【摘要】 岩石的风化作用与碳循环有着极为密切的联系。韩江流域处于湿热地区,是广东省除珠江流域以外的第二大流域。对韩江水系进行了系统采样、测试分析显示,河水水化学组成以HCO3-和Ca2+为主,其次是SO24-和Na+。Gibbs图分析表明,韩江流域河水离子成分主要来源于岩石的风化释放;相关分析和因子分析则表明,蒸发盐岩、碳酸盐岩、硅酸盐岩风化过程对河水离子的贡献率分别为33.4%、27.7%和为10.5%。大气中的CO2通过参与岩石的化学风化过程对河水中溶解质的贡献率为20.2%。韩江流域河水中HCO3-有50.2%来自大气CO2,由此估算韩江流域岩石化学风化对大气CO2的消耗量为73.33×108mol/a。在主要支流中,由大到小的顺序是汀江、石窟河、宁江、五华河和梅潭河,分别为28.08×108,13.26×108,10.22×108,5.17×108和2.90×108mol/a。韩江流域岩石化学风化对大气CO2的消耗率为252.2×103mol/(km2·a)。各主要支流中岩石化学风化对大气CO2消耗率最高的是宁江,为718.55×103mol/(km2·a),其次是石窟河360.14×103mol/(km2·a),再依次递减的是五华河282.04×103 mol/(km2·a),汀江237.73×103 mol/(km2·a),梅潭河181.18×103mol/(km2·a);韩江流域的平均化学风化率为54.11 t/(km2·a),各主要支流由高到低依次为,宁江最高140.5 t/(km2·a),石窟河71.2 t/(km2·a),汀江52.39 t/(km2·a),五华河51.02 t/(km2·a),梅潭河38.04 t/(km2·a)。更多还原

【Abstract】 The weathering of the rock has a very close relationship with the carbon cycle.The Hanjiang River is the second largest river in Guangdong Province.A hot and humid climate prevails in the Hanjiang River basin.Based on tests and analysis of the samples from the Hanjiang River Basin,it is found that the chemical compositions of waters of the Hanjiang River and its tributaries are dominated by HCO-3,SO2-4,Ca2+ and Na+.Gibbs graph analysis showed that the ion compositions were mainly from chemical weathering of rocks.Correlation analysis and principal composition analysis showed that weathering processes of evaporates,carbonates,and silicate rocks contributed to the total dissolved mass of the Hanjiang River water by 33.4%,27.7% and 10.5%,respectively,and atmospheric CO2 by 20.2%.The contribution proportion of atmospheric CO2 to the HCO-3 in the river water is about 50.2%,from which the quantity of CO2 consumption is calculated to be 73.33×108 mol/a.The descending order of atmospheric CO2 consumptions of main tributaries of the Hanjiang River is the Tingjiang River,Shikuhe River,Ningjiang River,Wuhuahe River,Meitanhe River,with 28.08×108,13.26×108,10.22×108,5.17×108 and 2.90×108 mol/a,respectively.The total CO2 consumption rate is about 252.2×103 mol/(km2·a).The descending order of atmospheric CO2 consumption rates of main tributaries of the Hanjiang River is the Ningjiang River(718.55×103 mol/(km2·a)),Shikuhe River(360.14×103 mol/(km2·a)),Wuhuahe River(282.04×103 mol/(km2·a)),Tingjiang River(237.73×103 mol/(km2·a)),and the Meitanhe River(181.18×103 mol/(km2·a)).The average chemical weathering rate of the Hanjiang River is 54.11 t/(km2·a).The chemical weathering rates of main tributaries are 140.5 t/(km2·a) in the Ningjiang River,71.2 t/(km2·a) in the Shikuhe River,52.39 t/(km2·a) in the Tingjiang River,51.02 t/(km2·a) in the Wuhuahe River and 38.04 t/(km2·a) in the Meitanhe River.更多还原