Department of Earth Sciences, Cambridge University , Madingley Road, Cambridge CB3 0EZ , UK.
Philos Trans A Math Phys Eng Sci. 2019 Feb 25;377(2139):20180010. doi: 10.1098/rsta.2018.0010.
We use both seismology and geobarometry to investigate the movement of melt through the volcanic crust of Iceland. We have captured melt in the act of moving within or through a series of sills ranging from the upper mantle to the shallow crust by the clusters of small earthquakes it produces as it forces its way upward. The melt is injected not just beneath the central volcanoes, but also at discrete locations along the rift zones and above the centre of the underlying mantle plume. We suggest that the high strain rates required to produce seismicity at depths of 10-25 km in a normally ductile part of the Icelandic crust are linked to the exsolution of carbon dioxide from the basaltic melts. The seismicity and geobarometry provide complementary information on the way that the melt moves through the crust, stalling and fractionating, and often freezing in one or more melt lenses on its way upwards: the seismicity shows what is happening instantaneously today, while the geobarometry gives constraints averaged over longer time scales on the depths of residence in the crust of melts prior to their eruption. This article is part of the Theo Murphy meeting issue 'Magma reservoir architecture and dynamics'.
我们利用地震学和地质压力计来研究冰岛火山地壳中熔体的运动。我们通过它在向上流动时产生的一系列小地震群，捕捉到了熔体在一系列岩脉中移动或穿过岩脉的行为，这些岩脉的范围从地幔上部延伸到浅层地壳。熔体不仅被注入到中央火山下方，还被注入到裂谷带的离散位置和下方地幔羽流的中心上方。我们认为，在冰岛地壳的正常韧性部分深处（10-25 公里）产生地震所需的高应变速率与二氧化碳从玄武熔体中离析有关。地震活动和地质压力计为熔体在通过地壳时的运动方式提供了互补信息，包括停滞、分馏，以及熔体在向上流动过程中经常在一个或多个熔体透镜中冻结：地震活动显示了今天正在发生的事情，而地质压力计则给出了在喷发之前熔体在地壳中停留的深度的较长时间尺度上的限制。本文是 Theo Murphy 会议议题“岩浆储层结构和动力学”的一部分。
