Professor Richard Arculus

BSc (University of Durham UK),
PhD (University of Durham UK), (FAusIMM),
- Fellow of the Australian Institute of Mining and Metallurgy

Office Location
Room 104, DEMS Building 47

Mailing Address
Department of Earth and Marine Sciences
DEMS Building 047
Australian National University
ACT 0200 Australia

Telephone +61 2 612 53778

Fax +61 2 612 55544

Email Richard.Arculus@anu.edu.au

Research Interests

My primary interest is the differentiation of the Earth, particularly the formation of the continental crust and global geochemical recycling. I pursue this through the study of island and back arc magmatism, and the geochemical changes accompanying subduction of crustal materials. More recently, I have been concentrating on volatile losses from magmas in arc settings and other environments, and studying the formation of oceanic plateaus.

Research Projects

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Submarine arc-backarc magmatism in the Papua New Guinea (PNG) - Solomons -Vanuatu region

There are two main reasons for resorting to ship-based sampling of the products of arc and backarc magmatism. The first of these is the fact that glass is more commonly preserved in lavas that are quenched in water, and this material is essential for tracking the processes of magmatic evolution. The second is that detailed analysis and quantification of the fluxes of gases in the arc-backarc environment is only really practicable in the submarine realm, where the gases are trapped in the water column. Accordingly, I have been collaborating with colleagues from the Division of Exploration & Mining of CSIRO (North Ryde, Sydney) in the use of the RV Franklin in cruises to the SW Pacific. We have successfully recovered spectacular suites of young, glassy volcanic rocks in the past two years, and discovered newly active backarc spreading centers in the Coriolis Troughs of Vanuatu. In 2002, we have two cruises scheduled for the Bismarck (PNG) and San Cristobal (between the Solomons and Vanuatu) arcs.

Asama volcano in central Honshu, Japan.

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Arc magmatism in a region of ridge subduction

It is the fate of all ridges to be subducted, but there are a limited number of examples of this phenomenon occurring at any one time. One of the active examples is in the Solomon Islands, where the Woodlark Ridge is being subducted eastwards beneath the New Georgia Group of volcanoes. A remarkable array of lava types has been erupted in the Pliocene to Recent from these volcanoes, including highly magnesian picrites, andesites, and dacites. We are obtaining comprehensive geochemical analyses of these rocks, determining their ages, and attempting to model the particular processes of magma generation and evolution associated with ridge subduction.

RV Franklin

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The deep petrologic structure of island arcs

It is a fact that deep structures of island arcs are rarely exposed (exceptions include the Horoman Complex in Hokkaido, and the Jijal Complex in the Himalayas). Despite the consensus that island arc magmatism is critical in formation of the continental crust, we are ignorant of much of the plutonic processes accompanying the more accessible volcanic products. We can predict that considerable quantities of ultramafic and mafic cumulate complements to the erupted basalt-andesite-dacite arc suites must exist. While there are several explanations for the apparent lack of these complements, there are some fortuitously exposed examples in the South Island of New Zealand where the magmatic processes in the roots of arc volcanoes can be studied. Over the past few years, we have been examining a number of layered, ultramafic-mafic-intermediate plutonic complexes of Permo-Triassic age in the so-called "Median Tectonic Zone" (or Batholith) stretching from Bluff in the south to Nelson in the north of the South Island. Of particular interest has been the discovery of in-situ platinum group minerals in ordinary arc tholeiite magmas, and the recognition of complex cumulate – percolating magma interactions in the plutonic sequences.

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The deep petrologic structure of oceanic plateaus

Mantle plumes are ephemeral, and are accompanied on first ascent into the outer regions of the Earth by extensive partial melting – the magmatic products form over-thickened portions of crust known as oceanic plateaus, and the largest current example is the Ontong Java Plateau (OJP) in the SW Pacific. The OJP collided with the Solomons – Vanuatu arc system about 10 million years ago, triggering a reversal in subduction polarity. Following the collision, the margin of the Plateau was locally uplifted in the NE Solomon Islands of Malaita and Santa Isabel. Associated with extensive outcrops of basaltic pillow lavas of the OJP are gabbros and peridotites (also exposed on the island of Choiseul) that seem to be the plutonic equivalents and residual mantle fraction respectively of the erupted magmas. We are studying the genesis of these rocks.

Asama volcano in central Honshu, Japan.

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Isolating the variables – the multicomponent sources of arc-backarc magmas

The processes of magma formation in arc-backarc systems are complex involving components from the subducted lithosphere (i.e., metamorphosed sedimentary, igneous and residual mantle lithologies), advecting mantle wedge, and the overriding arc lithosphere. Because there can be considerable ambiguity in the identification of these components and the individual mass fluxes involved, it is important to find natural locations where the component inputs vary. For example, we identified a region of northern Honshu where the active volcanic chain associated with subduction of the Pacific Plate transgresses a major terrane boundary in the arc lithosphere, and showed that a distinct change in the Pb isotopic character of the arc magmas is coincident with this boundary. The importance of this observation is that the budget of Pb in arc magmas is commonly asserted to be controlled by a subducted lithosphere component. But clearly, our models have to become more sophisticated in terms of the mass balances of the different components involved. We have recently extended this type of research effort to a transect along the volcanic front from Hokkaido (Japan) to the southern Kurile Islands (Russia), once again crossing a major lithospheric terrane boundary while the nature of the subducted Pacific Plate is constant.

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The geochemical and petrologic changes accompanying high pressure/temperature subduction zone metamorphism

There is clear geochemical and isotopic evidence that some fraction of subducted lithosphere is returned to the Earth's surface, both in arc-backarc magmas and also as exhumed terranes in former plate collision zones. Our current knowledge of the geochemical changes that occur over a range of pressures and temperatures in subducted lithologies is not however, particularly sophisticated. We have been studying the details of these changes in suites of blueschist-eclogite rock types, particularly from Ecuador and New Caledonia. Our aims are to map with laser ablation inductively coupled plasma source mass spectrometry (LA-ICP-MS) the detailed trace element distributions in the various mineral phases comprising these rock types. We are trying to assess what fraction of the highly mobile trace elements such as U, Pb, and Sr (characteristically "over-enriched" in arc magmas) are lost at the various stages of prograde metamorphic evolution of subducting lithosphere.

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The petrologic and geochemical evolution of the Rabaul Volcano (PNG)

In 1994, twin volcanic cones either side of the Rabaul caldera (i.e., harbour) erupted in spectacular fashion, causing considerable dislocation to the human population. Eruptions continue from the eastern vent (Tavurvur) while the western vent (Vulcan) is now dormant. This is merely the latest eruption episode of a complex basalt-andesite-dacite volcano. Because of the potential hazard, there has been a long history of monitoring at Rabaul, and more recently, a major AUSAID project to understand the detailed seismic and crustal environment of the volcano. We have undertaken in collaboration with Dr. R. W. Johnson (AGSO-Geoscience Australia) and the Rabaul Volcano Observatory, a detailed petrologic and geochemical study of the products of the latest eruption, and a more extended study of the history of the volcano for the past few thousand years. Given that Rabaul is now one of the best understood active volcanoes in terms of current seismicity, our hope is that significant integration of the petrologic evolution with crustal structures and magma chamber configuration can be achieved.

Links

Recent Publications

Spandler, C., K. Worden, R. Arculus, et al., Igneous rocks of the Brook Street Terrane, New Zealand: implications for Permian tectonics of eastern Gondwana and magma genesis in modern intra-oceanic volcanic arcs. New Zealand Journal of Geology & Geophysics, 2005. 48 (1): p. 167-183.

Spandler, C., J. Mavrogenes, and R. Arculus, Origin of chromitites in layered intrusions: Evidence from chromite-hosted melt inclusions from the Stillwater Complex. Geology, 2005. 33 (11): p. 893-896.

Okamura, S., R.J. Arculus, and Y.A. Martynov, Cenozoic magmatism of the north-eastern Eurasian margin: The role of lithosphere versus asthenosphere. Journal of Petrology, 2005. 46 (2): p. 221-253.

McConachy, T.F., R.J. Arculus, C.J. Yeats, et al., New hydrothermal activity and alkalic volcanism in the backarc Coriolis Troughs, Vanuatu. Geology, 2005. 33 (1): p. 61-64.

Baker, E.T., G.J. Massoth, K. Nakamura, et al., Hydrothermal activity on near-arc sections of back-arc ridges: Results from the Mariana Trough and Lau Basin - art. no. Q09001. Geochemistry Geophysics Geosystems, 2005. 6 : p. 9001.

Sun, W.D., R.J. Arculus, V.S. Kamenetsky, et al., Release of gold-bearing fluids in convergent margin magmas prompted by magnetite crystallization. Nature, 2004. 431 (7011): p. 975-978.

Spandler, C., J. Hermann, R. Arculus, et al., Geochemical heterogeneity and element mobility in deeply subducted oceanic crust; insights from high-pressure mafic rocks from New Caledonia [Review]. Chemical Geology, 2004. 206 (1-2): p. 21-42.

Spandler, C., J. Hermann, R. Arculus, et al., Reply to comments on ''Redistribution of trace elements during prograde metamorphism from lawsonite blueschist to eclogite facies: implications for deep subduction zone processes''. Contributions to Mineralogy & Petrology, 2004. 148 (4): p. 506-509.

Zhang, L., D.J. Ellis, R.J. Arculus, et al., 'Forbidden zone' subduction of sediments to 150 km depth - the reaction of dolomite to magnesite plus aragonite in the UHPM metapelites from western Tianshan, China. Journal of Metamorphic Geology, 2003. 21 (6): p. 523-529.

Sun, W.D., V.C. Bennett, S.M. Eggins, et al., Enhanced mantle-to-crust rhenium transfer in undegassed arc magmas. Nature, 2003. 422 (6929): p. 294-297.

Sun, W.D., R.J. Arculus, V.C. Bennett, et al., Evidence for rhenium enrichment in the mantle wedge from submarine arc-like volcanic glasses (Papua New Guinea). Geology 31(10 Suppl, 2003. 31 (10 Suppl 1): p. 845-848.

Sun, W., V.C. Bennett, S.M. Eggins, et al., Rhenium systematics in submarine MORB and back-arc basin glasses: laser ablation ICP-MS results. Chemical Geology, 2003. 196 (1-4): p. 259-281.

Spandler, C.J., R.J. Arculus, S.M. Eggins, et al., Petrogenesis of the Greenhills Complex, Southland, New Zealand: magmatic differentiation and cumulate formation at the roots of a Permian island-arc volcano. Contributions to Mineralogy & Petrology, 2003. 144 (6): p. 703-721.

Spandler, C., J. Hermann, R. Arculus, et al., Redistribution of trace elements during prograde metamorphism from lawsonite blueschist to eclogite facies; implications for deep subduction-zone processes. Contributions to Mineralogy & Petrology, 2003. 146 (2): p. 205-222.

Parkinson, I.J., R.J. Arculus, and S.M. Eggins, Peridotite xenoliths from Grenada, Lesser Antilles Island Arc. Contributions to Mineralogy & Petrology, 2003. 146 (2): p. 241-262.

Bryant, C.J., R.J. Arculus, and S.M. Eggins, The geochemical evolution of the Izu-Bonin arc system: A perspective from tephras recovered by deep-sea drilling - art. no. 1094 [Review]. Geochemistry Geophysics Geosystems, 2003. 4 : p. 1094.

Arculus, R.J., Use and abuse of the terms calcalkaline and calcalkalic. Journal of Petrology, 2003. 44 (5): p. 929-935.

Kamenetsky, V.S., A.V. Sobolev, S.M. Eggins, et al., Olivine-enriched melt inclusions in chromites from low-Ca boninites, Cape Vogel, Papua New Guinea: evidence for ultramafic primary magma, refractory mantle source and enriched components. Chemical Geology, 2002. 183 (1-4): p. 287-303.

Frost, B.R., C.G. Barnes, W.J. Collins, et al., A geochemical classification for granitic rocks [Review]. Journal of Petrology, 2001. 42 (11): p. 2033-2048.

Spandler, C.J., S.M. Eggins, R.J. Arculus, et al., Using melt inclusions to determine parent-magma compositions of layered intrusions: Application to the Greenhills Complex (New Zealand), a platinum group minerals-bearing, island-arc intrusion. Geology, 2000. 28 (11): p. 991-994.

Parkinson, I.J. and R.J. Arculus, The redox state of subduction zones: insights from arc-peridotites. Chemical Geology, 1999. 160 (4): p. 409-423.

Bryant, C.J., R.J. Arculus, and S.M. Eggins, Laser ablation-inductively coupled plasma-mass spectrometry and tephras: A new approach to understanding arc-magma genesis. Geology, 1999. 27 (12): p. 1119-1122.

Arculus, R.J., H. Lapierre, and E. Jaillard, Geochemical window into subduction and accretion processes: Raspas metamorphic complex, Ecuador. Geology, 1999. 27 (6): p. 547-550.

Okamura, S., R.J. Arculus, Y.A. Martynov, et al., Multiple Magma Sources Involved in Marginal-Sea Formation - Pb, Sr, and Nd Isotopic Evidence from the Japan Sea Region. Geology, 1998. 26 (7): p. 619-622.

Cosca, M.A., R.J. Arculus, J.A. Pearce, et al., Ar-40/Ar-39 and K-Ar Geochronological Age Constraints for the Inception and Early Evolution of the Izu-Bonin-Mariana Arc System. Island Arc, 1998. 7 (3): p. 579-595.

Gust, D.A., R.J. Arculus, and A.B. Kersting, Aspects of Magma Sources and Processes in the Honshu Arc. Canadian Mineralogist 35(Part, 1997. 35 (Part 2): p. 347-365.

Bryant, C.J., R.J. Arculus, and B.W. Chappell, Clarence River Supersuite - 250 Ma Cordilleran Tonalitic I-Type Intrusions in Eastern Australia. Journal of Petrology, 1997. 38 (8): p. 975-1001.

Thirlwall, M.F., A.M. Graham, R.J. Arculus, et al., Resolution of the Effects of Crustal Assimilation, Sediment Subduction, and Fluid Transport in Island Arc Magmas - Pb-Sr-Nd-O Isotope Geochemistry of Grenada, Lesser Antilles. Geochimica et Cosmochimica Acta, 1996. 60 (23): p. 4785-4810.

Kersting, A.B., R.J. Arculus, and D.A. Gust, Lithospheric Contributions to Arc Magmatism - Isotope Variations Along Strike in Volcanoes of Honshu, Japan. Science, 1996. 272 (5267): p. 1464-1468.

Kersting, A.B. and R.J. Arculus, Pb Isotope Composition of Klyuchevskoy Volcano, Kamchatka and North Pacific Sediments - Implications for Magma Genesis and Crustal Recycling in the Kamchatkan Arc. Earth & Planetary Science Letters, 1995. 136 (3-4): p. 133-148.

Chen, W. and R.J. Arculus, Geochemical and Isotopic Characteristics of Lower Crustal Xenoliths, San Francisco Volcanic Field, Arizona, USA. Lithos, 1995. 36 (3-4): p. 203-225.

Arculus, R.J. and D.A. Gust, Regional Petrology of the San Francisco Volcanic Field, Arizona, USA. Journal of Petrology, 1995. 36 (3): p. 827-861.

Thirlwall, M.F., T.E. Smith, A.M. Graham, et al., High Field Strength Element Anomalies in Arc Lavas - Source or Process. Journal of Petrology, 1994. 35 (3): p. 819-838.

Smith, D., R.J. Arculus, J.E. Manchester, et al., Garnet-Pyroxene-Amphibole Xenoliths from Chino Valley, Arizona, and Implications for Continental Lithosphere Below the Moho. Journal of Geophysical Research-Solid Earth, 1994. 99 (B1): p. 683-696.

Loferski, P.J., R.J. Arculus, and G.K. Czamanske, Rare Earth Element Evidence for the Petrogenesis of the Banded Series of the Stillwater Complex, Montana, and Its Anorthosites. Journal of Petrology, 1994. 35 (6): p. 1623-1649.

Kersting, A.B. and R.J. Arculus, Klyuchevskoy Volcano, Kamchatka, Russia - the Role of High-Flux Recharged, Tapped, and Fractionated Magma Chamber(S) in the Genesis of High-Al2o3 from High-Mgo Basalt. Journal of Petrology, 1994. 35 (1): p. 1-41.

Arculus, R.J., S. Banno, J. Charvet, et al., Tectonics, Metamorphism and Magmatism in Islands Arcs - Preface. Lithos, 1994. 33 (1-3): p. 1-2.

Arculus, R.J., ASPECTS OF MAGMA GENESIS IN ARCS [Review]. Lithos, 1994. 33 (1-3): p. 189-208.

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