Pieces of Africa in Alabama and Georgia? Since the theory of plate tectonics was developed, geologis

Pieces of Africa in Alabama and Georgia?Since the theory of plate tectonics was developed, geologists have realized that continents often run into each other and split apart. We can even see this in modern day mountain ranges like the Himalayas, where crust that came from Asia and crust that came from India are crashing into each other causing the crust to buckle and pile on top of each other.Africa and North America did something similar 300 million years ago to form Pangaea, but when those continents split apart (http://on.fb.me/1wjwW7X), they didn’t split exactly in the place where they came together. Some pieces of Africa stuck to North America, and it’s been proposed that one of these slivers currently sits in Alabama and Georgia. There is something odd about the crust in this area, but the real tough question is, how do you prove something used to be part of Africa when Africa is now an ocean away?The slivers of rock are located near a fissure of measurably lower-than-normal magnetism called the Brunswick Magnetic Anomaly (BMA). The rock of the BMA is 14 to 20 kilometers (9 – 12 miles) below the surface. It runs through Alabama and Georgia, and just off the coast of South and North Carolina. The unusual magnetism acts as a fingerprint to help geologist determine how the BMA rocks formed.Two different hypotheses exist to explain the BMA formation. The first eypothesizes thaht the BMA is a fissure of 200 million year old volcanic rock where North America first pulled away from Pangaea. This hypothesis suggests that the continents started to split apart at the BMA, but eventually separated instead at a weaker point further east into the African continental crust, causing part of Africa to stay with North America. The second hypothesis is that the BMA is the 300 million year old collision point of North America and Africa when Pangaea formed, meaning part of the collision point itself and some of the surrounding rocks from Africa, ended up in Alabama and Georgia.Regardless of which theory proves to be correct, the end result is that part of the continental crust that makes up Alabama and Georgia, used to be part of the continental crust of what is now Africa.REImage Credit: Massios PietrobanPhoto Credit: “Whole world - land and oceans 12000” by NASA/Goddard Space Flight Center – NASAhttp://en.wikipedia.org/wiki/Earth_observation_satellite#mediaviewer/File:Whole_world_-_land_and_oceans_12000.jpgRead More:http://www.geosociety.org/news/pr/2014/14-22.htmhttp://www.geologyin.com/2014/12/piece-of-africa-found-under-alabama.htmlhttp://news.discovery.com/earth/rocks-fossils/piece-of-africa-found-under-alabama-140422.htm -- source link
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