Stable isotope stratigraphy of travertine sequences from channel deposits at hierapolis of Phrygia (Denizli, Turkey)

Travertine sequences from petrified channels used in antiquity as water supply canals in the city of Hierapolis (Denizli, Turkey) for irrigation and domestic use were sampled and analyzed for stable isotopes composition. Data records from two channels show composite quasi-periodic variations. Radium-226 activity was measured to calculate temporal constrains; one of the channels, 182cm thick, deposited in 790±71 years, whereas the other, 644cm thick, in 995±71 years. Isotope data, studied through spectral and cross-spectral analysis, indicate that the different oscillation frequencies may be related to surface temperature and rainfall pulses.