-chemical characteristics of the spring water(LGQ, HMQ, YYQ, CZQ) and groundwater(JZJ). The hydro-chemical type of groundwater is Ca·Mg-HCO_3. The D and O isotope ratios indicate that the precipitation is the main recharge source of groundwater in study area. And the results of tritium(TU) and Cl concentration suggest that the recharge cycle of groundwater may be more than 60 yrs. Our study shows that the water cycle in loess plateau including rainfall, infiltration, recharge and discharge exerts a continuous impact on carbon stock in loess, which should be paid more attention to in future research on the quantitative reconstruction of paleoclimate.
文摘本文着重研究了兰州九洲台黄土剖面重矿物组成的基本特征.不同时代黄土地层重矿物组成具有复杂性、一致性和差异性,反映出九洲台黄土是风成的,沉积物主要来源于我国西部广泛分布古老岩石山岭和其有联系的大戈壁沙漠的风化产物,由于搬运营力的变化,使重矿物组分具有不均匀的特征.重矿物及 R 值表明,九洲台黄土沉积环境比东部西峰剖面和洛川剖面更邻近于来源区;黄土和古土壤层沉积时,主要反映相当干冷为主的气候条件,二者气候环境演变过程的差别很小,黄土层时常表现为冷湿相结合,古土壤时常表现为干暖相结合水热条件.马兰黄土沉积阶段,末次冰期有突出的表现.
