Quaternary volcanoes in New Britain, PNG offer remarkable and unique insights into the nature of subduction zone processes. In this single location, eruptions have built a chain of well-developed islands behind the arc, tapping parts of the mantle wedge normally unavailable for study. In addition, volcanoes along the arc front erupt some of the most elementally depleted arc rocks known, offering an excellent opportunity to investigate the nature and composition of slab-derived fluxes.
In 1970s the Australian Bureau of Mineral Resources conducted an intensive mapping and sampling program throughout PNG, aimed at achieving a better understanding of some of the volcanological hazards in this area. One lasting legacy of this program is a sample collection comprising ~1200 volcanic rocks from many volcanoes and associated maps providing a survey of the region's volcanoes that is incomparable in its scope with any other such effort worldwide.
A major new research program based upon this valuable resource has begun.
In addition we have a variety of other continuing projects based upon the Mariana and Tonga-Kermadec-Lau subduction systems.
Some recent contributions:
Woodhead, J.D., Stern, R.J., Pearce, J.A., Hergt, J.M. & Vervoort, J (2012) Hf-Nd isotope variation in Mariana Trough basalts: the importance of ‘ambient mantle’ in the interpretation of subduction zone magmas. Geology, in press.
Woodhead, J.D., Hergt, J.M., Greig, A & Edwards, L (2011) Subduction zone Hf-anomalies: mantle messenger, melting artifact or crustal process? Earth. PLanet. Sci. Lett. in press.
Timm, C., Graham, I.J., de Ronde, C.E.J., Leybourne, M.I. and Woodhead, J (2011) Geochmical evolution of Monowai volcanic center: new isights into the northern Kermadec arc subduction system, SW Pacific. Geochemistry Geophysics Geosystems 12, Q0AF01, doi:10.1029/2011GC003654.
Todd, E., Gill, J.B., Wusoczanski, R.J., Hergt, J., Wright, I.C., Leybourne, M.I. & Mortimer, N. (2011) Hf isotopic evidence for small-scale heterogeneity in the mode of mantle wedge enrichment: Southern Havre Trough and Suth Fiji Basin back arcs. Geochemistry, Geophysics, Geosystems 12, Q09011, doi:10.1029/2011GC003683.
Woodhead, J.D., Hergt, J., Sandiford, M & Johnson, R.W. (2010) The big crunch: physical and chemical expressions of arc/continent collision in the western Bismarck arc. J. Volcanology and Geothermal Research 190, 11-24.
Hergt, J.M & Woodhead, J.D. (2007) A critical evaluation of recent models for Lau-Tonga arc-backarc basin magmatic evolution. Chemical Geology , 245, 9-44.
Woodhead, J & Brauns, M (2004) Current limitations to the understanding of Re-Os behaviour in subduction systems, with an example from New Britain. Earth and Planetary Science Letters 221, 309-323.
Woodhead, J.D., Hergt, J.M., Davidson, J.P. & Eggins, S.M. (2001) Hafnium isotope evidence for ‘conservative’ element mobility during subduction zone processes. Earth and Planetary Science Letters 192, 331-346.
