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Cyclical summit collapse events at Ascraeus Mons, Mars.

Scott, Evelyn D. and Wilson, Lionel (2000) Cyclical summit collapse events at Ascraeus Mons, Mars. Journal of the Geological Society, London, 157 (6). pp. 1101-1106. ISSN 0016-7649

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Abstract

The sequential development of multiple summit calderas of shield volcanoes gives clues about how the spatial location of shallow magma chambers evolves with time and how the magma supply into these chambers evolves. We re-interpret the sequence in which caldera collapse events took place at the Martian shield volcano Ascraeus Mons and argue that the formation of the central caldera, usually accepted to be the most recent, was followed by two further collapse events. We also present structural evidence for an early, large central caldera and, therefore, also an early large magma reservoir. This challenges the current hypothesis for Ascraeus Mons that successive magma reservoirs have increased in size as this volcano matured and that a reservoir occupied a central location within the volcano only at the end of its active lifespan. We propose that there has been a cyclical oscillation in the site of shallow storage of magma at Ascraeus Mons between central and peripheral magma reservoirs. The earliest reservoir formed centrally, but magma was subsequently redirected into peripheral reservoirs, over which the peripheral calderas formed. Later, the central location was utilized again, only to be followed once more by a development of peripheral storage reservoirs. This alternating pattern implies substantial variations with position and time in both the magma supply rate from the Martian mantle and the distribution of stresses within the volcanic edifice.

Item Type: Article
Journal or Publication Title: Journal of the Geological Society, London
Uncontrolled Keywords: Mars ; Ascraeus Mons ; tectonics ; volcanism ; calderas
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 21662
Deposited By: ep_ss_importer
Deposited On: 23 Jan 2009 16:38
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:50
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/21662

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