• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Geochemical heterogeneity within mid-ocean ridge lava flows: insights into eruption, emplacement and global variations in magma generation
【24h】

Geochemical heterogeneity within mid-ocean ridge lava flows: insights into eruption, emplacement and global variations in magma generation

机译：中洋洋脊熔岩流中的地球化学异质性：对岩浆生成中喷发，沉积和全球变化的见解

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

Compositional heterogeneity in mid-ocean ridge (MOR) lava flows is a powerful yet presently under-utilized volcanological and petrological tracer. Here, it is demonstrated that variations in pre- and syn-eruptive magmatic conditions throughout the global ridge system can be constrained with intra-flow compositional heterogeneity among 10 discrete MOR flows. Geographical distribution of chemical heterogeneity within flows is also used along with mapped physical features to help decipher the range of conditions that apply to seafloor eruptions (i.e. inferred vent locations and whether there were single or multiple eruptive episodes). Although low-pressure equilibrium fractional crystallization can account for much of the observed intra-flow compositional heterogeneity, some cases require multiple parent magmas and/or more complex crystallization conditions. Globally, the extent of within-flow compositional heterogeneity is well correlated (positively) with estimated erupted volume for flows from the northern East Pacific Rise (EPR), and the Mid Atlantic Juan de Fuca and Gorda Ridges; however, some lavas from the superfast spreading southern EPR fall below this trend. Compositional heterogeneity is also inversely correlated with spreading rate. The more homogeneous compositions of lavas from faster spreading ridges likely reflect the relative thermal stability and longevity of sub-ridge crustal magma bodies, and possibly higher eruption frequencies. By contrast, greater compositional heterogeneity in lavas at slower spreading rates probably results from low thermal stability of the crust (due to diminished magma supply and greater hydrothermal cooling). Finally, the within-flow compositional variations observed here imply that caution must be exercised when interpreting MOR basalt data on samples where individual flows have not been mapped because chemical variations between lava samples may not necessarily record history of spatially and temporally distinct eruptions.
机译：大洋中脊（MOR）熔岩流中的成分异质性是一种功能强大但目前未得到充分利用的火山和岩石示踪剂。在这里，已证明，在整个全球脊系统中，火山前和协同火山岩条件的变化可以用10个离散MOR流中的流内成分异质性来约束。流中化学异质性的地理分布也与映射的物理特征一起使用，以帮助破译适用于海底喷发的条件范围（即推测的喷口位置以及是否有单发或多发喷发）。尽管低压平衡分步结晶可解决大部分观测到的流内成分非均质性问题，但某些情况下需要多个母岩浆和/或更复杂的结晶条件。在全球范围内，流内成分的异质性程度与（东）北部太平洋上升带（EPR），大西洋中部胡安·德富卡和戈达山脊的估计喷发量有很好的相关性（呈正相关）。但是，来自南部EPR的超快扩散的一些熔岩低于这一趋势。成分异质性也与扩散速率成反比。来自较快散布的山脊的熔岩成分更加均匀，可能反映了亚山脊地壳岩浆体的相对热稳定性和寿命，以及可能更高的喷发频率。相比之下，熔岩在较低的扩散速率下更大的成分非均质性可能是由于地壳的热稳定性低（由于岩浆供应减少和更大的水热冷却作用）。最后，此处观察到的流内成分变化意味着，在解释未绘制单个流的样品的MOR玄武岩数据时，必须谨慎行事，因为熔岩样品之间的化学变化不一定记录时空不同的喷发历史。

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