Oldest living tree in the world is only about 4,845 years old

Started Dec 27, 2012 | Discussions thread
Chato
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Oldest crystal on earth
In reply to PhilPreston3072, Dec 31, 2012

From the link...

Scientists have found a crystal believed to be at least 4.3 billion years old, making it the oldest known solid on Earth. And they say the crystal's sparkling facets contain hints that oceans, continents and perhaps even life itself developed much earlier than previously thought.

The grain of zircon, hardly wider than a human hair, was born in a molten fury not long after Earth formed. It was discovered inside younger stone in what is now Australia. "It represents a significant advance in reconstructing Earth's Dark Ages," said geologist Alex N. Halliday of the Swiss Federal Institute of Technology in Zurich. He was not involved in the research.

Zircon is a durable crystal made of silicon, oxygen and zirconium, among other elements. The oldest grain identified is one of a dozen very old crystals extracted from the Jack Hills section of northwestern Australia.

Two studies of the grains were conducted independently by international research teams. Their results were published in Thursday's issue of the journal Nature. One study reports that the oldest zircon is at least 4.3 billion years old. The second study puts its age at up to 4.4 billion years old. "We are pretty confident," said T. Mark Harrison, a UCLA geochemist and co-author of one of the studies. "Two studies conducted independently apparently have come to the same conclusion."

Both research teams dated the zircon grains by analyzing their isotopes of uranium. Uranium decays into lead. By calculating the ratio of uranium to lead, they determined that a dozen of the grains were very old indeed. Both teams used a high-resolution ion microprobe and a mass spectrometer to analyze the crystals.

Oldest crystal

Goodness, well, Phil was only off by four odd billion years...

Dave

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