Curtin University | 2018 Aug 14
Curtin University researchers suggest Earth’s oldest known evolved rocks, which are four billion years old, were the result of asteroids slamming into the Earth’s crust and causing it to melt.
The research, published in Nature Geoscience today, found that Earth’s oldest evolved, or granitic, rocks, which form part of the Acasta Gneiss Complex in northwest Canada, have compositions that are distinct from those typical of Earth’s ancient continental crust. These differences suggest they formed through a different process.
Lead researcher Dr Tim Johnson, from the School of Earth and Planetary Sciences at Curtin University, said he and fellow researchers used modelling to show that the rocks were produced by partial melting of iron-rich hydrated basaltic rocks at very low pressures, equivalent to the uppermost few kilometres of the crust. ...
Meteorite Bombardment Likely Created Earth's Oldest Rocks
Goldchmidt Conference | 2018 Aug 14
An Impact Melt Origin for Earth’s Oldest Known Evolved Rocks ~ Tim E. Johnson et al
- Nature Geoscience (online 13 Aug 2018) DOI: 10.1038/s41561-018-0206-5