Professor Hilary Downes
Professor of Geochemistry
Department of Earth Sciences and Planetary Science
Birkbeck College
University of London
Malet St
London WC1E 7HX
Tel 020 7679 7712
Fax 020 7679 2867
e-mail: h.downes@ucl.ac.uk
Teaching
- Igneous and Metamorphic Petrology 2nd year
- Chemical Evolution of the Earth 3rd/4th year
- Magmatic Processes/ Volcanism in the Solar System 3rd/4th year
- Selected lectures for MRes
Professional associations
- Fellow of the Geological Society
- Chartered Geologist
- Member of the American Geophysical Union
- Member of the Mineralogical Society
- Member of IAVCEI
- Member of Meteoritical Society
Research interests
My research concerns the origin and evolution of the Earth’s continental lower crust and the lithospheric upper mantle. The lithospheric mantle can act either as a source of magma or as a "sink" for magma rising from the deeper convecting asthenospheric mantle. I have studied suites of mantle xenoliths from France, Hungary, Romania, Italy, Montana (USA) and Serbia. I have shown that interaction between asthenospheric magmas and the lithospheric mantle can have many different forms, ranging from the formation of widespread veins in the mantle to more pervasive metasomatism. Neogene magmatism of western and central Europe consists largely of alkali basalts derived from the asthenosphere, but which have interacted to some extent with the lithosphere.
The continental lower crust is a poorly understood region of the Earth, which can be best investigated by the study of xenoliths brought to the surface by volcanic eruptions. I have investigated in detail the composition, mineralogy and geochemistry of granulite xenoliths from the lower crust of both ancient cratonic continental crust in the Baltic Shield (Russia) and young thin crust in regions such as the Pannonian Basin (Hungary). I have used a variety of modern geochemical and isotopic techniques, including ion-probe and laser-fluorination for oxygen isotopes. Some regions of the lower crust are formed by direct underplating of magma but others (such as in Hungary) appear to be accreted portions of oceanic crust.
I am also interested in the geodynamics of magma-genesis, and I have investigated intra-plate and subduction-related magmatism in France, Italy, Hungary, Romania, Ukraine and Serbia. I recently started a series of projects in the Cape Verdes Islands in collaboration with Dr Simon Day. I have research students studying carbonatite magmatism in Kola and the Cape Verdes, and mantle xenoliths from Cape Verdes and the western USA. Other students are working on cumulate xenoliths and pyroclastic volcanism from the Cape Verdes, and the Gardar alkaline province in Greenland. Click here to see some pictures of the Cape Verdes!
I have published more than 70 research papers on a diverse range of topics and have edited volumes of papers on magmatism and xenoliths in Europe. All of this research helps to enhance my teaching, particularly of advanced modules in petrology and geochemistry. I am now extending my research to the mantle of other planets. I recently spent a sabbatical in Houston, Texas, working at the Lunar and Planetary Institute and collaborating with colleagues at the Johnson Space Centre and the University of Wisconsin. We studied a suite of meteorites called “ureilites” which are fragments of the mantle of an unknown asteroid. I am planning to continue this work with colleagues from UCL, the Natural History Museum (London) and we have a new PhD student starting to work on ureilites.
Publications
Beard, A.D., Downes, H., Hegner, E. and Sablukov, S. 2000. Geochemistry and mineralogy of kimberlites from the Arkhangelsk region, NW Russia. Lithos, 51, 47-73.
Claesson, S., Vetrin, V., Bayanova, T. and Downes, H. 2000. U-Pb zircon ages from a Devonian carbonatite dyke, Kola peninsula, Russia: A record of geological evolution from the Archaean to the Palaeozoic. Lithos, 51, 95-108.
Markwick, A.J.W. and Downes, H. 2000. Lower crustal granulite xenoliths from the Arkhangelsk kimberlite pipes: petrological, geochemical and geophysical constraints. Lithos, 51, 135-151.
Kempton P D, Downes H, Neymark L A, Wartho J A, Zartman R E and Sharkov E V, 2001. Garnet granulite xenoliths from the northern Baltic Shield - The underplated lower crust of a Palaeoproterozoic Large Igneous Province? Journal of Petrology. 42, 731-763.
Downes H, 2001. Formation and modification of the shallow sub-continental lithospheric mantle: evidence from ultramafic xenoliths suites and massifs of western and central Europe. Journal of Petrology. 42, 233-250.
Downes H, Thirlwall M F and Trayhorn S, 2001. Miocene subduction-related magmatism in southern Sardinia: Sr-Nd and oxygen isotopic evidence for mantle source enrichment. J Volcan. Geotherm. Res. 106, 1-21.
Seghedi I, Downes H, Pecskay Z, Thirlwall M F, Szakacs A, Prychodko M and Mattey D, 2001. Magmagenesis in a subduction-related post-collisional volcanic arc segment: the Ukrainian Carpathians. Lithos 57, 237- 262
Markwick A J W, Downes H and Veretennikov N, 2001. The lower crust of S.E. Belarus: Petrological, geochemical and geophysical constraints from xenoliths. Tectonophysics 339, 215-237
Downes H, Upton B G J, Handyside E and M F Thirlwall 2001. Geochemistry of mafic and ultramafic xenoliths from Fidra (Southern Uplands, Scotland): implications for lithospheric processes in Permo-Carboniferous times. Lithos 58, 105-124
Harangi Sz., Downes, H., Kósa, L., Szabó, Cs., Thirlwall, M.F., Mason, P.R.D. & Mattey, D. 2001: Almandine garnet in calc-alkaline volcanic rocks of the Northern Pannonian Basin (Eastern-Central Europe): geochemistry, petrogenesis and geodynamic implications. Journal of Petrology, 42, 1813-1843.
Downes H, Markwick A J W, Kempton P D and Thirlwall M F, 2002. The lower crust beneath cratonic north-east Europe – isotopic constraints from garnet granulite xenoliths. Terra Nova 13:395-400
Downes H, Peltonen P, Mantarii and Sharkov E V, 2002. Proterozoic zircon ages from lower crustal granulite xenoliths, Kola Peninsula, Russia: evidence for crustal growth and reworking. J Geol Soc 159, 485-488.
Downes H, Kostoula T, Jones A P, and Thirlwall M F 2002. Geochemistry and Sr-Nd isotope composition of peridotite xenoliths from Monte Vulture, south central Italy. Contributions to Mineralogy and Petrology 144, 78-92.
Marchev, P, Downes, H.. Thirlwall, M. F and Moritz R. 2002. Small-scale variations of 87Sr/86Sr isotope composition of barite in the Madjarovo low-sulphidation epithermal system, SE Bulgaria: implications for sources of Sr, fluid fluxes and pathways of the ore-forming fluids. Mineralium Deposita. 37, 669-677
Embey-Isztin A, Kempton P D, Downes H, Dobosi G 2003. Lower crustal granulite xenoliths from Pannonian Basin, Hungary. Part I. Mineral chemistry, thermobarometry and petrology . Contrib. Mineral. Petrol. 144, 652-670
Dobosi, G, Kempton, P D, Downes H, Embey-Isztin A, Thirlwall M F and Greenwood P 2003. Lower crustal granulite xenoliths from Pannonian Basin, Hungary, Part 2: Sr-Nd-Pb-Hf and O isotope evidence for formation of the continental lower crust by tectonic emplacement of oceanic crust. Contrib. Mineral. Petrol. 144, 671-683
Dobosi G., Downes H., Embey-Isztin A. and Jenner G.A 2003. Origin of megacrysts and pyroxenite xenoliths from the Pliocene alkali basalts of the Pannonian Basin (Hungary). Neues Jahrbuch Miner. Abh. 178, 217-237
Downes H, Reichow M, Mason P R D, Beard A D and Thirlwall M F 2003. Mantle domains in the lithosphere beneath the French Massif Central: a trace element and isotopic test. Chem Geol 200, 71-87.
Brassinnes S, Demaiffe D, Balaganskaya E and Downes H 2003. New mineralogical and geochemical data on the Vuorijarvi ultramafic, alkaline and carbonatitic complex (Kola Region, NW Russia). Per, Mineral. 72 (Special Issue Eurocarb), 79-86.
Seghedi I, Downes H, Szakacs A, Mason P R D, Thirlwall M F, Rosu E, Pecskay Z, Marton E & Panaiotu C. 2004. Neogene-Quaternary magmatism and geodynamics in the Carpathian-Pannonian region: a synthesis. Lithos, 72, 117-146.
Cvetkovic, V, Prelevic D, Downes H, Jovanovic M, Vaselli O and Pécskay Z, 2004. Origin and geodynamic significance of Tertiary post-collisional basaltic magmatism in Serbia (central Balkan peninsula). Lithos 73, 161-186.
Downes H, Beard A and Hinton R W 2004. Natural experimental charges: an ion-microprobe study of distribution coefficients in glass-rich hornblendite and clinopyroxenite xenoliths Lithos 75, 1-17.
H Downes, R Macdonald, B G.J. Upton, K G. Cox, J-L Bodiner, P R.D. Mason, D James, P. Hill and B C Hearn Jr 2004. Ultramafic xenoliths from the Bearpaw Mountains, Montana, USA: Evidence for multiple metasomatic events in the lithospheric mantle beneath the Wyoming craton. Journal of Petrology 45, 1631-1662.
Marchev P, Raicheva R, Downes H, Vaselli O, Chiaradia M and Moritz R, 2004. Compositional diversity of Eocene-Oligocene basaltic magmatism in the Eastern Rhodopes, SE Bulgaria: implications for genesis and tectonic setting. Tectonophysics. 393, 301-328
Seghedi I, Downes H, Vaselli O, Szakacs A, Balogh K and Pecskay Z, 2004. Post-collisional Tertiary-Quaternary mafic alkaline magmatism in the Carpathian-Pannonian region: a synthesis. Tectonophysics 393, 43-62
Dessai, A. G. Markwick, A. Vaselli O. and Downes H 2004. Granulite and pyroxenite xenoliths from the Deccan Trap: Insight into the nature and composition of the lower lithosphere beneath cratonic India. Lithos 78, 263-290.
Cvetkovic V, Downes H, Prelevic D Jovanovic M 2004. Characteristics of the lithospheric mantle beneath East Serbia inferred from ultramafic xenoliths in Paleogene basanites. Contrib. Mineral. Petrol. 148, 335-357.
Prelevic D, Foley S. F., Romer R. L., Cvetkovic V and Downes H 2005. Tertiary ultrapotassic volcanism in Serbia: constraints on petrogenesis and mantle source characteristics. J Petrology 46, 1443-1487
Papp D C, Ureche I, Seghedi I, Downes H and Dallai L 2005. Petrogenesis of convergent-margin calc-alkaline rocks and the significance of the low oxygen isotope ratios: the Rodna-Bargau Neogene subvolcanic area (Eastern Carpathians). Geolog. Carpat. 56, 77-90.
Seghedi, I, Downes H, Harangi Sz, Mason P R.D. and Pécskay Z. in press. Geochemical response of magmas to Neogene-Quaternary continental collision in the Carpathian-Pannonian region: a review. Tectonophysics.
Downes H, Balaganskaya E, Beard A Liferovich R, and Demaiffe D, 2005. Petrogenetic processes in the ultramafic, alkaline and carbonatitic magmatism in the Kola Alkaline Province: a review. Lithos 85, 48-75.
Wittig N, Baker J A and Downes H, 2006. Dating the mantle roots of young continental crust. Geology. 34, 237-240.
Harangi S, Downes H and Seghedi I (2006) Tertiary-Quaternary subduction provesses and related magmatism in Europe. European Lithosphere Dynamics GSL Memoir 32, 167-190.
Wilson M and Downes H (2006) Tertiary-Quaternary intra-plate magmatism in Europe and its relationship to mantle dynamics. European Lithosphere Dynamics. European Lithosphere Dynamics GSL Memoir 32, 147-166.
Wittig N, Baker J A, Downes H 2007. U-Th-Pb and Lu-Hf isotopic constraints on the evolution of sub-continental lithospheric mantle, French Massif Central. Geochimica et Cosmochimica Acta, 71, 1290-1311.
Beard A, Downes H, Mason P R D and Vetrin V R 2007. Depletion and enrichment processes in the mantle beneath the Kola peninsula: evidence from spinel peridotite xenoliths. Lithos 94, 1-24.
Cvetkovic V, Lazarov M, Downes H, Prelevic D 2007 Modification of the subcontinental mantle beneath East Serbia: evidence from orthopyroxene-rich xenoliths Lithos 94, 90-110.
Cvetkovic V, Downes H, Prelevic D, Lazarov M, Resimic-Saric C 2007. Geodynamic significance of ultramafic xenoliths from eastern Serbia: relics of sub-arc oceanic mantle? J. Geodynamics. 43, 504-527.
Downes H, Upton B G J, Connolly J, Beard A D, Bodinier J-L 2007. Petrology and geochemistry of a cumulate xenolith suite from Bute: evidence for late Palaeozoic crustal underplating beneath SW Scotland. J. Geol. Soc. 164, 1217-1231
Seghedi I, Bojar A-V, Downes H, Rosu E, Tonarini S, Mason P 2007. Generation of normal and adakite-like calc-alkaline magmas in a non-subductional environment: a Sr-O-H Isotopic study of the Apuseni Mountains Neogene magmatic province, Romania. Chemical Geology 245, 70-88.
Downes H. The origin of spinel- and garnet-pyroxenites in the shallow lithospheric mantle. Lithos in press
Harangi Sz, Downes H & Thirlwall MF in press. Geochemistry and petrogenesis of Miocene calc-alkaline volcanic rocks in the western Carpathian arc, Eastern Central Europe: evidence for an enriched mantle source J Petrology