Wetlands in the Venetian Po Plain (northeastern Italy) during the Last Glacial Maximum: Interplay between vegetation, hydrology and sedimentary environment

摘要: Abstract In the low Venetian plain (northeastern Italy) thick sequences of silt and sand layers alternate with common, thin peat organic silt; in topmost 30 m Late Pleistocene alluvial series span between 23,000 14,000 yr BP (radiocarbon dating), an area measuring 100 km by 30 km. They indicate broad areas where wetlands developed. We aim to understand features origin undertaking sedimentological, pollen, non-pollen palynomorph plant macrofossil analyses. Thirteen cores were drilled central zone near coast Adriatic Sea 79 samples analysed. The palaeoenvironmental reconstruction based on previous pollen analysis did not emphasize formed, suggesting a homogenous steppe environment, typical cold dry climate. probably waterlogged for most year allowing formation development local communities mainly aquatic species. Macrofossil analyses suggest that herbaceous plants, such as Cyperaceae Poaceae (probably Carex fusca Phragmites australis ), brown mosses (mainly Scorpidium scorpioides ) important components wetland communities. Fossils obligate organisms open water environments, these include macrofossils Nymphaea , Characeae, Bryozoa Potamogeton palynomorphs algal resting cells, free cells colonies (Zygnemataceae, Spirogyra Mougeotia Closterium idiosporum Type 225, 229, Botryococcus Pediastrum cf. boryanum P . simplex Ceratium hirundinella Tetraedron minimum 333), oocytes invertebrates (Type 353A 353B) incompletely known types 303, 74, 128A 128B). A discontinuous occurrence fungal spores other microfossils 200, Gaeumannomyces 126), Glomus 207), 351, 79, types) suggests frequent fluctuations depth periodic emersions bottom ponds or fens. quality preferred identified species, suggested literature fossil types, is eutrophic mesotrophic rich cations. Peatland formed wide, low-lying fluvial ridges which periodically inundated fluctuating groundwater. Peat accumulated continuous only fen deposition prevailed minerogenic sediment. When buried deposit, level was incorporated into stratigraphic record.