caa a22 4500 465791425 CHVBK 20180323112025.0 cr unu---uuuuu 170327e19901101xx s 000 0 eng 10.1007/BF00306531 doi (NATIONALLICENCE)springer-10.1007/BF00306531 Meta-igneous granulite xenoliths from Mount Ruapehu, New Zealand: Fragments of altered oceanic crust? [Elektronische Daten] [Ian Graham, Peter Blattner, Malcolm McCulloch] Meta-igneous granulite (MIG) xenoliths in lavas from Mount Ruapehu, Taupo Volcanic Zone, New Zealand, have variable but relatively high δ18O (+8.2 to +11.7) and 87Sr/86Sr (0.70506 to 0.70872), and εNd ranging from +1.5 to +6.2. They show a strong positive correlation between 87Sr/86Sr and δ18O, both of which are also broadly correlated with Mg number, but lack any correlation between 87Sr/86Sr and εNd. The xenoliths have been mineralogically re-equilibrated at lower-crustal temperatures (800-930°C) and pressures (7-10 kbar). Geochemical and isotopic evidence suggests they are fragments of oceanic crust that have been altered previously in an ocean floor hydrothermal system. Alternatively, they may be igneous rocks of unknown origin hydrothermally altered in the lower crust. Irrespective of this uncertainty, the xenoliths provide rare samples of the lower crustal basement beneath Taupo Volcanic Zone and represent a potential source rock for the voluminous rhyolites and ignimbrites that dominate the zone. Springer-Verlag, 1990 Graham Ian Institute of Nuclear Sciences, Lower Hutt, New Zealand aut Blattner Peter Institute of Nuclear Sciences, Lower Hutt, New Zealand aut McCulloch Malcolm Research School of Earth Sciences, Australian National University, Canberra, Australia aut Contributions to Mineralogy and Petrology Springer-Verlag 105/6(1990-11-01), 650-661 0010-7999 105:6<650 1990 105 410 https://doi.org/10.1007/BF00306531 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00306531 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Graham Ian Institute of Nuclear Sciences, Lower Hutt, New Zealand aut NATIONALLICENCE 700 1- Blattner Peter Institute of Nuclear Sciences, Lower Hutt, New Zealand aut NATIONALLICENCE 700 1- McCulloch Malcolm Research School of Earth Sciences, Australian National University, Canberra, Australia aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 105/6(1990-11-01), 650-661 0010-7999 105:6<650 1990 105 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer