Rocks from the
North Atlantic Igneous Province have been found in
Greenland, the
Irminger Basin,
Faroe Islands,
Vøring Plateau (off Norway),
Faroe-Shetland Basin,
Hebrides, Outer
Moray Firth and
Denmark. The supercontinent known as
Pangea existed during the late
Paleozoic and early
Mesozoic eras and began to
rift around 200 million years ago. Pangea had three major phases of breakup. • The first major phase began in the Early-Middle
Jurassic, taking place between North America and Africa. • The second major phase of breakup began in the Early
Cretaceous. The
South Atlantic Ocean opened around 140 million years ago as Africa separated from South America, and about the same time, India separated from Antarctica and Australia, forming the central
Indian Ocean. • The final major phase of breakup occurred in the early
Cenozoic, as
Laurentia separated from
Eurasia. The flow of hot plume material creates
volcanism under the
continental lithosphere. Iceland extends across the
Mid-Atlantic Ridge. The Mid-Atlantic Ridge is a
divergent plate boundary, and it separates the Eurasian and North American plates. The ages of the earliest volcanic rocks from this plume lie in the late
Paleocene, and both sides of the Atlantic Ocean contain these rocks. Since these rocks have been dated to the late Paleocene, this lines up with the time of breakup of the North Atlantic continent, so some think it could have been a contributing factor. Volcanism thus occurs where the crust is easier to break up because it has been stretched by lithospheric extension, allowing
melt to reach the surface. Volcanic anomalies are created by plate tectonics such as spreading plate boundaries or
subduction zones. The location of the volcanism is governed by the stress field in the plate and the amount of melt is governed by the fusibility of the mantle beneath. Plate tectonics can explain most of the volcanism on Earth. ==Active vs. passive plates==