Researchers working in Western Australia have discovered the oldest fragments of the Earth’s early crust that have yet been identified: microdiamonds. These microscopic crystals measure only 50 microns across and were formed 4.2 billion years ago. This discovery sheds light on how long it took for the Earth’s crust to form, since this date is only 300 million years after the formation of the Earth itself.
Summary
Western Australian researchers have discovered microdiamonds, the oldest fragments of the Earth’s early crust yet identified. These microscopic crystals were formed 4.2 billion years ago, only 300 million years after the formation of the Earth itself. This discovery sheds light on how long it took for Earth’s crust to form.
Notable Valid Inferences
Earth’s crust did not take longer than 300 million years to begin to form.
A
The Earth’s crust took no longer than 300 million years to start to form.
Must be true. We know this because the microdiamonds researchers found were part of the Earth’s early crust. If the microdiamonds existed 300 million years after Earth itself was formed, then Earth’s crust must have taken no longer than 300 million years to begin to form.
B
The Earth’s crust first formed in the area that is now Western Australia.
Could be false. To claim this is where the Earth’s crust first formed is too extreme. We only know that the microdiamonds the researchers found are the oldest fragments to be found to date. It is possible there exists older fragments that have not yet been found.
C
The Earth’s crust took billions of years to form.
Must be false. We know the microdiamonds the researchers found were part of Earth’s early crust, and these existed only 300 million years after the formation of Earth.
D
Microdiamonds were the first components of the Earth’s crust to form.
Could be false. To claim microdiamonds were the first components is too extreme. We only know that they are the oldest fragments identified to date. It is possible that older fragments exist that have not yet been identified.
E
All naturally occurring microdiamonds were formed at the time the Earth’s crust was being formed.
Could be false. To claim all microdiamonds were formed at this time is too extreme. It is possible that there are other naturally occurring microdiamonds that formed after the ones the researchers identified.