Mechanisms of hydrothermal crystallization of quartz at 250°C and 15 kbar
Mechanisms of hydrothermal crystallization of quartz at 250°C and 15 kbar
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DOI：
10.1016/0016-7037(78)90130-8
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发表时间：
1978-02
影响因子：
5
通讯作者：
Y. Matsuhisa;J. R. Goldsmith;R. Clayton
中科院分区：
文献类型：
--
作者：
Y. Matsuhisa;J. R. Goldsmith;R. Clayton
石英与水的氧同位素交换，采用一种新的技术，其中18 O/16 O和17 O/16 O分馏测量，在250°C和15 kbar下得到平衡分馏Δ18= 9.0。反应主要通过细颗粒的溶解和较大颗粒的生长进行。在这个温度下，通过固态扩散进行的交换是极其缓慢的。在相同的实验条件下，方石英的行为完全不同，在几分钟内转变为亚微米石英晶体。相变伴随着动力学同位素效应，产生与水同位素不平衡的石英。这种不平衡产物也可能在其他涉及相变或矿物合成的实验中形成。
Oxygen isotopic exchange between quartz and water, using a novel technique in which both18O/16O and17O/16O fractionations were measured, yielded an equilibrium fractionation Δ18= 9.0 at 250°C and 15 kbar. The reaction proceeds predominantly by solution of fine grains and growth of larger grains. Exchange by solid-state diffusion is immeasurably slow at this temperature. Under the same experimental conditions, cristobalite behaves quite differently, becoming transformed to sub-micron quartz crystals in a few minutes. The phase transformation is accompanied by a kinetic isotope effect yielding quartz in isotopic disequilibrium with water. It is possible that such disequilibrium products are also formed in other experiments involving phase transitions or mineral syntheses.