Plume-like neon in a metasomatic apatite from the Australian lithospheric mantle

Recycled noble gas and nitrogen in the subcontinental lithospheric mantle: Implications from N-He-Ar in fluid inclusions of SE Australian xenoliths.

“…Noble gases in ultramafic rocks (=xenoliths and orogenic peridotites) are mostly trapped in confined fluid inclusions. These are probably metasomatic fluids infiltrated through the mantle wall rock and their helium isotopic signatures clearly indicate mantle origin (Matsumoto et al, 1997(Matsumoto et al, , 1998(Matsumoto et al, , 2000(Matsumoto et al, , 2001. As will be shown later in this paper, Matsumoto et al (2001) found a clear correlation between primordial 3 He and atmospheric 36 Ar in former mantle wedge rocks, indicating that source for the metasomatic fluids should also have air-Ar in the…”

“…Several studies have shown evidence of MORB-type noble gases in the Australian SCLM (Porcelli et al, 1986;Matsumoto et al, 1997Matsumoto et al, , 1998Matsumoto et al, , 2000. The MORB-type component is confirmed by our helium analyses (Table 1), which show a remarkably uniform 3 He/ 4 He ratio of 10.1 ± 0.2 × 10 -6 , that is within the range of the upper mantle helium isotopic ratio measured in MORBs (e.g., Craig and Lupton, 1981 (Marty, 1995 (Marty, 1995 Sano et al, 1998). tle and the atmosphere is not sufficient to explain the variable nitrogen isotopic ratios observed in the Australian xenoliths.…”

Low solubility of He and Ar in carbonatitic liquids: Implications for decoupling noble gas and lithophile isotope systems

“…Metasomatic agents have also been invoked to explain apparent decoupling between noble gases and lithophile element isotope systematics in numerous other 'plume' settings (Kerguelen (Valbracht et al, 1996a); Samoa (Farley et al, 1992); Easter Island (Poreda et al, 1993); Cameroon (Barfod et al, 1997); in continental rift settings (e.g. (Matsumoto et al, 1997;Porcelli et al, 1986)), in subduction related massifs (Horroman (Matsumoto et al, 2001)), and even during generation of MORBs (Red Sea (Trieloff et al, 1997)). …”

Nd, Sr and Os isotope systematics in young, fertile spinel peridotite xenoliths from northern Queensland, Australia: A unique view of depleted MORB mantle?

“…Upper mantle derived xenoliths are abundant in many of the lava-flow provinces (e.g., O'Reilly, 1989). Peridotite xenoliths from southeastern Australia in particular have been well documented, providing insights into lithosphere age, structure, stabilisation and modification processes (e.g., Frey and Green, 1974;McDonough and McCulloch, 1987;Griffin et al, 1988;O'Reilly and Griffin, 1988;Yaxley et al, 1991;McBride et al, 1996;Handler et al, 1997;Matsumoto et al, 1997). Both whole rock and sulfide Os isotopic analyses of southeast Australian xenoliths suggest a dominantly Proterozoic CLM Alard et al, 2002).…”