Study released today on Yellowstone helium: [link to www.nature.com]
The scientists who revealed today’s information report the quantity of helium-4 in Yellowstone’s gas emissions is hundreds to thousands of times greater than it should be — a sign that the crust is releasing its ancient stores of the rare isotope, the researchers said.”However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by decay of uranium and thorium. Today’s report shows 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.” This means the Helium -4 is coming from very far beneath the ground, a clear signal that something big is happening that hasn’t happened in Yellowstone in our lifetime.
Things began to change roughly 2 million years ago, however, when hot magma intruded on the crustal system from below and triggered several enormous volcanic eruptions, the most recent about 640,000 years ago.
"This really isn't a volcano story," Lowenstern said. "But it reveals how the Earth's crust behaves on a long time frame. The crust 'holds its breath' for long periods of time, and then releases it during tectonically and volcanically active bursts."
reply to post by Olivine
yes and no.....
The crust 'holds its breath' for long periods of time, and then releases it during tectonically and volcanically active bursts."
so if the levels of helium4 is increasing now ( after 650.000 years heating up) than its now increasing activity tectonic and volcanic
edit on 23-2-2014 by ressiv because: (no reason given)edit on 23-2-2014 by ressiv because: (no reason given)
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.