Geology - In Australia, researchers have found diamonds, which are
more than four billion years old, making it only slightly younger than
the Earth itself as jewelry are not good are the microscopically small
stones. Nevertheless, they are very valuable for the research because
they allow conclusions about the early history of the earth.
Seven million years could be measuring wrong, but something like a
huge uncertainty, disappears in the face of the dimensions at issue
here: 4.252 billion years old are the diamonds, the researchers at the
University of Muenster have been excavated in Australia. "We have
worked with the diamond carbon, the oldest relic in hand," said the
mineralogist Thorsten Geisler. Carbon is a basic building block of
life.
Report their find Geisler and his collaborator Martina Menneken in the
British science journal "Nature" (vol. 448, p. 917). Although diamonds
can not be dated directly, but these pieces of jewelry from the early
history of the earth in the mineral zircon included. And the age of
zircons can be determined absolutely.
Few rocks of the earth's crust are older than 3.7 billion years and no
older than 4.03 billion years, the Australian geoscientists Ian
Williams writes in an accompanying article in "Nature". The accidental
discovery - actually investigate Geisler, and her team Menneken
zircons yes - because of its immense age is extremely important for
the study of Earth's history. "The earliest period of the planet's
history between the formation of Earth 4.5 billion years ago and the
formation of the oldest known rocks 500 million years later, the
geological equivalent of the Middle Ages," writes Williams.
And this middle age, geologists argue violently. The young Earth
cooled quickly, so that could make rocks (and later also the first
life) faster than thought? "It is possible that the cooling of the
earth and thus the formation of a solid crust began much earlier than
previously thought," said Geisler. Could have developed so that the
continents and the first life on the once barren earth sooner than
previously thought. The oldest known diamonds found were dated to an
age of about 3.3 billion years ago.
The opposite is also conceivable. With an analysis of traces of
nitrogen in the artefacts will now be examined whether the diamonds
but only relatively short time under high pressure in the mantle or
spent relatively long but came under reduced pressure before they were
trapped in zircon.
Curated by Martin Geisler Young Scientist Menneken is only 25 years
old. She had studied zircon inclusions in the Australian sediments.
Almost by chance, she found in 45 of 1000 analyzed zircons eventually
the diamond crystals. However, they are large only between 10 and 60
microns - too small to detect by the human eye and only under the
microscope.
