Grand Canyon GigaView #20 - Blacktail Canyon
The Great Unconformity - Welcome to the surface of the Earth, approx. 550 million years ago. The first layer of rock, at ground level here, is called the Vishnu Schist. It consists of several complex sets of sedimentary and volcanic that were laid down 1.8 billion years ago, but were buried and metamorphized into schist and gneiss about 400 million years later.
By 550 million years ago, the Vishnu Schist was exposed as a flat, rocky plain that was inundated by the sea. The upper, layered rock is the Tapeats Sandstone and is made of beach sand. The Tapeats begins the sequential series of deposition that ends at the top of "The Grand Staircase" of the American Southwest.
What happened in the 1.2 billion years of Earth's history between the deposition of this basement rock layer and its final exposure is still unknown to science. One thing that is known is that life came to Earth. There is no evidence of fossils or trace of bacterial colonies in the PreCambrian schist and gneiss, but the Tapeats Sandstone and the layers above it show the rich tapestry of evolution through a fairly continuous fossil record.
Grand Canyon GigaView is a new school virtual tour of the Grand Canyon created with a collection of spherical GigaPan images taken on a private rafting trip in April 2010 and geolocated in Google Earth, Bing Maps, and 360Cities. Explore the journey http://grandcanyongigaview.tumblr.com/
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The Northeast region is where it all started. Thirteen British colonies fought the American Revolution from here and won their independence in the first successful colonial rebellion in history. Take a look at these rolling hills carpeted with foliage along the Hudson river here, north of New York City.
The American south is known for its polite people and slow pace of life. Probably they move slowly because it's so hot. Southerners tend not to trust people from "up north" because they talk too fast. Here's a cemetery in Georgia where you can find graves of soldiers from the Civil War.
The West Coast is sort of like another country that exists to make the east coast jealous. California is full of nothing but grizzly old miners digging for gold, a few gangster rappers, and then actors. That is to say, the West Coast functions as the imagination of the US, like a weird little brother who teases everybody then gets famous for making freaky art.
The central part of the country is flat farmland all the way over to the Rocky Mountains. Up in the northwest corner you can find creative people in places like Portland and Seatle, along with awesome snowboarding and good beer.
Text by Steve Smith.