Testing and refining the chronology and correlation of Mediterranean pollen records of late Last Glacial age using tephrochronology. / Hardiman, Mark.

2012. 377 p.

Research output: ThesisDoctoral Thesis

Unpublished

Documents

Abstract

Six terrestrial basin sites from across the Mediterranean region were investigated for cryptotephra content in order to construct site-specific tephrostratigraphies, with a focus on the latter part of the Last Glacial period. Two of the sequences were located in Spain (Padul, Villarquemado), one in Italy (Fimon), two in Greece (Tenaghi Philippon, Kopais) and one on the Greek Island of Lesvos. High resolution pollen stratigraphies and other proxy records were available for each sequence, characteristics of which have been used (in previous research) to form chronological frameworks and correlations between the records. This project aimed to use tephra isochrones to (1) test and refine the age models that underpin each of the records, and (2) correlate between the palaeo-records. The geographical spread of the sites studied here also allows the current tephrostratigraphic framework for southern Europe to be extended into areas for which tephra layers dating to the Last Glacial period had not previously been reported.

The two Spanish sites contained no or insignificant amounts of tephra. The other four sites each contained a number of tephra layers. Over 30 discrete tephra layers were identified, most of which were classified as cryptotephra. Geochemical characterisation of major, minor and trace elements were obtained using EPMA-WDS, LA-ICP-MS and SIMS micro-analytical methods. Correlations of tephra layers were based on graphical comparison of the geochemical data-sets to a developing data-base of the representative glass chemical compositions of European proximal and distal tephra deposits. The age estimates of key tephra isochrones were compared with other chronological information using Bayesian-based methods to develop revised age-depth models for each palaeo-record, the results being compared with the original age-depth models generated for each record.

The key outcomes of this study are: (1) some important tephro-correlations enable the degree of synchronicity of proxy response to rapid climatic shifts to be assessed across broad geographical regions; (2) the new tephrochronological results reveal significant chronological off-sets between records previously aligned using curve or ‘wiggle’ matching and by other independent chronological methods; and (3) previously unknown tephra layers originating from Santorini have been detected and their placement within the existing tephrostratigraphic framework of the Eastern Mediterranean proposed.
Original languageEnglish
QualificationPh.D.
Awarding Institution
Supervisors/Advisors
Award date1 Dec 2012
Publication statusUnpublished - 2012
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