TY  - GEN
A1  - Cabato, Edweena Joan Alincastre
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/7305/
N2  - Volcanic eruptions remain a crucial part of human existence, yet many aspects of volcanic systems continue to elude comprehension. The frontier of geochemistry therefore, is also occupied with new tools and schemes to explain more of the magmatic enigma. Among these new approaches is the use of the light elements lithium, beryllium and boron and their isotopes: incompatible in common mineral phases in the magma and sensitive as tracers of source components and material recycling in subduction zones. Analyses through Secondary Ion Mass Spectrometry (SIMS) yield Li, Be and B concentration and d7Li profiles that have extraordinary implications on our present knowledge of crystal formation and volcanic eruptions. Populations of plagioclase, pyroxene and olivine phenocrysts in the Nea Kameni dacites and Thera andesites reveal complex and disparate crystallisation histories suggestive of magma injection, mixing and/or mingling. These processes are of particular importance in understanding volcanic systems because mafic intrusions may trigger explosive silicic eruptions, as already observed in several volcanoes. An even more significant, and no less surprising, offshoot of light element analyses in this study are the estimates for magma residence time using certain plagioclase phenocrysts. If our present knowledge of Li diffusion and partition coefficients were correct, data on these phenocrysts suggest very short residence times that could preserve primary Li abundances in entire crystals or their overgrowths. Such indicate extremely rapid crystallisation, occurring within hours, possibly due to decompression and degassing, immediately before or even during eruption. Being one of the first attempts at investigating the behaviour of the three lithophile light elements in situ and in detail, this work further attests to the affluence of information to be derived from phenocrysts. These may start to form early in the magma and continue to grow through varying physico-chemical conditions, forming an archive of crystallisation histories and magma geneses. Hence, these phenocrysts contribute not only to our understanding of the volcanic centre being considered, but would have implications on similar magma systems as well. It is therefore also the aim of this study to forge further investigations on crystals or inclusions, which could yield information that would otherwise be lost in bulk analyses. Through such meticulous work we shall definitely learn more about the driving mechanisms within volcanoes. For some people, this could mean avoiding life-threatening outbursts.
AV  - public
Y1  - 2007///
TI  - Abundances of Lithium, Beryllium and Boron in Phenocrysts from Santorini Volcano (Greece): Implications on Magma Genesis and Eruption Mechanisms
KW  - light elements 
KW  -  magma mixing 
KW  -  magma residence time
ID  - heidok7305
ER  -