HIGH INTERNAL-PRESSURES IN DIAMOND FLUID INCLUSIONS DETERMINED BY INFRARED-ABSORPTION
HIGH INTERNAL-PRESSURES IN DIAMOND FLUID INCLUSIONS DETERMINED BY INFRARED-ABSORPTION
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DOI：
10.1038/353746a0
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发表时间：
1991-10-24
期刊：
影响因子：
64.8
通讯作者：
NAVON, O
中科院分区：
文献类型：
--
作者：
NAVON, O
地幔衍生矿物中的流体包裹体为研究深层地幔流体提供了难得的机会。在地幔矿物中，只有金刚石具有足够的强度来封装和运输被困在 100 公里以下深度的地表流体（参考文献 1）。先前对立方体和涂层钻石中微包裹体的整体成分 2 和内部形态 3 的研究表明它们含有流体，但无法确定它们的起源深度。在此，我报告了红外光谱证据，表明这些微型包裹体内的残余内部压力为 1.5-2.1 GPa，高于之前报道的任何流体包裹体。外推到地幔温度表明流体压力为 4-7 GPa，与根据金刚石 4 中晶体包裹体之间的矿物平衡估计的压力相当。这些压力落在上地幔的金刚石稳定场内，表明富含 H2O、CO2、SiO2 和 K2O 的深层流体可能是立方体钻石和榴辉岩钻石生长的母液。
FLUID inclusions in mantle-derived minerals provide a rare opportunity to study deep-seated mantle fluids. Among mantle minerals, only diamond possesses sufficient strength to encapsulate and transport to the surface fluids that were trapped at depths below 100 km (ref. 1). Previous studies of the bulk composition 2 and internal morphology 3 of micro-inclusions in cubic and coated diamonds suggested that they contain fluids, but their depth of origin could not be determined. Here I report infrared spectroscopic evidence for residual internal pressures of 1.5-2.1 GPa within these micro-inclusions, higher than any reported previously for fluid inclusions. Extrapolation to mantle temperatures indicates fluid pressures of 4-7 GPa, comparable to those estimated on the basis of mineral equilibria between crystalline inclusions in diamond 4. These pressures fall within the diamond stability field in the upper mantle, suggesting that the deep-seated fluids, rich in H2O, CO2, SiO2, and K2O, are probably the mother solutions from which cubic, and possibly eclogitic diamonds grow.