Phase relations of CaCO3 at high pressure and high temperature
Phase relations of CaCO3 at high pressure and high temperature
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DOI：
10.2138/am-2001-8-906
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发表时间：
2001-09
影响因子：
3.1
通讯作者：
K. Suito;Junpei Namba;T. Horikawa;Y. Taniguchi;N. Sakurai;M. Kobayashi;A. Onodera;O. Shimomura
中科院分区：
文献类型：
--
作者：
K. Suito;Junpei Namba;T. Horikawa;Y. Taniguchi;N. Sakurai;M. Kobayashi;A. Onodera;O. Shimomura
摘要：方解石是CaCO3的一种天然晶体形式，本文采用三种不同的实验技术研究了方解石的相变：(1)在立方顶压机中使用同步辐射到6 GPa和1750°C的原位x射线衍射（XRD）；(2)室温下金刚石砧细胞拉曼散射至10 GPa；(3)在八面体顶压机中，温度至2000℃，压力至9 GPa热处理后样品的压缩后XRD。在室温下，方解石I在1.7 GPa下转变为方解石II，然后在~2 GPa下转变为方解石III。方解石III持续到至少10 GPa。在3、4、6 GPa温度的升高引起了一系列的转变：方解石III→文石→无序方解石→液体，在液体快速冷却后文石被保留。无序方解石的熔化曲线随压力的增大遵循如下关系式：Tm（℃）= 1338 + 82 P - 2.9 P2 （P单位为GPa）。
Abstract Phase transitions in calcite, a naturally occurring crystalline form of CaCO3, have been investigated by three different experimental techniques: (1) in-situ X-ray diffraction (XRD) using synchrotron radiation to 6 GPa and 1750 °C in a cubic anvil press; (2) Raman scattering to 10 GPa at room temperature using a diamond-anvil cell; and (3) post-compression XRD on samples retrieved after heat treatment at temperatures to 2000 °C and pressures to 9 GPa in an octahedral anvil press. At room temperature, calcite I transformed into calcite II at 1.7 GPa and then to calcite III at ~2 GPa. Calcite III persisted to at least 10 GPa. Elevation of temperature at 3, 4, and 6 GPa caused a sequence of transitions: calcite III → aragonite → disordered calcite → liquid, and aragonite was retained upon rapid cooling of the liquid. The melting curve of disordered calcite increased with pressure following a relation: Tm (°C) = 1338 + 82 P - 2.9 P2 where P is in units of GPa.