Comparison of oceanic island lava flow suites separated by a lateral collapse - how does a major structural change impact on the magma supply system? (original) (raw)

2014

Abstract

The massive ~530 ka Cumbre Nueva collapse on the Canary Island of La Palma separates the pre-collapse Cumbre Nueva rift sequence from the post-collapse Bejenado edifice. Such collapses are characteristic of the shield stage of oceanic island growth, and these Canarian volcanoes form an ideal case study to determine how the composition of lavas produced within a magma supply system varies in response to the structural evolution of the island. The Cumbre Nueva rift formed as the result of focused activity along a central rift zone, with the flanks of the edifice becoming progressively more unstable as growth continued. Conversely, the Bejenado volcano erupted entirely within the collapse embayment in a brief, intense period of activity after which volcanism permanently ceased. All flows are composed of alkaline trend lavas, including basanites, tephrites, tephriphonolites and porphyritic ankaramites, with lavas from both edifices showing a tendency towards increased evolution over tim...

Hilary Downes hasn't uploaded this paper.

Let Hilary know you want this paper to be uploaded.

Ask for this paper to be uploaded.