...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Evolution of young andesitic-dacitic magmatic systems beneath Dominica, Lesser Antilles
【24h】

Evolution of young andesitic-dacitic magmatic systems beneath Dominica, Lesser Antilles

机译：小安地列斯群岛多米尼加以下的年轻安第斯-胶体-岩浆岩浆系统的演化

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

The geology of Dominica, Lesser Antilles, is dominated by young (<200 ka) andesitic-dacitic volcanic deposits. Although previous studies have mostly focused on the Plat Pays Volcanic Centre (PPVC), a volcanic complex located on the south-western tip of Dominica, evolved deposits are found across the entire island. Dominica's andesitic-dacitic volcanic rocks are characterized by wide ranges in mineral compositions and a host of disequilibrium features. Mineral-mineral and mineral-melt equilibrium constraints suggest that three separate equilibrium assemblages are associated with the development of these evolved magmas. While Rayleigh fractionation modeling indicates that these equilibrium groups may be related via fractional crystallization, enclaves with irregular boundaries and chilled margins provide evidence of open-system processes such as magma mingling. To explain the disequilibrium assemblages and textures, we propose that Dominica andesites and dacites are the result of convective self-mixing within magma reservoirs comprised of three distinct components: 1) underplating basalt, 2) basaltic-andesitic mush and 3) interstitial rhyolitic melt. A notable exception is Aux Diables, the northernmost center on the island, which has a strikingly different whole-rock geochemistry than other centers. Trace element modeling indicates that this center is influenced by lower crustal assimilation in addition to fractional crystallization. This study suggests that basaltic-andesitic mush is a necessary component in the generation of evolved magmas beneath the island of Dominica. Available ages suggest that such mush has existed beneath parts of the island for at least 200 ka. (C) 2015 Elsevier B.V. All rights reserved.
机译：多米尼加的小安的列斯群岛的地质主要是年轻的（<200 ka）安第斯-达特奇火山岩沉积。尽管先前的研究主要集中在位于多米尼加西南端的Plat Pays火山中心（PPVC），这是一个火山综合体，但在整个岛屿上都发现了沉积物。多米尼加的安第斯-达特奇时代的火山岩的特征是矿物成分范围广泛，并具有许多不平衡特征。矿物-矿物和矿物-熔体的平衡约束表明，三个独立的平衡组合与这些演化岩浆的发育有关。尽管瑞利分馏模型表明这些平衡基团可能通过分步结晶而相关，但具有不规则边界和冷边界的飞地提供了岩浆混合等开放系统过程的证据。为了解释不平衡的组合和质地，我们认为多米尼加安山岩和dacites是在岩浆储层内对流自混合的结果，其由三个截然不同的成分组成：1）玄武岩底层，2）玄武岩-安山岩糊状岩和3）间隙流纹岩熔体。一个值得注意的例外是岛上最北端的中心奥克斯迪布尔斯（Aux Diables），它的全岩石地球化学特征与其他中心截然不同。痕量元素建模表明，除了部分结晶作用外，该中心还受到下地壳同化的影响。这项研究表明，玄武岩糊剂是在多米尼加岛下方形成岩浆形成的必要组成部分。现有年龄表明，这种糊状食物在岛上至少存在200 ka。 （C）2015 Elsevier B.V.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 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