 Another period of volcanic activity began in the same region about 55 million years ago during the Eocene period when the north-south trending Mid-Atlantic Ridge began to form under the northern Atlantic Ocean east of Greenland.The cause of this volcanism might be related to partial melting from movement of a transform fault system extending from Labrador Sea to the south and Baffin Bay to the north.Although the region was carried away from the Iceland plume by going plate motion over millions of years, the source of the partial melting for the final period of volcanic activity may have been remnants of still anomalously hot Iceland plume magma which were left stranded beneath the North American lithosphere in the Paleocene period.