RECONSTRUCTIONS OF THE ARCTIC - MESOZOIC TO PRESENT

Plate reconstructions using both geological and geophysical data are reviewed and examined. The Arctic Ocean opened in three stages: anomaly 24 25 time to the present when documented seafloor spreading occurred in the Eurasia Basin. The middle event occurred from anomalies 34 to 25 when interaction of the North American and Eurasian plates caused crustal shortening or strike-slip motion in the Arctic. The first event occurred from prior to anomaly 34 time when the Amerasia Basin opened by a rotation with some translation about a pole near the Beaufort-Mackenzie Basin. Crustal shortening caused by this rotation may have been accommodated in the Brooks Range and in the South Anyui Suture Zone. The Alpha Ridge was formed during the opening of the ocean but was not the spreading centre. It is a feature similar to the Iceland-Faeroe Ridge. Prior to the onset of seafloor spreading in the Amerasia Basin the circum-Arctic sedimentary basins formed during a long period of rifting. © 1990.