Geochemical Evidence of Gas Sources of CO_2-Rich Cold Springs from Wudalianchi,Northeast China

作     者：毛绪美 王焰新 Oleg V Chudaev 王逊 MAO XUMEI;WANG YANXIN KEY LABORATORY OF BIOGEOLOGY AND ENVIRONMENTAL GEOLOGY OF MINISTRY OF EDUCATION;CHINA UNIVERSITY OF GEOSCIENCES;WUHAN;CHINA OLEG V CHUDAEV FAR EAST GEOLOGICAL INSTITUTE;RUSSIAN ACADEMY OF SCIENCE;VLADIVOSTOK;RUSSIA WANG XUN INSTITUTE OF HYDROGEOLOGY AND ENGINEERING GEOLOGY OF HEILONGJIANG PROVINCE;HARBIN;CHINA

作者机构：Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of GeosciencesWuhan Far East Geological Institute Russian Academy of Science Institute of Hydrogeology and Engineering Geology of Heilongjiang Province 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：2009年第20卷第6期

页      面：959-970页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Nos.40425001 40602031 40830748) and Russian Fund for Basic Research 

主　　题：δ^13C δ^18O, ^3He/^4He mineral spring CO2 Wudalianchi Northeast China. 

摘      要：CO2-rich cold springs occur near the active volcanoes at Wudalianchi （五大连池）, Northeast China. The springs are rich in CO2, with HCO3-as the predominant anion and have elevated contents of total dissolved solid （TDS） （〉1 000 mg/L）, Fe^2＋ （〉20 mg/L）, Sr （〉1 mg/L）, and dissolved Si （〉20 mg/L）. The compositions of escaped and dissolved gases of the springs are similar. The δ^13C values of escaped gases and dissolved gases in mineral springs at Wudalianchi vary from -8.77‰ to -4.53‰ and -8.24‰ to -5.26‰, while δ^18O values vary from -10.68‰ to -7.65‰ and -10.30‰ to -8.84‰, respectively, indicating the same upper mantle origin of CO2 of escaped gases and dissolved gases in the springs. Carbon and oxygen isotope fractionations and water-CO2 exchange were weak in the process of groundwater flow. The 4He content exceeds 5 000×10-6 cm^3·STP/mL in escaped gases of the mineral springs, and the 3He/4He ratios of the escaped and dissolved gases vary from 2.64Ra to 3.87Ra and 1.18Ra to 3.30Ra, respectively. It can be postulated that the CO2 of mineral springs deriving from the magma chamber of the upper mantle moves upward to the surface, to increase the content of 4He in the mineral springs and decrease the ratio of 3He/4He. The helium origin of escaped gases in springs can be calculated with the MORB-crust mixing model, but that in the north spring can be better explained with the MORB-crust-air mixing model due to the effect of mixing with surface water. However, dissolved helium in springs, except the north spring, is better explained with the MORB-crust-ASW mixing model.