Palaeocene-Recent plate boundaries in the NE Atlantic and the formation of the Jan Mayen microcontinent

Abstract: Breakup and sea-floor spreading between Greenland and Eurasia established a series of new plate boundaries in the North Atlantic region since the Late Palaeocene. A conventional kinematic model from pre-breakup to the present day assumes that Eurasia and Greenland moved apart as a two-plate system. However, new regional geophysical datasets and quantitative kinematic parameters indicate that this system underwent several adjustments since its inception and suggest that additional short-lived plate boundaries existed in the NE Atlantic. Among the consequences of numerous plate boundary relocations is the formation of a highly extended or even fragmented Jan Mayen microcontinent and subsequent deformation of its margins and surrounding regions. The major Oligocene plate boundary reorganization (and microcontinent formation) might have been precluded by various ridge propagations and/or short-lived triple junctions NE and possibly SW of the Jan Mayen microcontinent from the inception of sea-floor spreading (54 Ma) to C18 (40 Ma). Our model implies a series of failed ridges offshore the Faeroe Islands, a northern propagation of the Aegir Ridge NE of the Jan Mayen microcontinent, and a series of triple junctions and/or propagators in the southern Greenland Basin. As a generally accepted model, northward propagation of sea-floor spreading from the central North Atlantic (between North America and Eurasia) rifted Greenland from Eurasia (e.g. Pitman & Talwani 1972; Srivastava & Tapscott 1986) and formed a triple junction with an existing active plate boundary between the North American plate and Greenland (Fig. 1) (Srivastava &amp