The Oldest Meteorite Impact - Not Quite
A correspondent has sent me THIS LINK which concerns a meteorite impact in Western Australia. The "Science Alert" article is based on THIS ACADEMIC PAPER and is also the subject of
The burden of the article is that it refutes an earlier PAPER which claimed that the impact was the earliest known on Earth. The original dating was based on the very old age of the rocks in which cone structures were observed and an age for the impact of 3.47Ga.
The later paper tells us that, in the same area, shatter cones have been found in younger rocks aged at 2.77Ga and they conclude that the maximum age of the impact is 2.71Ga - and the minimum a meagre 0.4Ga.
These papers are examples of the scientific method at work. I also note that the article in THE CONVERSATION illustrates its argument about superposition by using a photograph of the Siccar Point unconformity - the earliest described unconformity. Do I detect someone poking fun at the competition!
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