深地地图揭示美国失落大陆碎片

Sensor array traces how rocks conduct electricity, revealing mineral riches, crust that can amplify solar storms, and fragments of ancient landmasses A long the eastern front of the Appalachian Mountains, buried just below the sur- face, lies a fragment of a lost continent. Running from Maine to Georgia, the 200-kilometer-thick slab of crust was probably created by vol- canic eruptions during the breakup of the Pangaea supercontinent some 200 million years ago and later bur- ied by silt from eroding mountains. Known as the Piedmont Resistor, this piece of Pangaea is one of the signature discoveries of the Magneto- telluric (MT) Array, 1800 temporary stations scattered across the contigu- ous United States that measured the conductivity of deep rocks. …