Mantle He-3 and CO2 degassing in carbonic and geothermal springs of Colorado and implications for neotectonics of the Rocky Mountains

作者：Karlstrom Karl E^*; Crossey Laura J; Hilton David R; Barry Peter H

来源：Geology, 2013, 41(4): 495-498.

DOI：10.1130/G34007.1

Helium isotope (He-3/He-4) data from geothermal springs in the Colorado Rocky Mountains (western United States) provide unequivocal evidence for a remarkable mantle-to-groundwater connection, with contributions of up to 27% mantle-derived helium. Hydrochemical modeling of springs shows the mantle helium is associated with high pCO(2) with 76 +/- 20% of the CO2 also derived from endogenic (deep geologic) sources. These springs occur preferentially along faults, have highest He-3/He-4 values above domains of low mantle velocity, and demonstrate unexpectedly widespread neotectonic mantle degassing. Total CO2 flux through these springs is 3 x 10(8) mol/yr, a small but persistent contribution to the CO2 budget and an important baseline for carbon sequestration/leakage studies.

• 出版日期2013-4