Petrography and olivine and glass chemistry of lavas from the Hawaii Scientific Drilling Project
Petrography and olivine and glass chemistry of lavas from the Hawaii Scientific Drilling Project
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DOI：
10.1029/95jb03846
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发表时间：
1996-05-10
影响因子：
3.9
通讯作者：
Garcia, MO
中科院分区：
文献类型：
--
作者：
Garcia, MO
来自夏威夷科学钻探项目（HSDP）的许多熔岩富含橄榄石（> 10体积%），蚀变较弱。HSDP孔上部的莫纳罗亚火山熔岩更富含橄榄石，通常橄榄石中的镁橄榄石含量高于下面的莫纳克亚火山熔岩。富含橄榄石的熔岩从这些火山包含自形，未变形斑晶和扭结带状捕虏晶的橄榄石，不像是典型的陆上夏威夷拉斑玄武岩假设。这两种橄榄石的镁橄榄石含量范围很广（80 - 90%）。许多HSDP熔岩的橄榄石中含有89 - 90%的镁橄榄石，表明它们生长在至少含有15wt% MgO的岩浆中。这些熔岩中的大多数含有甚至更高的MgO含量（18至28重量%），这是橄榄石斑晶和捕虏晶积累的结果。这些熔岩中的橄榄石捕虏晶被推断为来自变形纯橄榄岩堆晶的解聚，这是存在于许多这些熔岩。一些HSDP流上的帕霍霍结壳的玻璃具有主要元素组成，证实了基于全岩组成的岩心细分。HSDP玻璃的适度演变的组成表明淬火温度与当前基拉韦厄喷发期间测量的温度相似。
Many of the lavas from the Hawaii Scientific Drilling Project (HSDP) are olivine-rich (>10 vol%) and weakly altered. The Mauna Loa lavas from the upper part of the HSDP hole are more olivine-rich and generally have olivines with higher forsterite contents than the underlying Mauna Kea lavas. Olivine-rich lavas from these volcanoes contain both euhedral, undeformed phenocrysts and kink-banded xenocrysts of olivines, unlike what was assumed for typical subaerial Hawaiian tholeiites. The forsterite content of both ty;pes of olivine ranges widely (80-90%). Many of the HSDP lavas have olivines with forsterite contents of 89-90%, indicating that they grew in magmas with at least 15 wt % MgO. Most of these lavas contain even higher MgO contents (18 to 28 wt %), which are a result of accumulation of olivine phenocrysts and xenocrysts. The olivine xenocrysts in these lavas are inferred to be derived from disaggregation of deformed dunite cumulates, which are present in many of these lavas. Glasses from pahoehoe crusts on some of the HSDP flows have major element compositions that confirm the subdivision of the core based on whole rock compositions. The moderately evolved compositions of the HSDP glasses indicate quenching temperatures similar to those measured during the current Kilauea eruption.