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河流化学蕴含着有关化学风化过程、从陆地到海洋物质输移通量以及全球碳循环的重要信息。虽然河流化学的短时间尺度(月至十年级)变化已得到广泛认识,然而由于大多数观测记录的时间跨度有限,百年及更长时间尺度河流化学的变率还很难直接评估。特别是对于高强度、低频率事件(发生频率大于百年)对河流化学影响更是难以评估,因为它们发生的频次极低。2008年汶川8.0级地震为评价这种巨大的、罕见的地质事件对河流系统水化学的影响提供了一次非常珍贵的自然实验场,特别是对于四川省境内的岷江流域。与已发表的2008年以前的数据相比,在地震后2010年上半年收集的岷江河水的溶解态元素组成表现出显著的差异。来自硅酸盐矿物的阳离子(特别是Na~+和K~+)浓度及Na/Ca和K/Ca比值均有增加,而Si~(4+)及Ca/Si比值变化很小,这表明地震时和地震后山崩/崩塌的粉碎过程形成了新鲜的硅酸盐矿物表面,从而提供易于溶解的离子进入河水。由此造成的河水化学插曲式的变化可能代表了一个以前尚未认识的过程,这对于量化长时间尺度河流溶解态物质输移和理解矿物风化过程均具有重要的指示意义。
River chemistry contains important information about chemical weathering processes, transport fluxes from land to sea and the global carbon cycle. Although the short-term scale of river chemistry (from month to tenth grade) has been widely recognized, the variability of river chemistry at centuries and longer scales can not be directly assessed due to the limited time span of most observational records. In particular, chemical impacts on rivers are more difficult to assess for high-intensity, low-frequency events (occurring at frequencies greater than a century) because they occur at very low frequencies. The 2008 Wenchuan Ms 8.0 Earthquake provided a very valuable natural experiment site for assessing the impact of this huge and rare geological event on the hydrochemistry of river systems, especially for the Minjiang River basin in Sichuan Province. Compared with the published data before 2008, the dissolved elemental compositions of the Minjiang River collected in the first half of 2010 after the earthquake show significant differences. The concentrations of cations (especially Na ~ + and K ~ +) and the ratio of Na / Ca and K / Ca from silicate minerals increased, while the changes of Si ~ (4+) and Ca / The crushing process of the landslide / collapse after the earthquake and after the earthquake formed a fresh silicate mineral surface that provided readily soluble ions into the river. The resulting change in chemical formula for river water may represent a previously unrecognized process, which is of great importance in quantifying the transport of dissolved matter in rivers over a long period of time and in understanding the weathering of minerals.