Textural analysis of magmatic enclaves from the Kameni Islands, Santorini, Greece.

Martin, V. M. and Holness, M. B. and Pyle, D. M. (2006) Textural analysis of magmatic enclaves from the Kameni Islands, Santorini, Greece. Journal of Volcanology and Geothermal Research, 154. pp. 89-102. DOI https://doi.org/10.1016/j.jvolgeores.2005.09.021

[img] PDF
HolnessTextural.pdf
Restricted to Registered users only

Download (836kB)

Abstract

The Kameni Islands have been the focus of historic volcanic activity on Santorini, Greece. The islands comprise a series of dacite lavas, the erupted compositions of which have remained approximately constant for the last ∼2200 years. The dacite lava flows of Nea Kameni contain a variety of mafic enclaves, distinguished by differences in texture, composition and mechanical behaviour. The mafic enclaves represent chilled fragments of mafic magma that crystallised rapidly on contact with the cooler, more silicic host magma. The absence of chilled margins on the enclaves suggests that the replenishing magma initially formed a dense layer at the base of the chamber. Groundmass textures are interpreted as an indication of the degree of undercooling between the enclaves and the host. Groundmass textural information obtained from the enclaves has been used to determine the relative volumes of replenishing magmas injected into the host magma before eruption, which indicates that the volume of erupted magma is directly proportional to the volume of replenishing magma emplaced in the chamber prior to eruption, which thus may act as a potential eruption trigger. The variety of replenishing magmas implies the existence of a complex conduit and chamber system beneath Santorini volcano. Andesitic enclaves with linear crystal size distributions are thought to have originated as an aphyric andesitic melt expelled from a crystal mush by filter-pressing. Disequilibrium phenocryst assemblages in the lavas and phenocryst-bearing enclaves provide evidence for the entrainment and recycling of older phenocryst populations.

Item Type: Article
Uncontrolled Keywords: 2006 AREP IA49 IA51 2006 P
Divisions: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Journal or Publication Title: Journal of Volcanology and Geothermal Research
Volume: 154
Page Range: pp. 89-102
Identification Number: https://doi.org/10.1016/j.jvolgeores.2005.09.021
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:03
Last Modified: 23 Jul 2013 10:07
URI: http://eprints.esc.cam.ac.uk/id/eprint/514

Actions (login required)

View Item View Item

About cookies