martes, 25 de mayo de 2010

Chapter 9 (or 10): The Geological Record

Buenas Tardes!

My chapter was "On the Imperfection of the Geological Record," and I found an interesting quote I wanted to share: "In all cases positive paleontological evidence may be implicitly trusted; negative evidence is worthless, as experience has so often shown."
Unfortunately, this topic is a little hard to find news articles on, because most people are not looking into what the geological record does not show us (except creationists, etc). But there is all sorts of research going on right now based on what the geological record IS telling us-- mainly using it to predict various natural disasters, which could be helpful.
For example, researchers think that a second volcanic eruption will follow that of Eyjafjoll in Iceland, because that's what has happened the past 3 times Eyjafjoll went berserk. Katla, a volcano 25 miles away from Eyjafjoll, apparently tends to wake up when its sister volcano erupts, but with an impact orders of magnitude larger. So they're keeping an eye on thermal readings from satellites to see if this time it will follow the historical trend.
Additionally, earthquakes leave ample evidence in the geological record-- mainly in the form of turbidites, which are masses of coarse sediment that flow down underwater shelves and canyons during seismic disturbances, depositing layers of gravel and rock that indicate their high-energy origin. Scientists at Oregon State University have looked at the frequency of turbidites in offshore sediments to determine that the PAcific Northwest is due for a big earthquake-- 1 in 3 chance of a magnitude 9 in the next 50 years. Interestingly, the Midwest is also due for a massive earthquake (though turbidites can't be used for this sort of prediction, since it's in the middle of the continent, so they have to look for other types of geological evidence).



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