...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Contributions to Mineralogy and Petrology >Clinopyroxene/Uquid trace element partitioning In natural trachyte-trachyphonollte systems: insights from Campi Flegrel (southern Italy)
【24h】

Clinopyroxene/Uquid trace element partitioning In natural trachyte-trachyphonollte systems: insights from Campi Flegrel (southern Italy)

机译：Clinopyroxene / Uquid微量元素在天然曲霉菌-曲霉菌系统中的分配：来自Campi Flegrel（意大利南部）的见解

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Trace element partition coefficients between clinopyroxenes and associated glassy matrix (~(Cpx/L) have been determined for 13 REE, HFSE~(4+,5+), U, Th, Sr, Pb, Sc and V from combined LA-ICP-MS/EMP analyses in selected trachytes and trachyphonolites from Campi Flegrei, Composition of clinopyroxene and glass is pretty homogeneous in the trachyphonolites, pointing to an overall attainment of the equilibrium conditions. In trachytes, conversely, phases show some compositional heterogeneity (due to the presence of clinopyroxene xenocrysts) that requested a more careful petrographic and geochemical inspection of the samples to assess the equilibrium clinopyroxene composition. In the trachyte clinopyroxenes, REE are compatible from Nd to Lu (~(Cpx/L)D up to 2.9), like Y, Ti, Sc and V. The~(Cpx/L)D for Eu is lower than those of the adjacent REE, highlighting Eu~(2+) contribution. High D values are also shown by U, Th, Pb, Zr, Hf, Nb and Ta relatively to basaltic and andesitic systems, whereas the D_(Sr) is roughly similar to that found for less evolved magmas. Trachyphonolites are characterized by an overall decrease of the ~(Cpx/L)D for highly-charged cations (with the exception of V), and by a slight increase of D_(Sr). REE are still compatible from Nd to Lu (~(Cpx/L)D up to 2.1), like Ti, Y, Sc and V. This variation is also predicted for REE and Y by models based on the elastic strain theory, being consistent with the slightly lower polymerization degree estimated for the trachyphonolites. However, the observed ~(Cpx/L)D(REE,Y) are matched by the modelled ones only considering very low T (<825 deg C), which are believed unlikely. This mismatch cannot be attributed to effects induced by the water-rich composition of the trachyte-trachyphonolite suite, since they would lower the observed ~(Cpx/L)D_(REE,Y). Moreover, the anomalous inflections of measured ~(Cpx/L)D for HREE suggests some crystal-chemical control, such as the entrance of these elements in a site distinct from M2. It is concluded that the large ~(Cpx/L)D determined for trachytes and trachyphonolites are likely induced by hitherto unconstrained changes of the Z~(3+) activities related to the composition of melt and/or solid. All these considerations strongly highlight the importance of a direct characterization of trace element partitioning in natural samples from magmatic systems poorly characterized by experimental studies.
机译：通过组合的LA-ICP确定了13种稀土元素，HFSE〜（4 +，5 +），U，Th，Sr，Pb，Sc和V的斜茂铁与相关玻璃状基质（〜（Cpx / L）之间的痕量元素分配系数对来自Campi Flegrei的选定的曲子和曲子中的-MS / EMP分析表明，曲子中斜辉石和玻璃的成分相当均匀，表明总体上达到了平衡条件。相反，在曲子中，相显示出某些成分异质性（由于斜辉石异种晶的存在要求对样品进行更精细的岩石学和地球化学检查，以评估斜辉石的平衡组成。在曲奇斜辉石中，REE从Nd到Lu（〜（Cpx / L）D最高为2.9）相容。 Eu的〜（Cpx / L）D低于相邻的REE，突出了Eu〜（2+）的贡献，高的D值也由U，Th，Pb，Zr表示，Hf，Nb和Ta相对于玄武岩和安山岩体系，而D_（Sr）与演化较少的岩浆大致相似。菱铁矿的特征是高电荷阳离子（V除外）的〜（Cpx / L）D总体降低，D_（Sr）略有增加。 REE从Nd到Lu（〜（Cpx / L）D直到2.1）仍然兼容，例如Ti，Y，Sc和V。通过弹性应变理论基于模型的REE和Y也可以预测这种变化，这是一致的据估计，亚风沸石的聚合度略低。但是，仅考虑到非常低的T（<825摄氏度），所观察到的〜（Cpx / L）D（REE，Y）就可以与建模模型匹配，这被认为是不可能的。这种失配不能归因于曲奇-次长晶石套件的富水成分引起的效应，因为它们会降低观察到的〜（Cpx / L）D_（REE，Y）。此外，对HREE测得的〜（Cpx / L）D的异常拐点表明了某些晶体化学控制，例如这些元素进入不同于M2的位置。得出的结论是，迄今对熔体和/或固体组成相关的Z〜（3+）活性的无限制变化可能导致了对曲奇和曲奇石的较大〜（Cpx / L）D的诱导。所有这些考虑都强烈突出了直接表征来自岩浆系统的天然样品中痕量元素分配的特征的重要性，而天然岩浆系统的实验研究较差。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号