[Rockhounds] Mysterious 165-Million-Year-Old Minerals Found on Easter Island Defy Plate Tectonics

[Kreigh Tomaszewski]

Easter Island consists of several extinct volcanoes. The oldest lava
deposits formed some 2.5 million years ago on top of an oceanic plate not
much older than the volcanoes themselves. In 2019, a team of Cuban and
Colombian geologists left for Easter Island to accurately date the volcanic
island. To do so, they resorted to a tried-and-tested recipe: dating zircon
minerals. When magma cools, these minerals crystallize. They contain a bit
of uranium, which ‘turns’ into lead through radioactive decay.

Because we know how fast that process happens, we can measure how long ago
those minerals formed. The team from Colombia’s Universidad de Los Andes,
led by Cuban geologist Yamirka Rojas-Agramonte, therefore went in search of
those minerals. Rojas-Agramonte, now at the Christian Albrechts-University
Kiel, found hundreds of them. But surprisingly, not only from 2.5 million
years old, but also from much further back in time, up to 165 million years
ago. How could that be?

https://scitechdaily.com/mysterious-165-million-year-old-minerals-found-on-easter-island-defy-plate-tectonics/