NEW INSIGHTS INTO THE EVOLUTION OF THE LOMONOSOV RIDGE AND THE EURASIAN BASIN

The international expedition ARCTIC'91 has yielded new results concern ing the evolution of the Eurasian Basin. Seismic reflection data were acquired with a total line length of 1500km in the Eurasian Basin. The signals imaged the whole sedimentary cover down to the oceanic baseme nt. Together with detailed velocity information recorded by sonobuoys, these lines allow us to establish a stratigraphic model for the Euras ian Basin. Using both the structure of the seismic units and the aerom agnetic anomaly pattern, we date the subsidence of the Lomonosov Ridge below sea-level at chron 22 time. Furthermore, the data indicate a dr amatic change in sedimentation style at approximately chron 13 time. O ur estimates of the sedimentation rates reveal a decrease from more th an 10 cm kyr(-1) to 1.5 cm kyr(-1). The sedimentation from the adjacen t continental margins decreased to modern rates from that time on for the investigated part of the Arctic Ocean.