Standing in the blazing sun of the eastern Arizona desert, you would not suspect that 200 million years ago towering sequoias nearly 200 feet tall and 9 feet in diameter grew here in lush forests among broad rivers.
The evidence of this vanished ecosystem, of course, lies scattered on the ground—the fossilized trunks of these trees that give the name to Petrified Forest National Park.
Over the millennia, climates changed, shallow seas covered the region, depositing marine sediments and burying the fossil forest deeper until about 60 million years ago when tectonic forces pushed upward the entire area we call the Colorado Plateau. Erosion followed, stripping off the younger sedimentary layers and eventually bringing the fossil forest to once more to light.
More information here.
http://www.nps.gov/pefo/naturescience/fossils.htm
P.S., In addition to the plants, this Late Triassic ecosystem supported insects, amphibians, and reptiles, including crocodile-like phytosaurs and Coelophysis, an early dinosaur.
No comments:
Post a Comment