Here, we present new measurements of the phase stability and lattice compressibility of gaspéite (NiCO 3 ) to 50 GPa. Our study is motivated by our interest in understanding high-pressure carbonate behavior. While carbonates have been extensively studied under high-pressure and -temperature conditions, they exhibit different behaviors. We have studied the high-pressure behavior of gaspéite using diamond anvil cells, Raman spectroscopy, and X-ray diffraction. Our experimental data show that gaspéite maintains the calcite structure up to 50 GPa, reverts to its zero-pressure volume on decompression with little hysteresis, and can be fit by a 3rd-order Birch–Murnaghan equation of state. We calculate a bulk modulus ( K 0T ) of 136(4) GPa and a K′ value of 4.6(3). Additionally, we have determined the isothermal Grüneisen parameter for each of the traced Raman modes. These results contribute to growing experimental evidence that suggests some carbonates can be stable at lower mantle conditions. Ultimately, information in this dataset may facilitate predictions of mixing energetics amongst the calcite-structured carbonates, and therefore help determine the role of carbonates in the transition metal geochemistry of the deep Earth.

中文翻译：

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Gaspéite (Ni0.73Mg0.27CO3) 高压行为的 X 射线衍射和拉曼光谱研究

在这里，我们提出了对 50 GPa 的 gaspéite (NiCO 3 ) 的相稳定性和晶格压缩率的新测量。我们的研究是出于我们对理解高压碳酸盐行为的兴趣。虽然碳酸盐在高压和高温条件下已被广泛研究，但它们表现出不同的行为。我们已经使用金刚石砧室、拉曼光谱和 X 射线衍射研究了 gaspéite 的高压行为。我们的实验数据表明，gaspéite 保持方解石结构高达 50 GPa，在减压时恢复到零压力体积，几乎没有滞后，并且可以通过三阶 Birch-Murnaghan 状态方程拟合。我们计算出体积模量 (K 0T ) 为 136(4) GPa，K' 值为 4.6(3)。此外，我们已经确定了每种追踪拉曼模式的等温 Grüneisen 参数。这些结果有助于越来越多的实验证据表明一些碳酸盐在较低的地幔条件下是稳定的。最终，该数据集中的信息可能有助于预测方解石结构碳酸盐之间的混合能量学，因此有助于确定碳酸盐在地球深部过渡金属地球化学中的作用。