Trace element abundances of high-MgO glasses from Kilauea, Mauna Loa and Haleakala volcanoes, Hawaii
Trace element abundances of high-MgO glasses from Kilauea, Mauna Loa and Haleakala volcanoes, Hawaii
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夏威夷基拉韦厄火山、莫纳罗亚火山和哈雷阿卡拉火山的高 MgO 玻璃的微量元素丰度
DOI：
10.1007/s004100050375
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发表时间：
1998
影响因子：
3.5
通讯作者：
T. Grove
中科院分区：
文献类型：
--
作者：
T. Wagner;D. Clague;E. Hauri;T. Grove
摘要我们对来自夏威夷基拉韦厄火山、莫纳罗亚火山和哈雷卡拉火山的11个高镁(6.7-14.8wt%)拉斑玄武岩玻璃进行了离子探针研究。我们测定了这些玻璃的稀土(RE)、高场强和其他选定的微量元素丰度，并利用这些数据建立了它们与典型的夏威夷盾拉斑玄武岩的关系，并推断了它们的来源特征。该玻璃具有与L(轻)REE/H(重)REEC1 <； 1等典型屏蔽拉斑玄武岩基本相似的微量元素丰度特征。然而，基拉韦厄和毛纳罗亚玻璃显示出与基拉韦厄和毛纳罗亚屏蔽熔岩之间存在交叉的痕量和常量元素特征。这些玻璃含有这些区别化学特征的混合物，与两座火山的典型盾状熔岩并不完全相同。这些混合岩浆的产生可能需要一个复杂的地带性来源，而不是两个独特的来源。经橄榄石分馏校正后，玻璃数据显示了CaO浓度与不相容微量元素丰度之间的相关性，表明CaO在拉斑玄武岩源区熔融过程中可能表现出不相容的行为。此外，拉斑玄武岩的来源必须含有残留的石榴石和单斜辉石，以解释基拉韦厄玻璃中微量元素丰度的变化。反演模拟表明，基拉韦厄源区相对于C_1球粒陨石是平坦的，重稀土元素的体积分配系数高于轻稀土元素。
Abstract We performed an ion-microprobe study of eleven high-MgO (6.7–14.8 wt%) tholeiite glasses from the Hawaiian volcanoes Kilauea, Mauna Loa and Haleakala. We determined the rare earth (RE), high field strength, and other selected trace element abundances of these glasses, and used the data to establish their relationship to typical Hawaiian shield tholeiite and to infer characteristics of their source. The glasses have trace element abundance characteristics generally similar to those of typical shield tholeiites, e.g. L(light)REE/H(heavy)REEC1 < 1. The Kilauea and Mauna Loa glasses, however, display trace and major element characteristics that cross geochemical discriminants observed between Kilauea and Mauna Loa shield lavas. The glasses contain a blend of these discriminating chemical characteristics, and are not exactly like the typical shield lavas from either volcano. The production of these hybrid magmas likely requires a complexly zoned source, rather than two unique sources. When corrected for olivine fractionation, the glass data show correlations between CaO concentration and incompatible trace element abundances, indicating that CaO may behave incompatibly during melting of the tholeiite source. Furthermore, the tholeiite source must contain residual garnet and clinopyroxene to account for the variation in trace element abundances of the Kilauea glasses. Inversion modeling indicates that the Kilauea source is flat relative to C1 chondrites, and has a higher bulk distribution coefficient for the HREE than the LREE.