中文摘要：

在全球碳循环的研究中,硅酸盐化学风化被认为是大气CO2的一个重要汇.自1996年Gislason开展对冰岛玄武岩（硅酸盐岩的一种）风化碳汇的研究以来,玄武岩风化引起的＂大气＂CO2高消耗更成为研究热点.在对相关文献进行全面系统梳理的基础上,发现玄武岩流域的所谓＂大气＂CO2高消耗（碳汇）可能与下述原因有关：（1）碳通量较高的玄武岩研究区多位于热带或洋岛-岛弧地区,该区雨量充沛,河流径流量大,进而造成碳通量较大;（2）硅酸盐岩流域高的溶解无机碳（DIC）浓度并非来自硅酸盐矿物的风化,而是来自广泛分布在硅酸岩中的痕量碳酸盐矿物的快速风化,而这应该归为碳酸盐风化对岩石风化碳通量的贡献;（3）外源酸溶解痕量碳酸盐矿物,贡献HCO3~-,但并未构成大气碳汇;（4）玄武岩流域中参与岩石风化的CO2并非全部来自大气和土壤,其中一部分可能来自深源CO2,而深源CO2参与形成的DIC不仅不能归为大气碳汇,反而是碳源.由此可见玄武岩风化是否是一个重要的碳汇机制值得进一步研究厘定.

英文摘要：

In the science of global change, a main focus of researchers who investigate the global carbon cycle is determining the fate of missing carbon sinks. Because atmospheric CO2 that is consumed by carbonate chemical weathering is thought to return to the atmosphere through the precipitation of carbonate, it is widely accepted that it is silicate weathering, rather than carbonate weathering, that constitutes the major mechanism of atmospheric CO2 consumption. In particular, the chemical weathering of basalt, which is a type of silicate rock, is considered to be an important ＂carbon sink＂ due to the CO2 drawdown that occurs during the basalt-carbonic acid reaction. However, the high CO2 consumption rates of basalt chemical weathering may also derive from the following four aspects, as identified in the extant literature. First, study areas with high carbon fluxes （CF） are usually ocean islands, volcanic arcs or situated in tropical regions, where precipitation is high, which results in large runoff depth. This may be one of the primary reasons for the high CF, since CF is equal to the product of the runoff depth and the concentration of bicarbonate. In addition, because of the presence of chemostatic behaviors of the concentration of bicarbonate, CF is mainly determined by runoff depth. In other words, high runoff depth will directly result in high CF. Furthermore, the interface between water and minerals will be enlarged, while the saturation state of water will be decreased, by the increase of runoff depth. Therefore, more minerals will take part in the dissolution, and the dissolving capacity of water will be increased. However, this kind of high CF results from high runoff depth, rather than basaltic properties. Second, the high concentration of dissolved inorganic carbon （DIC） may result from the chemical weathering of trace amounts of carbonate dispersed in silicate rock, rather than silicate minerals. This should be regarded as the contribution of carbonate chemical weathering, rather than silicate