Mount Etna–Iblean volcanism caused by rollback-induced upper mantle upwelling around the Ionian slab edge: An alternative to the plume model
Mount Etna–Iblean volcanism caused by rollback-induced upper mantle upwelling around the Ionian slab edge: An alternative to the plume model
复制标题
埃特纳火山-伊布尔火山活动是由回滚引起的上地幔围绕爱奥尼亚板片边缘上涌引起的：地幔柱模型的替代方案
作者：
W. Schellart
西西里（意大利）埃特纳火山（0.5 Ma至今）和伊布尔高原（约100 Ma）的火山活动。7.0-1.1 Ma）仍然是一个谜，因为它位于卡拉布里亚俯冲带附近，但横向偏离。以前的研究表明，火山活动是由地幔柱或横向地幔流从非洲下面通过岩石圈台阶上的板状窗口造成的。在这里，我建议，埃特纳山和伊卜拉火山有关的上地幔物质，是流动的南部爱奥尼亚板块边缘，以适应东向回滚的爱奥尼亚板块，在晚中新世恢复减压熔融。新的三维流体动力学俯冲模型表明，回滚引起的地幔回流发生在一个准环形的方式与下降流的组件直接低于和高于板，和上升流的组件旁边的俯冲带与最大的上升流观察旁边的subslab区域。在90-430 km深度观察到显著的上升流（≥最大值的71%），并在板片边缘以上从推断的弧岩浆活动的投影距离延伸55-660 km。这些模型可以解释在过去的2.7亿年里，西西里的板内火山活动和弧岩浆活动之间长达430公里的巨大空间间隔，以及它们的同期活动。模型中的最大上升流速度约占沟回滚速度的32%。在过去的1800万年里，滚退速度高达10-19厘米/年，这些模型预测，在西西里以下，最大回滚引起的上地幔上涌速度为3.2-6.1厘米/年。
Volcanism in Sicily (Italy) at Mount Etna (0.5 Ma to present) and the Iblean Plateau (ca. 7.0–1.1 Ma) remains enigmatic, because it is located in close proximity to, but is laterally offset from, the Calabrian subduction zone. Previous work suggests that the volcanism results from a plume or from lateral mantle flow from underneath Africa through a slab window across a lithospheric step. Here I propose that Mount Etna and the Iblean volcanics are related to decompression melting of upper mantle material that is flowing around the southern Ionian slab edge to accommodate east-directed rollback of the Ionian slab that resumed in the Late Miocene. New three-dimensional fluid dynamic subduction models demonstrate that rollback-induced mantle return flow occurs in a quasi-toroidal fashion with a component of downwelling directly below and above the slab, and a component of upwelling next to the subduction zone with maximum upwelling observed next to the subslab region. Significant upwelling (≥71% of the maximum) is observed at 90–430 km depth and extends 55–660 km away from the projected distance of inferred arc magmatism above the slab edge. The models can explain the large spatial separation of as much as 430 km between intraplate volcanism in Sicily and arc magmatism during the past ∼7 m.y., and their contemporaneous activity. The maximum upwelling velocity in the models composes 32% of the trench rollback velocity. With rollback velocities up to 10–19 cm/yr during the past ∼8 m.y., the models predict maximum rollback-induced upper mantle upwelling velocities of 3.2–6.1 cm/yr below Sicily.