sentences:  The existence of a subglacial lake in the Vostok region was first suggested by Russian geographer Andrey Kapitsa based on seismic soundings made during the Soviet Antarctic Expeditions in 1959 and 1964 to measure the thickness of the ice sheet.The continued research by Russian and British scientists led by 1993 to the final confirmation of the existence of the lake by J. P. Ridley using ERS-1 laser altimetry.The overlying ice provides a continuous paleoclimatic record of 400,000 years, although the lake water itself may have been isolated for 15 to 25 million years.