An internally consistent pressure calibration of geobarometers applicable to the Earth's upper mantle using in situ XRD
An internally consistent pressure calibration of geobarometers applicable to the Earth's upper mantle using in situ XRD
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DOI：
10.1016/j.gca.2017.10.031
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发表时间：
2018-02
影响因子：
5
通讯作者：
C. Beyer;A. Rosenthal;R. Myhill;W. Crichton;Tony Yu;Yanbin Wang;D. Frost
中科院分区：
文献类型：
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作者：
C. Beyer;A. Rosenthal;R. Myhill;W. Crichton;Tony Yu;Yanbin Wang;D. Frost
我们已经进行了实验交叉校准的一套矿物平衡内地幔岩石的整体组成，通常用于地质测压，以确定上地幔组合的平衡深度。在实验运行中同时比较了多个气压计，其中使用MgO、NaCl、Re和h-BN的晶胞体积在3.6和10.4 GPa以及1250和1500 °C之间的原位测量来确定压力。实验在大体积压机（LVP）中结合同步加速器X射线衍射进行。用多个样品室钻取的贵金属胶囊装载有一系列代表橄榄岩、榴辉岩和辉石岩岩性的散装组合物。通过这种方法，我们同时校准的地质压力计适用于不同的地幔岩性在相同的和确定的压力和温度条件。我们确定了计算和实验压力之间的差异，我们提出了简单的线性或恒定的修正系数，以前公布的一些气压方程。因此，我们建立了内部一致的交叉校准的一些石榴石斜方辉石，石榴石单斜辉石，钙Tschermaks-在单斜辉石和majorge地质压力计。
We have performed an experimental cross calibration of a suite of mineral equilibria within mantle rock bulk compositions that are commonly used in geobarometry to determine the equilibration depths of upper mantle assemblages. Multiple barometers were compared simultaneously in experimental runs, where the pressure was determined usingin-situmeasurements of the unit cell volumes of MgO, NaCl, Re and h-BN between 3.6 and 10.4 GPa, and 1250 and 1500 °C. The experiments were performed in a large volume press (LVPs) in combination with synchrotron X-ray diffraction. Noble metal capsules drilled with multiple sample chambers were loaded with a range of bulk compositions representative of peridotite, eclogite and pyroxenite lithologies. By this approach, we simultaneously calibrated the geobarometers applicable to different mantle lithologies under identical and well determined pressure and temperature conditions. We identified discrepancies between the calculated and experimental pressures for which we propose simple linear or constant correction factors to some of the previously published barometric equations. As a result, we establish internally-consistent cross-calibrations for a number of garnet-orthopyroxene, garnet-clinopyroxene, Ca-Tschermaks-in-clinopyroxene and majorite geobarometers.