Hydrogen isotopic compositions of four am-phibole grains from three pieces of Iherzolite xenoliths in Cenozoic basanites of Nushan, eastern China have been analyzed by ion microprobe. σD values of all analyzed points...Hydrogen isotopic compositions of four am-phibole grains from three pieces of Iherzolite xenoliths in Cenozoic basanites of Nushan, eastern China have been analyzed by ion microprobe. σD values of all analyzed points range from -94‰ to +46‰, some of which are much higher than the highest σD (+8‰) reported previously for mantle materials. The heterogeneities of D/H ratios within single grains have been observed, the variation of σD is up to 80‰ on the scale of less than 400 μm. No correlation between hydrogen isotopic ratios and hydrogen contents can be found, implying that the scatter of σD values could not result from a late shallow process such as hydrogen loss or hydrothermal alterations and should be considered as inherited from the source at depth. Chemical compositions of Nushan amphi-boles are very homogeneous, excluding the fact that the scatter of σD values could arise from variable fractionation factors between a single fluid source and minerals. Therefore, metasomatic fluids展开更多
Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are use...Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.展开更多
基金the Nalional Natural Science foundation ot China (Grant Nos. 49803002 and 49773181).
文摘Hydrogen isotopic compositions of four am-phibole grains from three pieces of Iherzolite xenoliths in Cenozoic basanites of Nushan, eastern China have been analyzed by ion microprobe. σD values of all analyzed points range from -94‰ to +46‰, some of which are much higher than the highest σD (+8‰) reported previously for mantle materials. The heterogeneities of D/H ratios within single grains have been observed, the variation of σD is up to 80‰ on the scale of less than 400 μm. No correlation between hydrogen isotopic ratios and hydrogen contents can be found, implying that the scatter of σD values could not result from a late shallow process such as hydrogen loss or hydrothermal alterations and should be considered as inherited from the source at depth. Chemical compositions of Nushan amphi-boles are very homogeneous, excluding the fact that the scatter of σD values could arise from variable fractionation factors between a single fluid source and minerals. Therefore, metasomatic fluids
基金supported by the National Natural Science Foundation of China (Grant Nos. 91325102, 91025016 and 91125025)the National Science & Technology Support Project (No. 2011BAC07B05)
文摘Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.
