Waves of rockThis image was taken looking down on a beach in Okinawa. The rocks are interbedded sand
Waves of rockThis image was taken looking down on a beach in Okinawa. The rocks are interbedded sandstones (white layers) and shales (blue layers)The layers here are almost flat. The wavy patterns are the result of erosion; as the ocean crashes in, rocks erode in at different points in a complicated pattern. A viewer looking down on that pattern will then see a complex figure like this one created out of even flat-lying layers.Shales typically are colored due to a combination of the minerals present and the amount of organic material in them. Okinawa is made up mostly of sedimentary rocks that vary in age from the Mesozoic (up to 250 million years old) to the present. These rocks have been squeezed and thrusted upwards as well in order to reach the surface. The color in these rocks could be a result of some interesting combination of organic materials and minerals, or perhaps more likely it could be a result of some metamorphism. When rocks are metamorphosed in island-arc conditions, one of the terms for a phase assemblage produced is actually blueschist. Just guessing; these could be blueschist grade rocks.-JBBImage credit: https://www.flickr.com/photos/okinawa-soba/11019278586/(Creative commons)Read more:http://pubs.usgs.gov/fedgov/70039235/report.pdfhttp://www.dc.ogb.go.jp/hokudamu/e/summary.html -- source link
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