Geology
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Going Underground
Asteroid & Meteorite Impact Sites
Two of the solar system's best natural timekeepers have been caught misbehaving, suggesting that the accepted ages for the oldest known rock samples are off by a million years or more. According to two new studies, a radioactive version of the element samarium decays much more quickly than previously thought, and different versions of uranium don't always appear in the same relative quantities in earthly rocks. Both elements are used by geologists to date rocks and chart the history of events on our planet and in the solar system.
Age of oldest rocks off by millions of years - space - 29 March 2012
This web page contains the following sections: Agates are semi-precious gemstones that are a variegated form of chalcedony (pronounced kal-sed'-nee), which is silicon dioxide in the form of microscopic fibrous quartz crystals.
Agate Basics
Volcanoes & Earthquakes
Natural History Museum, London - Fossil Dept
Fossil Folklore From ammonites to sharks' teeth, explore myths about fossils from all over the world and find out the facts behind the stories.
