Partitioning of Hf, Lu, Ti, and Mn between olivine, clinopyroxene and basaltic liquid
Partitioning of Hf, Lu, Ti, and Mn between olivine, clinopyroxene and basaltic liquid
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Hf、Lu、Ti 和 Mn 在橄榄石、单斜辉石和玄武岩液体之间的分配
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发表时间：
1987
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通讯作者：
T. Dunn
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文献类型：
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作者：
T. Dunn
本文测定了Lu、Hf、Ti、Mn和Ca在橄榄石、单斜辉石和玄武岩熔体之间的晶体/液体分配系数。Ti，Mn和Ca的分配系数测定在自然丰度水平。Lu和Hf分配系数在掺杂水平范围为0.5至1.5wt%的“痕量元素”作为氧化物时测定，以允许通过电子微探针进行分析。在1 bar和1150至1177° C的温度下测定Lu、Hf、Ti、Mn和Ca的橄榄石/液体分配系数。在10、15和20 kbar的压力和1250至1290° C的温度下测定Lu、Hf、Ti和Mn的单斜辉石/液体分配系数。Hf、Lu、Ti和Ca的橄榄石/液体分配系数很小。D（Hf-ol）在分析不确定度范围内为零。D（Lu-ol）和D（Mn-ol）均随温度的升高而降低，而D（Ti-ol）和D（Ca-ol）在所研究的较窄温度范围内保持不变。分配系数结果总结如下：T° C115011671177 D（Lu-ol）0.081±0.0270.065±0.0340.045± 0.009 D（Ti-ol）0.017±0.0040.018±0.0060.015± 0.006 D（Ca-ol）0.035±0.0020.034 ± 0.0030.034 ± 0.003 D（Mn-ol）1.53±0.061.42±0.081.38±0.04
Lu和Hf的单斜辉石/液体分配系数相当大。D（Hf-cpx）和D（Lu-cpx）均随温度和压力的升高而减小。在分析不确定度范围内，D（Ti-cpx）和D（Mn-cpx）与温度和压力无关。单斜辉石/液体分配系数为：T° C1250126512751290 P（千巴）10151520 D（Hf-cpx）0.035±0.020.30±0.020.33±0.070.26±0.02D（Lu-cpx）0.61±0.040.55±0.070.57±0.040.50±0.05D（Ti-cpx）0.42±0.040.35±0.050.43±0.070.40±0.06D（Mn-cpx）0.85±.0.130.91 ± 0.140.88±0.130.81±0.21
利用本研究中确定的分配系数和文献中的数据进行的部分熔融计算表明，玄武质熔岩中176 Hf/177 Hf的观测变化可以用仅包含主要相（ol，opx，cpx）的简单地幔的小程度部分熔融来解释。
AbstractThe crystal/liquid partition coefficients of Lu, Hf, Ti, Mn and Ca have been measured between olivine, clinopyroxene and basaltic melt. The Ti, Mn, and Ca partition coefficients were determined at natural abundance levels. The Lu and Hf partition coefficients were determined at doping levels ranging from 0.5 to 1.5 wt% “trace element” as oxide in order to allow analysis by electron microprobe. Olivine/liquid partition coefficients for Lu, Hf, Ti, Mn, and Ca were determined at 1 bar and temperatures from 1150 to 1177° C. Clinopyroxene/liquid partition coefficients were determined for Lu, Hf, Ti, and Mn at pressures of 10, 15, and 20 kbars and temperatures from 1250 to 1290° C.The olivine/liquid partition coefficients of Hf, Lu, Ti, and Ca are small. D(Hf-ol) is zero within the analytical uncertainty. Both D(Lu-ol) and D(Mn-ol) decrease with increasing temperature, but D(Ti-ol) and D(Ca-ol) are constant over the narrow temperature range studied. The partition coefficient results are summarized below.T°C115011671177D(Lu-ol)0.081±0.0270.065±0.0340.045±0.009D(Ti-ol)0.017±0.0040.018±0.0060.015±0.006D(Ca-ol)0.035±0.0020.034±0.0030.034±0.003D(Mn-ol)1.53±0.061.42±0.081.38±0.04
The clinopyroxene/liquid partition coefficients for Lu and Hf are considerably larger. D(Hf-cpx) and D(Lu-cpx) both decrease with increasing temperature and pressure. D(Ti-cpx) and D(Mn-cpx) are independent of temperature and pressure within the analytical uncertainty. The clinopyroxene/liquid distribution coefficients are:T°C1250126512751290P(kbar)10151520D(Hf-cpx)0.035±0.020.30±0.020.33±0.070.26±0.02D(Lu-cpx)0.61±0.040.55±0.070.57±0.040.50±0.05D(Ti-cpx)0.42±0.040.35±0.050.43±0.070.40±0.06D(Mn-cpx)0.85±.0.130.91±0.140.88±0.130.81±0.21
Fractional melting calculations, using the distribution coefficients determined in this study and data from the literature, show that the observed variation in176Hf/177Hf in basaltic lavas can be explained by small degrees of partial melting of a simple mantle containing only major phases (ol, opx, cpx).