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When I studied earth science, a lecturer mentioned that one of the anomalies that earth science hasn’t been able to explain, is a piece of crust in the USA.

This piece of crust appeared to match very well the crust of another continent, if turned upside down, and didn’t match the surrounding crust in the USA.

I cant find information about this and i can't forget about it. Is there any basis for this claim?

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Did he mention in what part of the US. –  Spießbürger May 5 at 9:59
    
really sorry, cant remember, although i think he did mention it. i got the impression he was aware of only 1 such anomaly. Also I cant remember the location of the matching crust, MAYBE Africa but im really not sure. –  wandera May 5 at 10:02
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Could be the remainder of a nappe. If the top part erodes only a piece of upside down crust could be left over, which seems to have no direct relation to the surrounding rock. –  hugovdberg May 5 at 10:19
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It could also be an ophiolite, although I don't think there are any examples of these being truly upside down although they might initially appear to be so due to a fold (eg. Troodos in Cyprus - where the higher elevations represent the upper mantle) –  winwaed May 5 at 12:54

1 Answer 1

Most probably, he was referring to the Brunswick Magnetic Anomaly: http://www.geosociety.org/news/pr/2014/14-22.htm

This is an area of lower-than-normal magnetism present in North America in the Southwestern United States. Note that altough it COULD be a piece of Africa, it could also be caused by something else.

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My lecturer made a point of it being upside down. I want to point out that lecturers have their opinion and do employ 'lecturers license'. I realize that this answer may be what he was referring to. But I cant be sure because of his assertion about it being upside down. –  wandera May 5 at 14:48

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