...; detection limit 0.1 ppmv) by using two Fisons 8000-series Bench gas chromatographs. Helium (He) was also analyzed for these samples using a mass spectrometer (Varian Leak Detector; 10–4 atm cc/sec to 4 × 10–8 atm cc/sec). The statistical analysis of CO 2 and O 2 between the field and laboratory...

... of the cooling history from seven different field sites across the western Scottish Highlands using radiogenic apatite helium thermochronometry ([U-Th]/He; n = 14; ca. 31–363 Ma) and thermal modeling confirm that post-Caledonian heating and burial, as well as cooling and exhumation, must have been variable...

... chromatograph equipped with a TCD detector using He as carrier gas. The partial pressure of each gas species (CO 2 , N 2 , O 2 , Ar) was determined with reference to standards at different pressure. Helium partial pressures were determined by a leak detector (detection limit 0.00015 mbar) in a separate sample...

... , C.J. , 2006 , Seawater subduction controls the heavy noble gas composition of the mantle : Nature , v. 441 , p. 186 – 191 , doi:10.1038/nature04761. Jenden , P.D. , Hilton , D.R. , Kaplan , I.R. , and Craig , H. , 1993 , Abiogenic hydrocarbons and mantle helium in oil...

... Repository material. This study has shown that the basaltic magmas making up the Paraná-Etendeka CFBs were at least partly derived from a deep-seated upwelling mantle plume. A clear plume signature is preserved in olivine-rich dikes that have helium isotope ratios (>26 R A ) greater than those measured...

... volume estimates (i.e., gas to water volume ratios) match closed-system noble gas model predictions, suggesting that the Rotliegend system has remained isolated as a closed system since hydrocarbon formation. Radiogenic helium data show that fluid isolation occurred 63–129 m.y. after rock...

.... , and MacLean , N.J. , 2011 , Assessing the link between mantle source and sub-volcanic plumbing in the petrology of basalts from the 2001 and 2002/2003 eruptions of Mount Etna, Sicily: Evidence from geochemical and helium isotope data : Lithos , v. 123 , p. 254 – 261 , doi:10.1016/j.lithos.2010.11.013...

... in the extracts from these iron minerals were derived from a magmatic source. A striking aspect of the noble gas data is that He/Ne and He/Ar ratios are more than three orders of magnitude greater than those of air ( Fig. 17A ), which indicates that there is little or no atmospheric helium present in the samples...