GEOTHERMOBAROMETRY IN 4-PHASE LHERZOLITES .2. NEW THERMOBAROMETERS, AND PRACTICAL ASSESSMENT OF EXISTING THERMOBAROMETERS
GEOTHERMOBAROMETRY IN 4-PHASE LHERZOLITES .2. NEW THERMOBAROMETERS, AND PRACTICAL ASSESSMENT OF EXISTING THERMOBAROMETERS
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DOI：
10.1093/petrology/31.6.1353
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发表时间：
1990-12-01
影响因子：
3.9
通讯作者：
KOHLER, T
中科院分区：
文献类型：
--
作者：
BREY, GP;KOHLER, T
在本系列第一部分实验的基础上，对大多数已发表的与四相橄榄岩有关的温压计进行了实验条件再现能力的测试。 如果在压力或温度方面有任何系统性的差异，它们就会被拒绝。 本试验警告不要使用基于共存的斜方辉石和单斜辉石组成的所有已公布版本的温度计，也不要使用基于与石榴石共存的斜方辉石的Al含量的现有气压计。 因此，我们制定了两个辉石温度计和铝在opx barmeter的新版本：[GRAPHICS]与K（D）* =（1-Ca*）cpx/（1-Ca*）opx，Ca* = CaM 2/（1-Na（M2））和X（Fe）px = Fe/（Fe + Mg）; T（BKN）是开氏度和P是在m2。我们的新的barmeter是[GRAPHICS]（C1-C3）的形式和位置占有率在文本中给出。温度也可以计算从单独的钙含量opx：[图形]该温度计可用于CMS和自然系统实验，这可能表明Fe和Na具有反作用，Na在opx和cpx之间的分配也可以用作有用的温度计，并且从天然岩石数据校准：其中T是开氏度，P是分子量，D（Na）= Na（opx）/Na（cpx）。以下三种公开的基于进一步交换反应的温压计能够再现实验条件：（a）橄榄石和单斜辉石之间的Ca交换作为气压计（P（KB）），（B）石榴石和单斜辉石之间的Fe和Mg交换作为温度计（T（Krogh）），（c）石榴子石和橄榄石之间的Fe和Mg交换作用，作为温度计（T（奥尼尔））。
On the basis of experiments presented in Part I of this series, most of the published thermobarometers relevant to four-phase peridotites are tested here for their ability to reproduce experimental conditions. They were rejected if any systematic discrepancy in either pressure or temperature was discernible. This test cautions against the use of all published versions of thermometers based on the compositions of coexisting ortho- and clinopyroxenes and the use of existing barometers based on the Al content of orthopyroxene coexisting with garnet. Therefore, we formulated new versions of the two-pyroxene thermometer and the Al-in-opx barmometer:[GRAPHICS]with K(D)* = (1-Ca*)cpx/(1-Ca*)opx, Ca* = CaM2/(1-Na(M2)) and X(Fe)px = Fe/(Fe + Mg); T(BKN) is in degrees Kelvin and P is in kilobars.Our new barometer is of the form[GRAPHICS](C1-C3) and site occupancies are given in the text.Temperatures may also be calculated from the Ca content of opx alone:[GRAPHICS]This thermometer can be applied both to the CMS and the natural system experiments, which may indicate that Fe and Na have counter-balancing effects on the Ca content of opx.The partitioning of Na between opx and cpx can also serve as a useful thermometer, and was calibrated from natural rock data:[GRAPHICS]where T is in degrees Kelvin, P is in kilobars, and D(Na) = Na(opx)/Na(cpx).The following three published thermobarometers based on further exchange reactions are capable of reproducing experimental conditions: (a) exchange of Ca between olivine and clinopyroxene as a barometer (P(KB)), (b) exchange of Fe and Mg between garnet and clinopyroxene as a thermometer (T(Krogh)), (c) exchange of Fe and Mg between garnet and olivine as a thermometer (T(O'Neill)).