The secrets of early Earth lie in a bright red crystal no larger than a dust mite.
A group of scientists claim to have dated a 400-micrometer zircon crystal to about 4.4 billion years ago — a discovery that could help scientists understand the geological conditions of early Earth.
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The crystal was found in a region north of Perth, Australia known as the Jack Hills in 2001, Reuters reported. The scientists published their findings in the science journal Nature Geoscience on Feb. 23; in the publication, Valley and his team explained their use of a technique called atom-probe tomography to date the crystal. The technique allows scientists to image and assess single atoms of lead to determine the age of a rock with increased accuracy.
Earth is thought to be around 4.54 billion years old, but according to fossil records, no evidence of life has been found prior to 3.5 billion years ago. Even the oldest rocks before this discovery were about 3.8 million years old. This gap in rock formations and life accounts for about 600 million years during which scientists knew very little about the state of early Earth. Still, it's often thought to have been "hell-like" with a magma ocean, according to John Valley, a professor in the Department of Geoscience at the University of Wisconsin-Madison, who led the group of scientists.
Evidence like this zircon crystal suggests that the Earth cooled to form the planet's crust earlier than previous rock evidence has suggested, within the first 100 to 200 million years. In that cooling process, steam from the atmosphere would have condensed to create oceans. If oceans were present, it could've been possible that microbial life also existed, Valley told Reuters — a wildly different portrait of our planet than a nightmarish, lava-covered Earth.
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