oldest crust

Acasta gneiss at Yellowknife, Canada

Early Hadean crust: was that mafic, ocean-like or more felsic, closer to today continental crust? The point is, when and how plate tectonics (e.g., subduction and continental crust formation) began?

references:

> NATURE GEOSCIENCE | VOL 9 | OCTOBER 2016 | Changing of the plates, by Alan Brandon (Houston UH)

> Reimink, J., Davies, J., Chacko, T. et al. No evidence for Hadean continental crust within Earth’s oldest evolved rock unit. Nature Geosci 9, 777–780 (2016). http://sci-hub.tw/10.1038/ngeo2786