This broad theme involves the investigation of sedimentological,
paleobiological, and climatological processes over geologic time. These
processes operate within the Earth’s surface and near-surface realms. A
variety of investigative techniques are employed, including field-based
studies, stable isotope analysis, petrography, subsurface data
analysis, major and trace element analysis, micro-imaging and numerical
analysis. These diverse techniques allow us to address a range of issues that
include: sea-level change, biodiversity change, climate change, mass
extinction, post-depositional processes, and
lithosphere-atmosphere-biosphere interactions throughout Earth’s
evolution. The range and scope of research projects within the Earth Evolution theme is
substantial, and there is major interaction and synergy between this and other research themes. However, Earth Evolution is distinguished by the
fact that investigations inevitably involve the issue of change through
time, whether over only a few hundred years to millions, or even
billions of years. Faculty members with interests in Earth Evolution include Patricia Corcoran,
Stephen R. Hicock, Jisuo Jin, Fred Longstaffe, Wayne Nesbitt, Guy
Plint, Cameron Tsujita and Elizabeth Webb. The interests of each
individual are briefly summarized below; further details of research
projects may be found on the research page of each faculty member. Factors that control the composition of sedimentary deposits;
tectonic setting, climate, provenance, transport, recycling,
depositional environment, and diagenesis. Collaborative projects involve
Precambrian sedimentary systems, Ordovician rocky shorelines, and
modern beach grain composition and textures. Analytical techniques
include trace element geochemistry, cathodoluminescence spectroscopy,
petrography, SEM, and FTIR. Glacial and Quaternary geology in parts of Canada and Antarctica. Ordovician-Silurian brachiopod taxonomy and diversity patterns
through time; origin, radiation, mass extinction, and recovery of
brachiopod faunas in the epicontinental seas of North America during the
Ordovician and Silurian periods; paleoecolgy and environmental control
on the evolution of brachiopod communities and faunas; comparative study
of Ordovician-Silurian brachiopod faunas of North America and other
regions – applications to global biodiversity patterns and
paleobiogeography. The use of O, H, C, and N isotopic ratios, including triple-isotope
ratios of oxygen, and mineralogy to understand lower temperature
lithosphere-biosphere-hydrosphere-atmosphere interactions. Large-scale
fluid-rock interaction, diagenesis and alteration in sedimentary basins
and other crustal rocks (Appalachian basin, Avalonia). Calibration and
application of isotopic proxies (e.g., precipitation, lakewater, DIC,
nitrate, cellulose, pollen, soil and sediment organic matter, shelly
fauna, and teeth, bones, tusks and hair [collagen, keratin, amino acids,
bioapatite phosphate and structural carbonate] of mammals – e.g.,
mammoths, mastodons, deer) for paleoecological and paleoclimatic
reconstruction. Paleolimnology and glacial meltwater movement in the
Great Lakes Basin over the last ~15,000 years (sediment cores:
porewater, ostracodes, organic matter, diatoms, and clay mineralogy). Redox reactions at MnO2 surfaces and production of toxins; Surface
properties of pentlandite and its flotation properties; Surface analysis
of As-bearing sulphide minerals using X-ray Photoelectron Spectroscopy
(XPS); Quantitative Secondary Ion Mass Spectrometry (SIMS) of minerals;
Inorganic and microbial alteration of arsenopyrite and pyrite or
marcasite; Weathering profile development. Clastic sedimentology and sequence stratigraphy of Cretaceous rocks
in the Western Canada foreland basin, using data from outcrop In the
Rocky Mountains coupled with a huge subsurface data base. Projects
broadly address high-resolution sequence stratigraphy, paleogeographic
evolution, causes, amplitude and timing of sea-level change, and
sedimentary-tectonic interactions. Projects with colleagues in North
America and Europe involve inter-regional correlation, molluscan
biostratigraphy, high-precision U-Pb geochronology, carbon-isotope
stratigraphy. Taphonomic (post-mortem) factors that control the preservation of
both hard and soft tissues of ancient organisms, including sedimentary
dynamics, bioturbation, geomicrobiological processes and later effects
of diagenesis. Paleoecology of invertebrate marine communities,
reconstruction of ancient marine environments, and event stratigraphy.
Collaborative projects include studies of the exceptionally preserved
Mazon Creek biota (Carboniferous), and paleoecological and taphonomic
aspects of Paleozoic mudrocks. Development of stable-isotope biogeochemistry techniques to
understand the interactions among the soil-plant-atmosphere continuum.
Paleoclimate models based on the isotopic analysis of ancient plant
materials (biogenic minerals and organic molecules) preserved in
terrestrial soils are used to assess climate change and the evolution of
biogeochemical cycles with implications for carbon sequestration, water
resource availability, weathering rates, drought and fire frequency and
ecosystem resilience in regions with high rates of natural or
anthropogenic vegetation change. Earth Evolution: Surface Life and Climate
Patricia Corcoran
Stephen R. Hicock
Jisuo Jin
Fred Longstaffe
Wayne Nesbitt
Guy Plint
Cameron Tsujita
Elizabeth Webb
Research Menu
Contacts
earth-sc@uwo.ca
519-661-3187
B&GS 1026
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