Petrified Forest National Park, AZ
Sept 11, 1998
Forecast
Petrified Forest National Park, AZSept 11, 1998 |
Forecast |
Since plants made the adaptation to land before any animals, we thought we'd start our Natural History Tour studying some of the oldest plants, petrified trees. It was pretty cool to see stone that was once a tree. Links: (See below for resources you can buy online)
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The trees in Petrified Forest National Park are about 200 million years old, in the late Triassic period. The trees were carried to the prehistoric park by rivers. There were so many logs that they jammed up the river. Then they got buried by sand, volcanic ash and mud. The rivers flowed over them, dissolving the silica in the ash into the water. The silica seeped into the logs and crystallized cell by cell. Millions of years later, they got pushed up when the Colorado Plateau was uplifted. Wind and water eroded the soil and parts of the logs were exposed. |
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Here's a picture of a knot in a log. A knot is a place in the tree where a branch was. None of the petrified trees have any brances. Scientists think that the branches were broken off when the trees were carried downstream by the ancient river. |
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Harrison counts the rings of one log, and estimates it to be at least 22 years old. It is probably older than that, because the outer layers were rubbed off as the log floated down the river. |
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There were lots of smaller fragments that looked more like wood chips or stone. When polished they are very pretty. |
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We learned that about one ton (2000 lbs) of fragments are removed from the park every month! Yikes! The Park is for everyone to enjoy, not to take home. Don't take the park home! |
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On 6/15/99, Susan asks: I am looking for information on fern trees. My father has a lot of pieces of a fern tree that a man at Indiana University told him was 100 to 200 million years old. I have live in Bloomington Indiana and have never heard of anyone finding such a thing down here,but my father has quite of few pieces of it and keeps finding more. If you could provide any information on prehistoric fern trees or if you know of someone who might I would appericate any information I can get. Answer: An interesting side note is that nearly all of the world's coal is the remains of these great Carboniferous Era forests, created 300 million years ago! |
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