Influence of Temperature and Mineral Surface Characteristics on Feldspar Weathering Rates in Natural and Artificial Systems: A First Approximation
Influence of Temperature and Mineral Surface Characteristics on Feldspar Weathering Rates in Natural and Artificial Systems: A First Approximation
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温度和矿物表面特性对自然和人工系统中长石风化速率的影响：第一个近似
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
M. Velbel
中科院分区：
文献类型：
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作者：
M. Velbel
近中性pH范围内的碱性长石水解速率在自然系统中比在实验室实验中慢3个数量级。校正自然风化和实验室系统之间的温度差异，将差异缩小了5倍。任何剩余的差异都可以通过有效表面积与总表面积之比的差异来解释;自然系统中的有效表面积与总表面积之比通常比实验室系统中的小得多。这可能至少部分地与实验制备人工制品有关，并且与自然风化的长石已经失去了大部分最具反应性的表面以形成蚀坑的事实有关。水文因素，如不均匀的访问矿物表面的软化流体也可能减少矿物表面积的比例在自然系统中反应。
Rates of alkali feldspar hydrolysis in the near-neutral pH range are up to 3 orders of magnitude slower in natural systems than in laboratory experiments. Correcting for differences in temperature between natural weathering and laboratory systems reduces the disparity by as much as a factor of 5. Any remaining disparity can be accounted for by differences in the ratio of effective surface area to total surface area; the ratio of effective-to- total surface area in natural systems is generally considerably smaller than in laboratory systems. This may be related, at least in part, to experimental preparation artifacts and to the fact that naturally weathered feldspars have lost much of their most reactive surface to the formation of etch pits. Hydrological factors such as inhomogeneous access of percolating fluids to mineral surfaces may also reduce the proportion of mineral surface area reacting in natural systems.