Late Glacial and Holocene molluscan assemblages in deposits filling palaeolakes in northern Poland

Late Gla cial and Ho lo cene car bon ate lac us trine de pos its de vel oped as lac us trine chalk and cal car e ous gyttja are fairly wide spread across north ern Po land. They form fill ings of palaeolakes which de vel oped dur ing the deglaciation. These for ma tions are usu ally cov ered by peat. Rich and di ver si fied malacofauna has been found in the afore men tioned sed i -ments. The pro files from 154 sites de scribed and pub lished by var i ous au thors were sub jected to malacological anal y -sis. In the whole ma te rial, 18 mol lus can as sem blages were dis tin guished, rep re sent ing three types of hab i tats: terrestrial,of tem po rary wa ter bod ies, and of per ma nent wa ter bod ies. The com po si tion and struc ture of these as sem blages al lows char ac ter iz ing cli mate and dif fer en ti at ing hab i tats. The time-se quences of malacological as sem blages pro videdpos si bil ity to de fine three types of malacological se quences. On the ba sis of these suc ces sions, a scheme of the lakewa ter bod ies evo lu tion dur ing Late Gla cial and in north ern Po land was elab o rated.