Related Experiment Video
Updated: Aug 9, 2026

Atom Probe Tomography Analysis of Exsolved Mineral Phases
Published on: October 25, 2019
Cosmogenic He in terrestrial rocks: The summit lavas of Maui
1Isotope Laboratory, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093.
Abstract:
We have identified terrestrial cosmic rayproduced (3)He in three lava flows on the crest of Haleakala Volcano on Maui, 3 km above sea level, and approximately 0.5 million years old. Although these lavas, like all oceanic basalts, contain primordial (3)He from the mantle, the "cosmogenic" component ((3)He(C)) can be identified unambiguously because it is extractable only by high-temperature vacuum fusion. In contrast, a large fraction of the mantle helium resides in fluid inclusions and can be extracted by vacuum crushing, leaving a residual component with (3)He/(4)He ratios as high as 75x those in the atmosphere, which can be liberated by melting the crushed grains. Cosmogenic (3)He is present in both olivines and clinopyroxenes at 0.8-1.2 x 10(-12) ml(STP)/g and constitutes 75% +/- 5% of the total (3)He present. The observed (3)He(C) levels require a cosmic ray exposure age of only some 64,000 years, much less than the actual age of the lavas, if there is no erosion. Using a model that includes effects of uplift or submergence as well as erosion, we calculate an apparent "erosion rate" of the order of 8.5 m/10(6) years for the western rim of the summit crater, as an example of the application of measurements of cosmogenic rare gases to terrestrial geological problems.
More Related Videos
09:41Isolation of Quartz Grains for Optically Stimulated Luminescence (OSL) Dating of Quaternary Sediments for Paleoenvironmental Research
Published on: August 2, 2021
07:58Data Processing Methods for 3D Seismic Imaging of Subsurface Volcanoes: Applications to the Tarim Flood Basalt
Published on: August 7, 2017
Related Concept Videos
The Carbon Cycle
Radioactive Decay and Radiometric Dating
Sulfur Assimilation
Minerals
Mass Spectrometry: Isotope Effect
The Sulfur Cycle