Abstract: Thermal hot waters are known in the terrestrial areas in the vicinity of Gülbahçe Bay. The main targetof this study is to examine the presence of these hot water sources. A high-resolution shallow seismicstudy (3.5 kHz) was used to determine the high potential hydrothermal area in Gülbahçe Bay andsediment samples were collected by gravity corer at 14 points for palynological analysis. Thepalynological findings obtained from these core samples were confronted with a "Reference sample",which came from outside the study area and is thought to be able to change with the thermal features ofenvironment. . Concerning the seismic profiles obtained from Gülbahçe Bay, it has been suggested that the highson the sea bottom were formed from clustered corals, and this has been observed to be common in hotwater conditions. In the bay these highs cover an area of approcimately 16km². The palynologicalresults obtained from the sediment samples in Gülbahçe Bay determined terrestrial and marinepaleoenvironmental conditions for the Late Holocene period. High palaeotopographic and lowlandareas surrounding the Gülbahçe Bay are covered by Pinus, Castanea, Quercus and Oleaeceae, Ulmus,and Cyrillaceae. Nyssa, Taxodiaceae and Cupressaceae are grown in the narrow areas of freshwatermarsh, and between these areas there are constricted open vegetation areas which are characterized byAsteraceae, Cichorioideae, Greniaceae, Artemisia, Ephedraceae and Chenopodiaceae. Due to the rarepresence of the some dinoflagellat cyst (Lingulodinium machaerophorum, Cymatiosphaera globulosa,Spiniferites ramosus and Spiniferites spp.), the Late Holocene period dating is supported. Additionally,these palynomorphs are accompanied by Pseudoschizaea (seldom) and microforaminiferal test(abundantly), and this cooperation could suggest the presence of a hot water outlet in Gülbahçe Bayduring the Late Holocene period. It can be said that the iron oxide that formed on the microforaminiferal test and variouspalynomorphs is related to the thermal activity in Gülbahçe Bay. According to the palynoflora definedin this study, there could have been humid and hot palaeoclimatic conditions in the study area.Additionally, the “coexistence approach” analysis was used on the palynoflora of the Late Holocene,and numerical palaeoclimatic values were obtained. These results are compared with results from somepalynoflora of the Late Holocene.