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在全球碳循环的研究中,硅酸盐化学风化被认为是大气CO_2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”CO_2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”CO_2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HCO_3~-,但并未构成大气碳汇;(4)玄武岩流域中参与岩石风化的CO_2并非全部来自大气和土壤,其中一部分可能来自深源CO_2,而深源CO_2参与形成的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.
In the study of global carbon cycle, silicate chemical weathering is considered as an important sink of atmospheric CO 2 Since basaltic weathering of basalt (a type of silicate rock) by Gislason in 1996 has been studied, weathering of basalt Based on a comprehensive and systematic review of related literatures, it is found that the so-called “atmosphere” CO 2 high consumption (carbon sequestration) in basalt basins may be related to the following reasons: (1) The basalt area with higher carbon flux is mostly located in the tropical or ocean island-island arc area, with abundant rainfall and large river runoff, resulting in a large carbon flux. (2) Of dissolved inorganic carbon (DIC) concentration does not come from the weathering of silicate minerals but rather from the rapid weathering of trace carbonate minerals widely distributed in silicate rocks, which should be attributed to the weathering of rocks by carbonate weathering (3) Exogenous acid dissolves trace carbonate minerals and contributes HCO 3 - - but does not constitute atmospheric carbon sink; (4) Not all CO 2 involved in rock weathering in the basalt basin comes from the atmosphere and soil , Some of which may come from deep source CO_2, and deep source CO_2 to participate in shape The DIC not only can not be classified as atmospheric carbon sink but rather carbon source, indicating whether basalt weathering is an important carbon sink mechanism deserves further study.