Petrology, geochemistry, and ages of lavas from Northwest Hawaiian Ridge volcanoes
Petrology, geochemistry, and ages of lavas from Northwest Hawaiian Ridge volcanoes
复制标题
西北夏威夷岭火山熔岩的岩石学、地球化学和年龄
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
B. Jicha
中科院分区：
文献类型：
--
作者：
Michael O. Garcia;J. R. Smith;J. Tree;D. Weis;L. Harrison;B. Jicha
西北夏威夷山脊是大型火成岩省的典型例子。尽管构成了夏威夷-皇帝链最长的一段（约 47%），但该山脊的形态和地质特征尚不清楚。在这里，我们提出了西北夏威夷山脊 12 座火山熔岩的新测深汇编、岩相学和 X 射线荧光 (XRF) 数据，并回顾了山脊年龄和同位素变化的文献数据。测深汇编显示，西北夏威夷海脊至少由 51 座火山组成。 45 个新的 XRF 分析表明，西北夏威夷海脊含有拉斑斑玄武岩和碱性熔岩，其成分具有夏威夷群岛熔岩的典型成分。西北夏威夷山脊各个火山的绝对年龄和火山活动持续时间鲜为人知，只有 10 座火山的现代 40Ar/39Ar 年龄，大部分位于火山链的弯曲处。我们推断夏威夷皇帝弯的起始年龄约为 1000 年。 49~48Ma，比西太平洋岛弧火山活动爆发的年龄（52~51Ma）要早。因此，夏威夷-皇帝链的扭结和弧火山活动的爆发并不同步。西北夏威夷海脊的同位素数据很少，尤其是 Pb 和 Hf 的同位素数据。弯道以南的两处过渡熔岩具有 Loa 趋势类型的 Pb 和 Sr 同位素比。另外，西北夏威夷山脊熔岩的可用化学成分表明了啄木鸟趋势的来源成分。夏威夷海脊沿线熔体通量的急剧增加（~300%）可能与熔化条件、源肥力或板块应力的变化有关。 1 Garcia, M.O.、Smith, J.R.、Tree, J.P.、Weis, D.、Harrison, L. 和 Jicha, B.R.，2015 年，西北夏威夷山脊火山熔岩的岩石学、地球化学和年龄，载于 Neal, C.R.、Sager, W.W.、Sano, T. 和 Erba, E. 编辑，起源、演化和海洋大型火成岩省的环境影响：美国地质学会特别论文 511，第 14 页。 1–25，doi：10 .1130 /2015 .2511 (01)。如需复制许可，请联系editing@geosociety.org。 © 2015 美国地质学会。版权所有。于 2015 年 6 月 17 日specialpapers.gsapubs.org 下载自
The Northwest Hawaiian Ridge is a classic example of a large igneous province. The morphology and geology of the ridge is poorly characterized, although it constitutes the longest segment (~47%) of the Hawaiian-Emperor Chain. Here we present a new bathymetric compilation, petrographic and X-ray fl uorescence (XRF) data for lavas from 12 volcanoes along the Northwest Hawaiian Ridge, and review literature data for the age and isotopic variation of the ridge. The bathymetric compilation revealed that the Northwest Hawaiian Ridge consists of at least 51 volcanoes. The 45 new XRF analyses show that the Northwest Hawaiian Ridge contains tholeiitic and alkalic lavas with compositions typical of lavas from the Hawaiian Islands. The absolute ages and duration of volcanism of individual Northwest Hawaiian Ridge volcanoes are poorly known, with modern 40Ar/39Ar ages for only 10 volcanoes, mostly near the bend in the chain. We infer the initiation age of the Hawaiian-Emperor Bend to be ca. 49–48 Ma, younger than the age for the onset of island arc volcanism in the western Pacifi c (52–51 Ma). Thus, the kink in the Hawaiian-Emperor Chain and the onset of arc volcanism were not synchronous. Isotopic data are sparse for the Northwest Hawaiian Ridge, especially for Pb and Hf. Two transitional lavas from just south of the bend have Loa trend type Pb and Sr isotopic ratios. Otherwise, the available chemistry for Northwest Hawaiian Ridge lavas indicates Kea-trend source compositions. The dramatic increase in melt fl ux along the Hawaiian Ridge (~300%) may be related to changes in melting conditions, source fertility, or plate stresses. 1 Garcia, M.O., Smith, J.R., Tree, J.P., Weis, D., Harrison, L., and Jicha, B.R., 2015, Petrology, geochemistry, and ages of lavas from Northwest Hawaiian Ridge volcanoes, in Neal, C.R., Sager, W.W., Sano, T., and Erba, E., eds., The Origin, Evolution, and Environmental Impact of Oceanic Large Igneous Provinces: Geological Society of America Special Paper 511, p. 1–25, doi: 10 .1130 /2015 .2511 (01). For permission to copy, contact editing@geosociety.org. © 2015 The Geological Society of America. All rights reserved. on June 17, 2015 specialpapers.gsapubs.org Downloaded from