酸雨对广西典型碳酸盐岩地区碳源效应研究

选取广西两个典型碳酸盐岩地区桂林(代表灰岩地区)与柳州(代表白云岩地区)作为研究区域,研究酸雨与岩石表面反应,并计算出由酸雨对碳酸盐岩的化学风化过程中形成CO2成为碳源的量。利用溶蚀试片溶蚀速率以及GIS技术得到研究区由酸雨产生的CO2源为41.066×108 g/a,其中桂林市区速率为33.349×108 g/a,柳州市区速率为7.717×108 g/a。单位面积源桂林与柳州分别为66.967×105 g/a.km2和42.777×105 g/a.km2,虽然低于两地的单位面积汇分别为273.891×105 g/a.km2与43.660×105 g/a.km2,但已不容忽略。柳州市区CO2源的释放速率比桂林市区慢的原因主要有二:桂林市区碳酸盐岩的代表面积为柳州市区2.77倍;由于柳州酸雨总体强度比桂林低,导致碳酸盐岩的溶蚀速率较低。

Research on Carbon Source Effect of Acid Rain in a Typical Carbonate Rock Area,Guangxi

In order to give insight into the reaction between acid rain and carbonate rock surface,and figure out the CO2 carbonate source amount from the processes of acid rain-induced chemical weathering of carbonate rocks,two typical carbonate rock areas Guilin(representing a limestone area) and Liuzhou(representing a dolomite area) were chosen as the study areas in Guangxi.According to the dissolution rate calculated by the limestone test piece and GIS analysis,the CO2 source produced by acid rain was 41.066×108 g/a,with 33.349×108 g/a for Guilin and 7.717×108 g/a for Liuzhou.The carbon sources of unit areas in Guilin and Liuzhou were 66.967×105 g/(km2·a) and 42.777×105 g/(km2·a),respectively.Although the carbon sources were still less than their carbon sinks in Guilin and Liuzhou,which were 273.891×105 g/(km2·a) and 43.660×105 g/(km2·a),respectively,they should not be neglected.There are two reasons to explain why the degassing rate of carbon source in Guilin is lower than that in Liuzhou.One is the representative area of carbonate rock in Guilin,where the degassing rate is 2.77 times that in Liuzhou,and the other one is that the total intensity of acid rain in Guilin is lower than in Liuzhou,so the dissolution rate of the carbonate rocks is lower in Guilin.