FROM THE FIELD
The Dawn of Plate Tectonics
An ancient grain of zircon found
In Jack Hill sandstone north of Perth,
Inside its crystal lattice bound:
Secrets of our planet’s birth.
The oldest grain (we rock hounds swoon),
Tells of magma oceans past,
An early impact yields the moon;
And all of this occurred so fast!
The zircon’s old, which then implies
That solid rocks must be still older.
In Canada, a sequence lies,
With implications even bolder!
A pattern locked within old lava
Echoes patterns from the deep;
Mariana-like subduction …
To plate tectonics, take the leap!
Hadean times are cloaked in intrigue,
Eons distant, full of strife,
Yet it seems these rocks held promise,
Full of boron, primed for life!
In the news:
New Record for Oldest Earth Rock, Sky and Telescope
Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography, Nature Geoscience
The Dawn of Plate Tectonics, Science Now
Heading down early on? Start of subduction on Earth, Geology