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

地幔热柱有脉动吗？板内火山活动会波动吗？这是由地球内部深处的地幔动力学决定的吗？这些变化如何影响地球上有人居住的表面、气候和生命维持系统？这些是我们打算在IODP Exp中解决的一些问题。395.大洋岛和高原提供了强有力的证据，表明大量的质量和能量通量通过独立于正常板块构造周期的过程从地球内部转移到地球表面。而今天，大洋中脊占来自地幔的质量和能量通量的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、大规模灭绝、地磁场异常以及海底扩张、热液活动和大陆解体的更高速率中实现。然而，这些过度火山活动的脉冲在一系列时间尺度上是间歇性的。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至关重要的。在这个提议中，我们的目标是检验有关冰岛高原形成的热点的起源和影响的假说。通过它与邻近的缓慢扩张的雷克扬斯山脊的相互作用，我们的目标是恢复冰岛热点火山活动的记录及其在过去35 Ma的变化。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海脊横向平流。冰岛热点地区熔体产量的波动由一套沿时嵌套的V形山脊表示，这些山脊形成了雷克扬斯山脊的侧翼。通过对这些V形山脊的采样，我们将探索它们是否是由热点地幔流量、温度或成分的波动造成的。此外，我们还将研究洋壳的化学老化，因为它受到邻近热点的影响。冰岛-雷克雅内斯海脊耦合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的动力学及其对洋盆演化、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.