Palaeoenvironmental interpretations based on molluscs from mid-Holocene lacustrine limestones, Mato Grosso do Sul, Brazil

摘要: In central Brazil there are continental carbonate rocks in three different geological contexts – the Pleistocene wackestones Corumba city (Xaraies Formation), mid-Holocene limestones lenses Pantanal Plain (Pantanal do Miranda) and old modern tufas Serra da Bodoquena (Serra Formation). We present here a systematic taphonomic study of molluscs found deposits Miranda, which provide information concerning palaeoenvironments these two distinct areas. Seven molluscan species were found: gastropods Marisa sp., Pomacea canaliculata, an unidentified hydrobiid, Idiopyrgus Biomphalaria sp. Megalobulimus bivalve Pisidium The include still living area today, supports Holocene age for limestones, as indicated by published 14C dates. Overall, data obtained from carbonates suggest freshwater environment with minimal current-wave action, probably fed springs, close to terrestrial environment, view assemblage composed lacustrine palaeoenvironment Miranda was different, presence absence shallow-water such predominantly aquatic amphibious; they younger than reported fine-grained area.