HR: 1340h
AN: V43E-1458    [Abstracts]
TI: Geochemistry of Late Quaternary Terrestrial Tephra Deposits From the Eastern Mediterranean
AU: * Hart, J S
EM: jo_themanor@yahoo.com
AF: University of Wales, Aberystwyth, Institute of Geography and Earth Sciences, Llandinam Building, Penglais Campus, UWA, Aberystwyth, SY23 3DB United Kingdom
AU: Pearce, N J
EM: njp@aber.ac.uk
AF: University of Wales, Aberystwyth, Institute of Geography and Earth Sciences, Llandinam Building, Penglais Campus, UWA, Aberystwyth, SY23 3DB United Kingdom
AU: Eastwood, W J
EM: w.j.eastwood@bham.ac.uk
AF: University of Birmingham, School of Geography and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT United Kingdom
AB: Tephra layers provide geologists and archaeologists with isochronous marker deposits, which, if interpreted correctly, can provide valuable chronostratigraphic information. Explosive volcanic activity in the Hellenic arc over the last 150 000 years has left a record of terrestrial, lacustrine and marine tephra deposits across the Aegean and western Anatolia which are of great value in stratigraphic correlation. Some of these eruptions have produced substantial volumes of ash (e.g. Kos, 150 ka, Santorini 3600 years BP) and for stratigraphic correlation accurate recognition of these individual tephra deposits is imperative. This project investigates the tephrochronology of the Eastern Mediterranean which is believed to be important in two contexts, (i) in placing time constraints on the evolution of civilisations in that area and (ii) in understanding the evolution of the Hellenic arc. Results from analysis of single glass shards from tephra deposits on Kos, Yiali, Rhodes and Santorini as well as other minor islands and selected sites in Turkey are presented. Major and trace elements were analysed by electron probe, ion probe and LA-ICP-MS techniques. A trace element database has been generated for both distal and proximal samples and has aided in the understanding of the magma chamber evolution of the volcanoes in question. These analyses also provide a detailed, single grain, chemical stratigraphy of many islands which will enable temporal and spatial correlations and ultimately, will aid in the discussions of the impact volcanic eruptions exerted upon Aegean civilisations. Arguments related to the timing of Santormi's eruptions are considered and data are also-presented for tephra from the Alaskan volcano, Aniakchak. Thus, adding further weight to disproving a 1645 BC date for the Minoan eruption, but confirming the time of the eruption of Aniakchak. Finally the study provides a comparison between two trace element analytical techniques, ion probe and the LA-ICP-MS. This serves to increase confidence in comparisons between previous studies which employed these techniques.
DE: 8404 Ash deposits
DE: 8499 General or miscellaneous
DE: 3655 Major element composition
DE: 3670 Minor and trace element composition
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting