LITHOSTRATIGRAPHIC RECONSTRUCTION OF A LATE QUATERNARY MULTIPLE PALAEOVALLEY SYSTEM FROM THE ADRIATIC COASTAL PLAIN (CHIENTI RIVER, CENTRAL ITALY): IMPLICATIONS FOR ENVIRONMENTAL AND CLIMATE-RELATED CHANGE

This study presents a high-resolution, multi-proxy investigation of the Late Quaternary three-dimensional stratigraphic architecture of the Chienti River incised-valley system, located along the southern coastal plain of the Marche Region (east-central Italy). The primary objective is to reconstruct the depositional history of this fluvio-coastal environment and assess its response to glacio-eustatic sea-level fluctuations over the last ~120 ka, providing insights into present and future environmental change. Lithostratigraphic data from 490 boreholes are integrated with sedimentological, palynological and micropalaeontological analyses, together with radiocarbon dating, on two reference cores drilled near the present coastline. Facies analysis, supported by penetrometer tests and palaeoecological data, documents a composite incised-valley system generated by multiple phases of fluvial incision and subsequent aggradation. Cross-sectional correlation panels delineate a complex valley-fill architecture, with stacked erosional surfaces and fluvial units whose timing is tentatively linked to Late Pleistocene glacio-eustatic lowstands and the subsequent transgressive-regressive cycle. The valley fill is overwhelmingly fluvial in character, comprising channel, floodplain and swamp deposits, whereas marine influence is restricted to a thin interval of inner-estuarine deposits that records the maximum landward extent of sea-level rise. These results refine the Late Quaternary stratigraphic framework of the lower Chienti coastal plain and improve understanding of the response of small Mediterranean river systems to high-frequency sea-level and climate oscillations.