Sedimentological variability and depositional environment of the Anthemountas River (Northern Greece) during the Late Pleistocene and Holocene

Abstract

Research has shown that fluvial systems exhibit a rapid response to extreme events, such as floods or climate-tectonic interplay, the evidence of which is recorded in fluvial sediments. This article provides new data and insights into the reconstruction of the Anthemountas River depositional environment. The study was conducted with granulometric analysis and with the lithostratigraphic and chronostratigraphic description of approximately 20000 yr B.P., the area's most extended sedimentary sequence to date. The evolution of the Anthemountas River Valley during the Late Pleistocene and Holocene is closely linked to tectonic activity and changes in the sea-level and climate. The interpretation of grain size cumulative curves, frequency curves, and the Passega C-M diagram is used in conjunction with the textural parameters of the sediments to obtain information about the means of transport and the intensity of environmental conditions. In addition, the loss on ignition method was used to estimate two parameters; organic matter and carbonates. Chronostratigraphic details were also obtained from the A.M.S. dating of charcoal samples. The analysis has identified the Late Pleistocene aggradation materials and the transition to the Holocene. Sedimentation can be described as a fluvial valley-fill sequence with periodical in-channel, off-channel, and floodplain series. After 3500 cal. B.P., the area is affected by the possible formation of a bay-head delta, with fluvial-dominated sands and the development of stable floodplains. Finally, the fluvial records of the Anthemountas River reveal phases of hydrological activity and stability.