Geology Department Postgraduate Web Pages
Name: Michael Babechuk
Contact Details
Tel: +353 (0)1 896 2675
Fax: +353 (0)1 6711199
Email: mbabechuk@gmail.com
Title of Project
Behaviour of the transition metals during basaltic weathering: a temporal perspective
Project details
Weathering consumes substantial amounts of carbon dioxide from the atmosphere through water-rock reactions at the Earth’s surface. Over long geological time scales, these reactions are important for regulating the temperature of the Earth’s climate and are often cited as one of the key mechanisms responsible for triggering widespread glaciations throughout Earth history. Weathering profiles, which record the products of these water-rock reactions, are present throughout billions of years of the geological record. When combined with our understanding of how rocks weather at the modern Earth surface, ancient soils (paleosols) can be used to reconstruct certain paleoatmospheric parameters such as the amount of CO2 and O2 in the air.
My project is concerned with the weathering of one of the most common rock types on the planet, basalt, throughout different stages of the Earth’s history. Specifically, I am focusing on the change in the weathering behaviour of elements prior to and following the first accumulation of stable free oxygen in the atmosphere (roughly 2.3-2.4 billion years ago). To accomplish this, I am characterizing a recent weathering profile from the Deccan Traps in India and comparing it to two ancient paleosols. The first paleosol is located in Flin Flon, Manitoba (Canada) and formed ca. 1.9 billion years ago in an oxidative atmosphere. The second paleosol is located north of Thessalon, Ontario (Canada) and formed ca. 2.4 billion years ago in a reducing atmosphere. By studying these two ancient weathering profiles, new insights can be gained into the way rocks weathered under vastly different atmospheric conditions and how this influenced the transport of sediment and dissolved elements to the rivers and oceans.
To characterize each of these weathering profiles, I am combining traditional geochemical (major element) and mineralogical (XRD, petrography) techniques with newly developing high-precision ultra-trace element (Q-ICP-MS) and stable metal isotope techniques (TIMS, MC-ICP-MS). One of my primary aims is to provide a new framework under which the transition metal elemental and stable isotope record of paleosols may be linked with the information available from the hydrogenous and clastic sedimentary rock record. I am also in the process of developing and exploring the utility of new major element weathering indices to examine the chemistry of modern and ancient weathering profiles.
An earlier version of this project was conceived and initiated at Laurentian University (Sudbury, Ontario, Canada) where I was funded with a Natural Sciences and Engineering Research Council (NSERC) Alexander Graham Bell Canadian Graduate Scholarship. I am continuing and expanding the project at Trinity College Dublin with funding from an Ussher Fellowship.
Name of supervisor
Postgraduate personal details
I began my academic career at the University of Windsor (Ontario) with my B.Sc.H. in Geology. During the summers between coursework of my undergraduate degree, I worked in the Stable Isotope Laboratory (Department of Earth & Environmental Sciences) and the Geomicrobiology Laboratory (Great Lakes Institute for Environmental Science) with funding from NSERC undergraduate student research awards. My research assistance in the Geomicrobiology Lab focused on experimental modelling of microbially induced metal release from mine waste minerals under reducing conditions. This work led to two publications and catalysed my interest in the field of geochemistry. From Windsor, I moved to Sudbury to undertake my M.Sc. with Balz Kamber in the Chemical Fingerprinting Laboratory at Laurentian University (Ontario). For my M.Sc. research, I focused on the high field strength element composition of the depleted mantle and the fingerprint left behind from continental crust extraction over geological time. At Laurentian University, I gained substantial experience in high-precision ultra-trace element analysis, including clean room sample preparation (digestion, dilution), and gained an appreciation for the “art” of fingerprinting the signatures of processes occurring on the Earth today as well as those which occurred billions of years before the present. For my Ph.D. project, I continue to work with Balz Kamber in order to further develop my skills in analytical geochemistry and tackle some of the outstanding questions pertaining to the Precambrian Earth.
Project Start Date
September 01, 2010 – August 31, 2012 (Laurentian University), September 01, 2012 – August 31, 2015 (TCD)
Publications
Journal articles
Babechuk, M.G., Widdowson, M., Klinck, D., and Kamber, B.S. (In prep.) Quantifying chemical weathering intensity and associated elemental release from two contrasting basalt profiles, Deccan Traps, India.
Babechuk, M.G. and Kamber, B.S. (2011) An estimate of 1.9 Ga mantle depletion using the high-field-strength elements and Nd-Pb isotopes of ocean floor basalts, Flin Flon Belt, Canada. Precambrian Research. 189: 114-139.
Babechuk, M.G., Kamber, B.S., Greig, A., Canil, D. and Kodolányi, J. (2010) The behaviour of tungsten during mantle melting revisited with implications for planetary differentiation time scales. Geochimica et Cosmochimica Acta. 74: 1448-1470.
Babechuk, M.G., Weisener, C.G., Fryer, B.J., Paktunc, D. and Maunders, C. (2009) Microbial reduction of ferrous arsenate: biogeochemical implications for arsenic mobilization. Applied Geochemistry. 24: 2332-2341.
Weisener, C.G., Babechuk, M.G., Fryer, B.J. and Maunder, C. (2008) Microbial dissolution of silver jarosite: examining its trace metal behaviour in reduced environments. Geomicrobiology Journal. 25: 415-424.
Reports
Babechuk, M.G. and Kamber, B.S. (2010) Detailed (1:10 scale) mapping of regolith structure in dolerite below the Missi unconformity, Flin Flon area, Saskatchewan (part of NTS 63K12). Report of Activities 2010, Manitoba Innovation, Energy and Mines,
Manitoba Geological Survey: p. 94-104.
Fieldwork photos
Spheroidal weathering features (corestones) in dolerite regolith from the 1.9 Ga Flin Flon paleosol
Corestones and reworked regolith at the unconformity of the Flin Flon paleosol
Channel sampling approach to ensure continuous and representative analysis of the ancient paleosols. Channel is approximately 10 cm wide.