Μελέτη της εσωτερικής μικρομορφολογίας και απολίθωσης καινωζωΐκών σπονδυλόζωων μέσω ραδιοαναλυτικών τεχνικών

Abstract

This thesis concerns the study of bone and tooth diagenesis in two Greek and one Cypriot fossilisiferous sites. Diagenesis is a term that was introduced during the last two decades in order to describe the fossilization processes that affect bones and teeth and that lead to their preservation through time, as they pass on from the biosphere to the lithosphere. Diagenesis of skeletal material is a highly complex phenomenon and has remained controversial despite many studies during the last decades. The material used during this study consists of 55 bones and 50 teeth of Cenozoic vertebrates and numerous reference materials. Specifically, the material derived from the Greek sites (Pikermi & Chalkoutsi, Attica) consists of skeletal remains of the species Hipparion sp., which are of Upper Miocene age. On the other hand, the material coming from the site from Cyprus (Aghia Napa) consists of skeletal remains of the dwarf Hippopotamus of Cyprus, Phanourios minor and is of Upper Pleistocene age. Because of the extremely complex character of diagenesis and the numerous processes of which it consists, various analytical techniques and methods have been applied through the years, in order for it to be understood and described. During our own study, we used Scanning Electron Microscopy and X-ray microanalysis, Transmittance Electron Microscopy, X-ray Diffraction & the Rietveld Method, Infrared Spectroscopy (Attenuated Total Reflectance Spectroscopy & Near Infrared Spectroscopy), Microprobe Analysis, LA-ICP-AES, ICP-MS and Ion Chromatography. Some applications of these techniques were used on skeletal material for the first time and have lead to interesting results that we believe could contribute towards the understanding of diagenesis and the development of appropriate methodology. Also, we were able to describe the diagenetic profiles of each fossilisiferous sites, based on their morphological, histological, structural, spectral and chemical characteristics. These results allow for linking the diagenesis of skeletal material to the local geochemical conditions. From the results of this study, it is obvious that concerning the site of origin, diagenetic alterations are most visible in the material coming from Chalkoutsi and least present in that of Aghia Napa. In general, it seems that enamel is the tissue least affected by diagenesis while bone and dentine present comparable diagenetic features. It is suggested that this approach could possibly provide the means to “measure” the extent of bone and dentine diagenesis employing enamel as a reference material

Τα ζητήματα που μελετήθηκαν στα πλαίσια της διατριβής αυτής περιλαμβάνουν θέματα ιστολογίας των σκληρών ιστών των σπονδυλοζώων, χημείας και δομής βιογενών και ορυκτών απατιτών, και εν μέρει γεωχημείας των περιβαλλόντων ταφής. Μέσω των δειγμάτων που μελετήθηκαν έγινε προσπάθεια συγκριτικής μελέτης τριών σημαντικών απολιθωματοφόρων θέσεων με σπονδυλωτά (Πικέρμι, Χαλκούτσι και Αγία Νάπα) αλλά και τριών διαφορετικών τύπων σκληρών ιστών (οστό, οδοντίνη και αδαμαντίνη). Διερευνήθηκαν ερωτήματα που μέχρι σήμερα παραμένουν αναπάντητα, με την ελπίδα της συμβολής στην κατανόηση των διαγενετικών διεργασιών που επιδρούν σε σκελετικά στοιχεία, αλλά και στην ανάπτυξη