What Triggered an Ancient Magma Surge in the North Cascades?
A new, high-precision timeline helps clarify the story of a 79-million-year-old flare-up.
In the North Cascades region, an ancient magma surge occurred between 79 million and 60 million years ago, lasting for tens of millions of years. This high-volume, high-precision event was analyzed by Karmakar et al. through rock samples and geochemical measurements. The surge was linked to the thickening of the continental crust, which is typical for such flare-ups.
However, it was unclear whether the thickening caused the flare-up or was a result of it. Through careful examination and geochronology, the researchers determined that crustal thickening did not begin until after the flare-up started. Both the flare-up and an earlier one, from 96 million to 86 million years ago, shared similar spatial and temporal correlations in magma flow and crustal thickness.
Written by urgent.news from Eos's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
