Much of the research undertaken by EOS solid earth scientists is encompassed by the themes: (i) the assembly and deformation of continental lithosphere, and (ii) the origins and evolution of magmas and fluids within the crust and upper mantle. These themes are investigated through a range of petrological, geochemical and geophysical research programs that exploit theory, laboratory experiments and field studies conducted over a broad range of spatial and temporal scales. Most recently, we have expanded our expertise and our research focus to begin to ask fundamental questions concerning the physical and chemical evolution of condensed planetary bodies.
Departmental work on continental evolution is focused on Canada's youngest and oldest geological provinces. The assembly of the Cordilleran orogen is investigated using geochronological dating, structural geology and deep seismic profiling to establish the origin, timing and rates of assembly, deformation and internal structure of Cordilleran terranes. Geophysical and petrological studies of the Cascadia subduction zone are directed toward understanding dynamic processes within the slab and mantle wedge that contribute to earthquakes and crustal growth. At the other extreme in time, EOS research is unveiling the mysteries of Earth's oldest cratonic nuclei, in particular, the Slave province in Canadas Northwest Territories. Seismological studies have focused on mapping the depth and stratigraphy of the thick continental roots to the Slave craton. The rheological, petrological, and thermal properties of the underlying mantle lithosphere have been probed by studies of xenoliths and diamond inclusions transported to the surface via abyssal kimberlites. The cumulative impact of these investigations has been to provide new fundamental insights into the constitution and origins of the thick continental mantle lithosphere underlying the Slave craton.
The nature of fluid (in the broadest sense) transport within the solid Earth pervades many EOS research programs. Within the upper crust, major contributions have been made to the understanding of reactive, aqueous fluid flow in high temperature environments, enabling improved interpretation of chemical (e.g., isotopic) and mineral alteration patterns. The models developed for high-temperature reactive transport of crustal fluids have been used to understand and predict distributions of metamorphic rocks (regional and contact), the origins and evolution of fluids during contact metamorphism, and the feedback relationships between temperature, mineral reactions, porosity-permeability and fluid flow. Experimental rock deformation studies are providing key insights into the time-scales and mechanisms of deformation operating at pressure-temperature-fluid conditions found within the crust. Results from these experimental studies provide hard quantitative data upon which rheological models for processes governing mountain building events are built.
Within the crustal and mantle dynamics theme, there is great interest in the origins of magmatism and the physical-chemical processes governing the evolution and eruption of magma (volcanism). Our faculty are at the cutting edge of deciphering the origin and transport of magmas that feed volcanic systems, layered intrusions, and large igneous provinces. Isotopic studies focus on determining the time scales and mantle source reservoirs of major magmatic events for both ancient (Muskox, Stillwater) and modern plume (Hawaii, Kerguelen) systems. We also develop computational models that simulate the thermodynamic and geochemical consequences of magmatic processes (e.g., of differentiation, mixing and assimilation); these models are used to unravel the formation conditions and mantle sources to igneous rocks. Ongoing field-based, isotopic, and volcanological studies of Cenozoic volcanoes across the Canadian Cordillera are providing a regional framework for understanding the post-amalgamation distribution of magmatism within the Cordillera and across the terrane framework. Parallel studies of mantle xenoliths hosted by young lavas have provided a vehicle for directly studying the nature (homogeneous vs. heterogeneous) and origins (allochthonous vs. autochthonous) of the mantle lithosphere underlying the Canadian Cordillera and its relationship to Cenozoic magmatism. Our research efforts also encompass petrological, isotopic and volcanological studies of kimberlite bodies and have been aimed at: constraining the nature and origins of kimberlite magmas, fingerprinting diamondiferous vs. barren kimberlite bodies, and developing physical models for the eruption of kimberlite.
Most recently, the Crustal and Mantle Dynamics theme has encompassed planetary-scale scientific issues. At the planetary scale, experimental and theoretical fluid dynamics are being applied to examine how mantle convection leads to volcanism, not only on Earth but also on Mars and Venus. We anticipate that this newest initiative will grow substantially over the next few years and ultimately lead to collaborative investigations utilizing the geophysical, geochemical and petrological talents within our department.
(* - more than 25; ** - more than 50; *** more than 100 citations.)
|*||Bostock MG (1997) Anisotropic upper-mantle stratigraphy and architecture of the Slave craton. Nature, 390 (6658), 392-395.|
|**||Bostock MG (1998) Mantle stratigraphy and evolution of the Slave province. Journal of Geophysical Research-Solid Earth, 103 (B9), 21183-21200.|
|**||Bostock MG, Hyndman RD, Rondenay S, and Peacock SM (2002) An inverted continental Moho and serpentinization of the forearc mantle. Nature, 417 (6888), 536-538.|
|**||Harrison TM and Clarke GKC (1979) Model of the thermal effects of igneous intrusion and uplift as applied to Quottoon pluton, British Columbia. Canadian Journal of Earth Sciences, 16(3), 411-420.|
|***||Clowes RM, Brandon MT, Green AG, and Yorath CJ (1987) A Sutherland Brown, ER Kanasewich, and C Spencer. LITHOPROBE-Southern Vancouver Island: Cenozoic subduction complex imaged by deep seismic reflections. Canadian Journal of Earth Science, 24, 31-51.|
|**||Clowes RM and 7 others (1992) LITHOPROBE -- New perspectives on crustal evolution. Canadian Journal of Earth Science, 29, 1813-1864.|
|**||Clowes RM, Zelt CA, Amor JR, and Ellis RM (1995) Lithospheric structure in the southern Canadian Cordillera from a network of seismic refraction lines. Canadian Journal of Earth Science, 32, 1485-1513.|
|***||Ferry JM and Dipple GM (1991) Fluid flow, mineral reactions, and metasomatism. Geology, 19, 211-214.|
|**||Dipple GM and Ferry JM (1992) Metasomatism and fluid flow in ductile fault zones. Contributions to Mineralogy and Petrology, 112, 149-164.|
|*||Reilinger R, Ergintav S, Bürgmann R, McClusky S, Lenk O, Barka A, Gurkan O, Hearn E, Feigl KL, Cakmak R, Aktug B, Ozener H, and Toksoz MN (2000) Coseismic and Postseismic Fault Slip for the 17 August 1999, M = 7.5, Izmit, Turkey Earthquake. Science, 289, 1519-1524.|
|**||Kopylova MG, Russell JK, and Cookenboo H (1999) Petrology of peridotite and pyroxenite xenoliths from the Jericho kimberlite: Implications for the thermal state of the mantle beneath the Slave craton, Northern Canada. Journal of Petrology, 40, 79-104.|
|**||Mortensen JK (1992) Pre-Mid-Mesozoic tectonic evolution of the Yukon-Tanana Terrane, Yukon and Alaska. Tectonics, 11, 836-853.|
|**||Mortensen JK (1993) U-Pb geochronology of the eastern Abitibi Subprovince. 1. Chibougamau-Matagami-Joutel region. Canadian Journal of Earth Sciences, 30, 11-28.|
|**||Mortensen JK (1993) U-Pb geochronology of the eastern Abitibi Subprovince. 2. Noranda-Kirkland Lake region. Canadian Journal of Earth Sciences, 30, 29-41.|
|**||Russell JK and Nicholls J (1988) Analysis of Petrologic Hypotheses with Pearce Element Ratios. Contributions in Mineralogy Petrology, 99, 25-35.|
|*||Stanley CR and Russell JK (1989) Petrologic Hypothesis testing with Pearce Element Ratio Diagrams: Derivation of Diagram Axes. Contributions in Mineralogy Petrology, 103, 78-89.|
|*||Pearce TH, Russell JK, and Wolfson, I (1987) Laser Interference and Nomarski Interference Imaging of Zoning Profiles in Plagioclase Phenocrysts from the May 18th, 1980 Eruption of Mt. St. Helens, Washington. American Mineralogist, 72, 1131-1143.|
|*||Mitchell JN, Scoates JS, and Frost CD (1995) High-Al gabbros in the Laramie anorthosite complex, Wyoming: implications for the composition of melts parental to Proterozoic anorthositesy. 119, 166-180.|
|**||Gautier I, Weis D, Mennessier J-P, Vidal P, Giret A, and Loubet M (1989) Petrology and geochemistry of Kerguelen basalts: evolution of an hotspot from a ridge to an intraplate position. Earth and Planetary Science Letters, 100, 59-76.|
|**||Weis D, Frey FA, Leyrit H, and Gautier I (1993) Kerguelen Archipelago revisited: Geochemical and isotopic study of the SE Province lavas. Earth and Planetary Science Letters, 118, 101-119.|
|*||Weis D, Frey FA, Giret A, and Cantagrel JM (1998) Geochemical characteristics of the youngest volcano (Mount Ross) in the Kerguelen Archipelago: inferences for magma flux and composition of the Kerguelen Plume. Journal of Petrology, 39, 973-994.|