We measured the electrical conductivity of tremolite over a range of pressures (1.0, 1.5, and 2.0 GPa) and temperatures (648–1373 K). At temperatures lower than 1173 K, the electrical conductivity of tremolite was ~ 0.001 S/m, but once the dehydroxylation reaction took place at 1173 K, we observed a significant increase in the electrical conductivity. The electrical conductivity continued to increase until it reached its maximum value of ~ 1 S/m at a temperature of 1373 K, which we attributed to dehydroxylation in the tremolite samples. The electrical behavior was altered by the physical breakdown of the tremolite structure, rather than the oxidation process. The decomposition of tremolite resulted in the creation of diopside, enstatite, and quartz. To explain some anomalous conductivity measurements, we propose that iron-free amphibole experiences a dehydroxylation mechanism that differs from the dehydroxylation mechanism observed in iron-bearing amphiboles. Our conductivity analyses indicate that the observed increase in the electrical conductivity in deep subduction regions (at depths of ~ 180 km) is driven by the dehydroxylation of tremolite and by the mixing of lherzolite and tremolite in the upper mantle. Using our data and previously published temperature gradient data, we were able to extrapolate reasonable electrical conductivity values for the surface and interior of Venus.

中文翻译：

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高温高压下透闪石的电导率：对地球和金星高电导率异常的影响

我们在压力（1.0、1.5 和 2.0 GPa）和温度（648–1373 K）范围内测量了透闪石的电导率。在低于 1173 K 的温度下，透闪石的电导率约为 0.001 S/m，但一旦在 1173 K 下发生脱羟基反应，我们观察到电导率显着增加。电导率继续增加，直到在 1373 K 的温度下达到其最大值 ~ 1 S/m，我们将其归因于透闪石样品中的脱羟基作用。透闪石结构的物理分解改变了电学行为，而不是氧化过程。透闪石的分解导致透辉石、顽辉石和石英的产生。为了解释一些异常的电导率测量，我们提出无铁闪石经历了一种与含铁闪石中观察到的脱羟基机制不同的脱羟基机制。我们的电导率分析表明，在深俯冲区（约 180 公里的深度）中观察到的电导率增加是由透闪石的脱羟基作用以及上地幔中闪长石和透闪石的混合驱动的。使用我们的数据和之前发布的温度梯度数据，我们能够推断出金星表面和内部的合理电导率值。我们的电导率分析表明，在深俯冲区（约 180 公里的深度）中观察到的电导率增加是由透闪石的脱羟基作用以及上地幔中闪长石和透闪石的混合驱动的。使用我们的数据和之前发布的温度梯度数据，我们能够推断出金星表面和内部的合理电导率值。我们的电导率分析表明，在深俯冲区（约 180 公里的深度）中观察到的电导率增加是由透闪石的脱羟基作用以及上地幔中闪长石和透闪石的混合驱动的。使用我们的数据和之前发布的温度梯度数据，我们能够推断出金星表面和内部的合理电导率值。