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Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

Nature

By:
, , , and
DOI: 10.1038/nature12992

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Abstract

Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents1. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot2. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone
Series title:
Nature
DOI:
10.1038/nature12992
Volume
506
Year Published:
2014
Language:
English
Publisher:
Macmillan Publishers Limited
Contributing office(s):
Volcano Science Center
Description:
4 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Nature
First page:
355
Last page:
358
Country:
United States
State:
Wyoming
Other Geospatial:
Yellowstone National Park
Online Only (Y/N):
N
Additional Online Files(Y/N):
N