Supervolcanoes under the sea

10 Apr 2010

At id1847871 April 8th ... scientists have been looking at a 145 million years old supervolcano on the ocean floor east of Japan. Known as Shatsky Rise it is composed of a huge outflowing of magma, some individual flows being as much as 75 feet thick. Geologists have argued about the formation and origin of large oceanic plateau - the mystery being in the origin of the magma. Was it deep mantle or from a shallower depth? They also seem to occur at the boundaries of tectonic plates. One surprise was that sediments and microfossils indicate parts of the Shatsky Rise plateau was at one time above sea level - it is now 2 miles below the surface. It formed an archepelago during the early Cretaceous (about 145 million years ago). It also formed at a time when this region of the world was at or near the equator. This last point seems to have a bearing on a post a couple of days ago - amber foun d in Africa near the equator. However, amber resin comes from pine trees that grew in Ethiopia during the Cretaceous period. Hence, if the equator was somewhere near Japan this suggests the pine trees could well have been living in a much cooler environment (in spite of the modern day location). Is the continental drift theory an adequate explanation for this movement?