Joshua Davies

J.Davies
Université du Québec à Montréal
Département des sciences de la Terre et de l'atmosphère

davies.joshua [at] uqam.ca

I am a geochemist that specializes in the use of U-Pb geochronology to understand how the earth and its biosphere have evolved over time. I am particularly interested in developing new methods for generating highly precise and accurate ages and then applying these age constraints to a range of geological problems. I have recently been interested in understanding the causes of mass extinctions and determining the link between these biotic crisis and the eruption and emplacement of large igneous provinces. This link can only be determined through understanding the precise and absolute chronology of the events in geological time. Associated with this problem is the inherent difficulty in dating mafic igneous rocks which are the most important component of large igneous provinces.
I’m also interested in developing precise chronologies of events in the stratigraphic record to help understand the evolution of the near surface environment. The events I’m interested in range from cyclic sedimentary variations in Paleoproterozoic rocks which we can use to understand the climate on earth billions of years ago, to understanding changes that lead to the development of snowball earth. The approaches we take to understand these events inevitably involves radiochronologic techniques, but more and more frequently we are combining these with cyclostratigraphy and Bayesian modelling to improve our understanding of the geological record.

My research is both lab based and field based. In the lab, my group uses ultra clean environments and the EARTHTIME spikes to separate U and Pb from minute minerals and measure their isotopic compositions at high precision and generate precise and accurate ages. We also use lasers and ICP-MS mass spectrometers to quickly collect age and isotope (usually U-Pb + Hf) data from a range of minerals. We are also particularly keen on developing new analytical techniques. The field work we conduct is often in remote locations on all corners of the planet, and the samples we collect and questions we investigate allow a large range of collaborations with numerous international groups.

Percival, L.M.E., Davies, J.H.F.L., Schaltegger, U., De Vleeschouwer, D., Da Silva, A.-C., Föllmi, K.B., 2018. Precisely dating the Frasnian-Famennian boundary: Implications for the cause of the Late Devonian mass extinction. Scientific Reports 8(1), art. no. 9578. 

Davies, J.H.F.L., Sheldrake, T.E., Reimink, J.R., Wotzlaw, J.-F., Moeck, C., Finlay, A., 2018. Investigating Complex Isochron Data Using Mixture Models. Geochemistry, Geophysics, Geosystems 19(10), 4035-4047. 

Farina, F., Dini, A., Ovtcharova, M., Davies, J.H.F.L., Greber, N.D., Bouvier, A.-S., Baumgartner, L., Ulianov, A., Schaltegger, U., 2018. Zircon petrochronology reveals the timescale and mechanism of anatectic magma formation. Earth and Planetary Science Letters 495, 213-223. 

Schaltegger, U., Davies, J.H.F.L., 2018. Petrochronology of zircon and baddeleyite in igneous rocks: Reconstructing magmatic processes at high temporal resolution. Petrochronology: Methods and Applications, 297-328. 

Davies, J.H.F.L., Stern, R.A., Heaman, L.M., Moser, D.E., Walton, E.L., Vennemann, T., 2018. Evaluating baddeleyite oxygen isotope analysis by secondary ion mass spectrometry (SIMS). Chemical Geology 479, 113-122. 

Callegaro, S., Marzoli, A., Bertrand, H., Blichert-Toft, J., Reisberg, L., Cavazzini, G., Jourdan, F., Davies, J.H.F.L., Parisio, L., Bouchet, R., Paul, A., Schaltegger, U., Chiaradia, M., 2017. Geochemical constraints provided by the Freetown Layered Complex (Sierra Leone) on the origin of high-ti tholeiitic CAMP magmas. Journal of Petrology 58(9), 1811-1840.

Davies, J.H.F.L., Marzoli, A., Bertrand, H., Youbi, N., Ernesto, M., Schaltegger, U., 2017. End-Triassic mass extinction started by intrusive CAMP activity. Nature Communications 8, art. no. 15596. 

Marzoli, A., Davies, J.H.F.L., Youbi, N., Merle, R., Dal Corso, J., Dunkley, D.J., Fioretti, A.M., Bellieni, G., Medina, F., Wotzlaw, J.-F., McHone, G., Font, E., Bensalah, M.K., 2017. Proterozoic to Mesozoic evolution of North-West Africa and Peri-Gondwana microplates: Detrital zircon ages from Morocco and Canada. Lithos 278-281, 229-239. 

Reimink, J.R., Davies, J.H.F.L., Chacko, T., Stern, R.A., Heaman, L.M., Sarkar, C., Schaltegger, U., Creaser, R.A., Pearson, D.G., 2016. No evidence for Hadean continental crust within Earth's oldest evolved rock unit. Nature Geoscience 9(10), 777-780. 

D'Abzac, F.-X., Davies, J.H.F.L., Wotzlaw, J.-F., Schaltegger, U., 2016. Hf isotope analysis of small zircon and baddeleyite grains by conventional Multi Collector-Inductively Coupled Plasma-Mass Spectrometry. Chemical Geology 433, 12-23. 

Reimink, J.R., Davies, J.H.F.L., Waldron, J.W.F., Rojas, X., 2016. Dealing with discordance: A novel approach for analysing U–Pb detrital zircon datasets. Journal of the Geological Society 173(4), 577-585. 

Davies, J.H.F.L., Stern, R.A., Heaman, L.M., Rojas, X., Walton, E.L., 2015. Resolving oxygen isotopic disturbance in zircon: A case study from the low δ18O Scourie dikes, NW Scotland. American Mineralogist 100(8-9), 1952-1966. 

Davies, J.H.F.L., Heaman, L.M., 2014. New U-Pb baddeleyite and zircon ages for the Scourie dyke swarm: A long-lived large igneous province with implications for the Paleoproterozoic evolution of NW Scotland. Precambrian Research 249, 180-198. 

Davies, J.H.F.L., Wotzlaw, J.-F., Wolfe, A.P., Heaman, L.M., 2014. Assessing the age of the Late Cretaceous Danek Bonebed with U–Pb geochronology. Canadian Journal of Earth Sciences 51(11), 982-986. 

Hughes, H.S.R., McDonald, I., Goodenough, K.M., Ciborowski, T.J.R., Kerr, A.C., Davies, J.H.F.L., Selby, D., 2014. Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths. Precambrian Research 250, 97-126. 
 

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Codirection : A. Marzoli, U. Padua
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dos Santos Jr., Angelo : Doctorat en sciences de la Terre et des planètes
Department of Earth and Planetary Sciences, McGill
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Dufour, Frédéric : Doctorat en sciences de la Terre et de l'atmosphère
Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal
Codirection : Ross Stevenson; Galen Halverson
Sujet de recherche : Timing and paleopoles of the mafic rocks from the Bylot basins, in Baffin Island and Northwest Greenland
Gitzhoffer, Alexandre : Maîtrise en sciences de la Terre
Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal
Codirection : S. De Souza, UQAM
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Department of Earth and Planetary Sciences, McGill
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Pinon, Héloïse : Doctorat en sciences de la Terre et de l'atmosphère
Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal
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Sujet de recherche : Géochronologie des bentonites de la plate-forme St-Laurent dans la région de Montréal : corrélations stratigraphiques et implications géotechniques et tectoniques.
Sanchez, Vanessa : Maîtrise en sciences de la Terre
Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal
Codirection : Alain Tremblay
Sujet de recherche : Stratigraphie et caractérisation pétrographique et géochimique des K-bentonites de la région de Montréal.
Segner, Martin : Doctorat en sciences de la Terre
Codirection : U. Schaltegger, U. Geneva
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Warren, Shannon : Maîtrise en sciences de la Terre
Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal
Codirection : Galen Halverson
Sujet de recherche : Improving chronology of the Pre-Sturtian isotope excursions using Bayesian modelling and improved maximum depositional ages.