Rare-gas dating, II. Attempted uranium-helium dating of young volcanic rocks from the madeira archipelago

The 40Ar/39Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic)

“…Published radiometric age data focus on the younger volcanic rocks yielding K/Ar ages ranging from 0.7 to 3 Ma [ Watkins and Abdel‐Monem , 1971; Ferreira et al , 1975; Féraud et al , 1981; Mata et al , 1995] except for two from lava flows with ages of 3.9 Ma [ Ferreira et al , 1975] and 4.4 Ma (average of duplicate analyses from Mata et al [1995]). Ages and stratigraphic relationships of the oldest rocks (>3 Ma) are poorly understood.…”

U-Th/He Dating

“…From the 1950s to 1970s, studies of the mineral zircon and other materials such as corals, bone, and whole-rock volcanics continued intermittently but overall gave mixed results at best (Hurley 1954;Damon and Kulp 1957;Fanale and Kulp 1962;Fanale and Schaeffer 1965;Damon and Green 1963;Turekian et al 1970;Bender 1973;Leventhal 1975;Ferreira et al 1975).…”

Constant 4He Concentration and 190Pt‐4He age of Detrital Pt‐Alloy Grains from the Santiago River, Ecuador: Potential as a 4He Mineral Reference Material

“…Inherent variability in the U and Th mass fraction at the sample size typically used mean they cannot be used for determining He measurement procedures alone (Boyce andHodges 2001, Dobson et al 2008). Geological reference materials, such as the Columbia River basalt, USGS BCR-2 (Ferreira et al 1975) and the Knyahinya meteorite (Shultz and Franke 2004), have been developed as 4 He reference material but were never widely used. Natural Pt-alloy grains have potential as 4 He reference material because (i) the alpha particle-producing isotope ( 190 Pt) is homogeneously distributed within the mineral, which implies homogeneous distribution of the daughter 4 He (Shukolyukov et al 2011)…”