Testing for the Pulse of the Iceland Plume: IODP EXP.395

地幔柱有脉搏吗？板内火山活动是否波动，是否由地球内部深处的地幔动力学决定？这些变化如何影响地球的居住表面，气候和生命支持系统？这些是我们在IODP Exp中要解决的一些问题。395.海洋岛屿和高原提供了强有力的证据，表明物质和能量的大量流动是通过独立于正常板块构造周期的过程从地球内部转移到其表面的。今天，大洋中脊占地幔质量和能量通量的95%，而在过去，热点火山活动的贡献高达50%。这种岩浆活动的脉冲在气候变化、质量变化、地磁场异常和海底扩张速度加快、热液活动和大陆分裂中得以实现。然而，这些过度火山活动的脉冲在一系列时间尺度上都是断断续续的。如果我们要深入了解地幔动力学和地球演化，了解它们的周期性和过程是必不可少的。在这个提议中，我们的目标是测试对冰岛高原形成负责的热点的起源和影响的假设。通过它与邻近的缓慢扩张的雷克珍海脊的相互作用，我们的目标是恢复过去35 Ma冰岛热点火山活动及其变化的记录。具体来说，IODP Exp.395将调查热点地幔是否在冰岛下方上升，并沿沿着洋脊横向平流。冰岛热点的熔体生产波动是由一套嵌套的穿时V形脊，形成雷克雅内斯脊的侧翼。通过在这些V形脊上取样，我们将探索它们是否是由热点地幔通量、温度或成分的波动引起的。此外，我们将研究洋壳的化学老化，因为它受到邻近热点的影响。冰岛-雷克雅未克海脊对的研究被广泛认为是热点-海脊相互作用的典型例子。这项研究的结果将是更好地了解地幔热点动力学及其对海洋盆地演化、周围陆块、气候和海洋环流的影响。

Do mantle plumes have a pulse? Does intraplate volcanism fluctuate and is that determined by mantle dynamics deep-within the interior of the earth? How do these changes impact the inhabited surface of the planet, its climate and life support systems? These are some of the questions we aim to address in IODP Exp. 395.Oceanic islands and plateaus provide strong evidence that significant fluxes of mass and energy are transferred from the Earth's interior to its surface by processes that are independent of the normal plate tectonic cycle. Whereas today, mid-ocean ridges account for ~95% of the mass and energy flux from the mantle, in the past, the contribution from hotspot volcanism has been as high as 50%. Such pulses of magmatism are implemented in climate change, mass extinctions, geomagnetic field anomalies and higher rates of seafloor spreading, hydrothermal activity, and continental break-up. Yet these pulses of excessive volcanism are episodic across a range of time scales. Understanding these, their periodicity and processes, are essential if we are to gain an insight into mantle dynamics and Earth evolution.In this proposal, we aim to test hypotheses for the origin and affects of the hotspot responsible for the formation of the Iceland plateau. Through its interaction with the adjacent, slow-spreading Reykjanes Ridge, we aim to recover a record of Icelandic hotspot volcanism and its variability over the past 35Ma. Specifically IODP Exp.395 will investigate whether hotspot mantle upwells beneath Iceland and advects laterally along the ridge. Fluctuations in melt production from the Iceland hotspot are indicated by a nested suit of diachronous V-shaped ridges that form the flanks of the Reykjanes Ridge. By sampling across these V-shaped ridges, we will explore whether they are caused by fluctuations in the hotspot mantle flux, temperature or composition. In addition, we will investigate the chemical aging of oceanic crust as it is affected by an adjacent hotspot.Study of the Iceland-Reykjanes Ridge couplet is widely recognised as a type example of hotspot-ridge interaction. The outcome of this study will be a greater understanding of mantle hotspot dynamics and their impact on ocean basin evolution, the surrounding land masses, climate and ocean circulation.