Synneusis of Kilauea Iki olivines
Synneusis of Kilauea Iki olivines
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基拉韦厄一奇橄榄石的 Synneusis
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
A. T. Anderson
中科院分区：
文献类型：
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作者：
K. R. Schwindinger;A. T. Anderson
1959年从基拉韦厄伊基喷发出来的苦橄质火山渣中的橄榄石斑晶以2-16个晶体的单斑状集合体出现。橄榄石的成分和三维结构在集合体和单个火山砾中各不相同。来自不同环境的晶体的附着表明，这些聚集体是由合核形成的-晶体一起游泳。大多数晶体都是沿着晶面附着的，它们的a晶轴平行，c晶轴平行或垂直，从而使结构失配和界面能最小化。所观察到的面部附件是一致的流体动力学相互作用的晶体下降与他们的大{010}面水平。聚集体形成于富含液体的岩浆中。粗略的计算表明，最短的聚合时间可能是几分钟。非常小的晶体的聚集表明屈服强度小于3达因cm-2。集合体的结构与堆晶橄榄岩相似。
Olivine phenocrysts in the picritic scoria that erupted from Kilauea Iki in 1959 occur as glomeroporphyritic aggregates of 2–16 crystals. The compositions and three-dimensional textures of the olivines vary within an aggregate and within individual lapilli. The attachment of crystals from different environments indicates that these aggregates formed by synneusis — the swimming together of crystals. Most of the crystals are attached along faces with their a crystallographic axes parallel and their c axes either parallel or perpendicular, so that the structural mismatch and interfacial energy are minimized. Observed facial attachments are consistent with fluid dynamical interactions of crystals falling with their large {010} faces horizontal. The aggregates formed in a liquid-rich magma. Rough computations suggest that the minimum aggregation time could be on the order of minutes. Aggregation of very small crystals suggests that the yield strength was less than 3 dynes cm−2. The textures of the aggregates are similar to those of cumulate peridotites.