A PUMP FREEZE CORER FOR RECENT SEDIMENTS

A new freeze corer consists of thermos, a pump unit, and a thin wedge- shaped freeze container. Methanol, or ethanol, and dry ice are filled in the thermos. The cold alcohol is pumped down into the freeze wedge and the sediment freezes to the outside. Compared to previous freeze c orers, this the causes less disturbance of sediment stratigraphy an gi ves thicker crusts of frozen sediments. The current corer device is de signed to take cores (< 50 cm long) of recent sediments from ice-cover ed lakes but could be modified for coring from boat. Moreover, the pum p concept could allow freeze coring in very deep lakes or on the conti nental shelf (< 200 m).