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测定了嫩江水系河水主要离子组成(Ca2+、Mg2+、Na+、K+、HCO3-、SO42-、Cl-),分析了不同类型岩石风化、大气降水、人为输入对河水溶解质的相对贡献,并对整个流域以及各子流域的岩石风化速率和CO2消耗速率进行了估算。结果表明,嫩江水系河水呈弱碱性,pH平均值为7.5;阳离子以Ca2+为主,约占阳离子总量的50%;阴离子以HCO3-为主,约占阴离子总量的85%。河水中的阳离子主要来源于硅酸盐岩风化(约38%)和碳酸盐岩风化(约32%),其余来源于蒸发岩溶解(约25%)和人类活动(约5%)以及大气降水输入(<1%)。嫩江流域硅酸盐岩风化速率约为1.37t·km-2·a-1(TDS硅酸盐岩),硅酸盐岩风化对大气CO2的消耗速率约为40.1×103mol·km-2·a-1。
The main ion composition (Ca2 +, Mg2 +, Na +, K +, HCO3-, SO42-, Cl-) of the river water in Nenjiang River system was measured. The relative contribution of different types of rock weathering, atmospheric precipitation and anthropogenic input to river water dissolution was analyzed. The rates of rock weathering and CO2 depletion in the basin and each sub-basin were estimated. The results show that the river water in the Nenjiang River is weakly alkaline with an average pH value of 7.5; the cation is mainly Ca2 + accounting for about 50% of the total cation; the anion is mainly HCO3- accounting for about 85% of the total anion. The cations in the river water mainly come from the weathering of silicate rocks (about 38%) and the weathering of carbonate rocks (about 32%), while the rest come from evaporite dissolution (about 25%) and human activities (about 5%), as well as the atmosphere Precipitation input (<1%). The weathering rate of silicate rocks in Nenjiang River Basin is about 1.37t · km-2 · a-1 (TDS silicate rock), and that of silicate weathering to atmospheric CO2 is about 40.1 × 103mol · km-2 · a -1.