中文摘要：

碳酸盐矿物在地幔温压条件下的稳定性和结构变化对理解地球内部碳的存在形式、建立深部碳循环模型具有重要的指示意义。本文利用金刚石对顶砧装置,借助同步辐射X射线衍射和拉曼光谱技术,对天然菱锰矿单晶的结构稳定性和弹性性质进行了研究。结果表明：菱锰矿在压力达到-10 GPa时结构保持不变,但c轴方向的压缩性大于a轴。菱猛矿的等温状态方程参数为V0=308.8（2）-3、K0=104（1）GPa和K＇0=4（fixed）。[CO3]2-基团对称伸缩振动（ν1）和平面内振动（ν2）引起的拉曼峰分别位于1 087.9 cm-1和720.5 cm-1,基团外振动峰（ν3）出现在293.8cm-1,三者的拉曼位移均与压力呈良好的线性正相关关系,且外振动对压力的响应比内振动敏感。计算得到内振动的模式Grüneisen参数γ（ν1）=-0.29和γ（ν2）=-0.26,远小于外振动γ（ν3）=-1.57。进一步证明菱锰矿的压缩取决于[MnO6]体积的减小而非[CO3]2-基团的压缩。结合前人的研究结果,本文对方解石型碳酸盐的弹性性质及其变化规律进行了总结。

英文摘要：

Investigation of the structural stability and modification of carbonates under mantle conditions contribute to understanding the Earth＇s carbon cycle. In the present work, synchrotron radiation X-ray diffraction and Raman spectroscopy were employed to investigate the structural stability and elastic properties of single-crystal rhodochrosite in diamond anvil cell device. The results demonstrate that rhodochrosite maintains stable up to 10 GPa and exhibits anisotropy with c-axis being more compressible than a-axis. Isothermal equation of state parameters of rhodochrosite was obtained as V0 = 308.8（2） A3, K0 = 104（1） GPa and K0 = 4（fixed）. The symmetrical stretching band （v1 ） and in-plane vibration band （v2） of [CO3 ]2- were observed at 1 087.9 cm-1 and 720.5 cm- 1, respectively, and the external （v3） at 293.8 cm- 1, all of which present linear positive relationships with pressure, and the external mode is more sensitive to compression. Mode Gruneisen parameters of internal mode （y v1 = -0.29 and y v2 = -0.26） are lower than that of the external mode （y v3 = -1.57）, indi- cating that the bulk compression is largely due to the contraction of [ MnO6 ] rather than that of [ CO3 ]2 . Elastic properties of calcite-type carbonates are discussed in consideration of previous reports.