The investigation has been focused on biological materials (bone, teeth), water systems, sediment deposition and other environments that can provide information for dating, origin as well as evolution and recovery of palaeoenvironment and palaeoecology. The analysis of 13C, 18O and 14C isotopes in materials such as bones, speleothems, carbonate sediments, etc., which varies, depending on climatic changes, can supply also information for palaeoenvironment reconstruction.
a) Bones and Teeth
During the last four decades, the analysis of radiocarbon and stable isotopes in terrestrial teeth and bones has provided valuable information about the palaeoclimatic and palaeoenvironmental conditions on the Quaternary period as well as palaeodiet habits for a variety of species. Oxygen and carbon comprise principal structural materials of skeleton and teeth. These elements mainly originate from the water and food that the animal consumes, and reflect the respective isotopic fingerprints of their original sources. Bones and teeth samples of Ursus ingressus from Loutra Arideas Cave (Greece) were used to determine the diet of this extinct species and to reconstruct the palaeoclimatic conditions. Several possible effects that may affect the isotopic composition of apatite were investigated, including age, sex, tooth type and diagenesis. Moreover the prehistoric (middle Neolithic, ~5500 BC, until the first stages of Early Chalcolithic, ~3500 BC) lakeside settlement of Dispilio (Northern Greece, Kastoria) have been studied based on animal bone and tooth findings. Sample treatment protocols were constructed for a sufficient secondary calcite removal as well as for bioapatite and collagen extraction. The organic phase of bones, as well as of soils, was subjected under radiocarbon dating (14C) in order to set the observed “shifts” in Neolithic frame
b) Land snail research for palaeoenvironmental changes in Greece
The combination of 14C ages, along with biostratigraphic and archaeological remains has been used to establish the cave’s chronology and the phases of human occupation from the late Pleistocene (Upper Palaeolithic) to the early Holocene (Mesolithic). This research deals with stable isotopic data (oxygen and carbon )and radiocarbon (14C) from late Pleistocene-Holocene (~13 to ~10,5 cal ka BP) shells of the gastropod helicid land snail Helix figulina, from Franchthi Cave (Greece). It aims to explore palaeoclimatic and palaeoenvironmental implications of isotope palaeoecology of archaeological shells at the time of human occupation of the cave. Radiocarbon analysis (14C), carried out mainly on charcoal. Modern shells of Helix figulina and other gastropod helicid species from around the cave (Eobania vermiculata and Cornu aspersum), were also analysed to compare with isotopic signatures of archaeological shells. Carbon isotope composition of modern shells (δ13Cs) depicts the consumption of C3 vegetation; no evidence for species-specific feeding behaviour and the contribution of other sources of carbon was observed. Shell oxygen isotopic values (δ18Os) are consistent with other Mediterranean snail shells from coastal areas. Combining empirical linear regression and an evaporative model (FBM), the δ18Os suggest that modern snails in the study area are active during periods of higher relative humidity (RH) and lower δ18Op, probably at night. Late glacial and early Holocene δ18Os show lower values compared to modern ones. Early Holocene δ18Os values likely track enhanced moisture and isotopic changes in the precipitation source (Mediterranean). By contrast lower late glacial δ18O could reflect lower temperatures and δ18Op, compared to present day. The results provide an innovative contribution to the discussion of the palaeoclimatic implications of shell δ18O. Interplaying variables, such as atmospheric and hydrological regime, may contribute to a different extent to δ18Os. Shell carbon isotopes indicate the presence of C3 vegetation as main source of carbon to late glacial and early Holocene snails. Estimated late glacial and early Holocene plant δ13C values approach that of some modern Mediterranean woody shrub species adapted to drought
c) Speleothems and soils
Secondary cave carbonates such as stalagmites have been used as great recorders of continental palaeo–environments. Assuming that speleothem calcite is deposited at or close to oxygen isotope equilibrium with cave dripwater the δ18O of the precipitated calcite reflects both the δ18O of the dripwater and the temperature at which calcite deposition occurs. Therefore speleothems from Kastoria caves were sampled and subjected under stable and radiogenic isotope analysis in order to confirm or not the conclusions for palaeoenvironmental conditions that were resulted from bone material regarding prehistoric settlement of Dispilio. At the same approach a soil drilling was performed in Dispilio prehistoric settlement were the palaeo-cost of Kastoria Lake was studied. Finally radiocarbon (14C) analysis of cores from the vicinity of Nea Nikomidiea has made it possible to unravel c. 10.000 years of sediment accumulation and associated palaeoenvironmental changes.