[Rockhounds] The New Historian of the Smash That Made the Himalayas

[Kreigh Tomaszewski]

Earth is unique in plenty of ways. But Lucía Pérez-Díaz
<https://www.earth.ox.ac.uk/people/lucia-perez-diaz/>, a geologist at the
University of Oxford, reckons that one of its most stunning novelties is
its ability to constantly change its face.

Our planet’s ever-metamorphosing veneer is made up of colossal slabs of
rock named tectonic plates: wafers of crust stuck atop Earth’s upper
mantle. They drift around at roughly the rate your nails grow, crashing
into one another, slipping alongside each other, overrunning and diving
below each other, and splitting apart.

We don’t know how plate tectonics got going
<https://www.quantamagazine.org/plate-tectonics-may-be-essential-for-life-20180607/>,
nor do we have a clear picture of the structures beneath the surface that shift
those plates around
<https://www.quantamagazine.org/continents-of-the-underworld-come-into-focus-20200107/>.
But a mere half-century since the theory of plate tectonics first came
together, it is clear that this patient process is both omnipotent and
omnipresent. It is the narrative arc that ties every episode of Earth’s
geologic history together.

Thanks to the magnetic compasses hidden in volcanic rocks ancient and new,
scientists know where each tectonic jigsaw piece has been over eons of
time. They can replicate the plates’ odysseys in beautiful and
breathtakingly precise simulations that reveal the destruction and creation
of Earth’s many faces
<https://www.nytimes.com/2021/02/06/science/tectonic-plates-continental-drift.html>
.

But these exercises in tectonic time travel bring up something strange:
Around 67 million years ago, the Indian microcontinent — which ultimately
headed north and collided with Eurasia to make the Himalayas — really
picked up speed. It’s as if other tectonic plates were ambling about, then
India strapped on a jetpack.

Like many, Pérez-Díaz thought India’s behavior was peculiar. Some of her
contemporaries came up with a seemingly agreeable explanation, but she
remained suspicious and dug deeper. Her work, published last year in the
journal *Geology*
<https://pubs.geoscienceworld.org/gsa/geology/article/48/12/1169/588493/Indo-Atlantic-plate-accelerations-around-the>,
concludes that India’s dramatic acceleration, one of the most monumental
moments in plate tectonics in the past 100 million years, is effectively an
illusion caused by a broken clock.
https://www.quantamagazine.org/the-new-historian-of-the-smash-that-made-the-himalayas-20210414/