Grace Anne Stewart Speaker Series

Celebrating Diversity in the Earth & Atmospheric Sciences Department

November 22, 2019: Industry and Government Panel Discussion and Networking Session

Featuring Guest Speakers:

  • Astrid Arts, Cenovus Energy
  • Karen Fallas, Geological Society of Canada
  • Dr. Gabrielle Gascon, Environment and Climate Change Canada
  • Sheri Gilmour, Stantec Consulting Ltd.
  • Dr. Carolyn Relf, Yukon Geological Survey

12:00 - 1:00 pm; Tory 3-36
ATLAS talk with Dr. Carolyn Relf: Evaluating Yukon's Geothermal Potential

5:00 - 6:30 pm; Tory 3-36
Industry and Gov't Panel: Diversity and Professional Development in the
Geosciences (PD hour for Grad. Students))

6:30 - 8:30 pm; Faculty Club
Networking Session, Wine & Cheese

About the Speaker Series

The Grace Anne Stewart Speaker Series connects students and faculty of the Earth and Atmospheric Science (EAS) department to a greater diversity of female scientists by inviting two female scientists to visit the department each year. The program is designed to expand the professional networks of faculty and students, foster discussion about gender equity, and provide students with more female role models/mentors.

Grace Anne Stewart Speakers are invited to participate in several events during a 1-2 day visit:

  • A one-hour research talk presented as part of the ATLAS talk series. These talks are coordinated by the EAS department's graduate student society and are attended by department students (graduate and some undergraduate), post-doctoral researchers, and faculty members.
  • A 'Behind the Scenes' informal question and answer session where graduate students can learn more about the speaker's career path.
  • A wine and cheese social event with department faculty and graduate students.
  • Additional small group or one-on-one meetings with faculty or students with shared interests. These might include lab tours or class visits.

Past Speakers

  • 2016 - Dr. Patricia F. Allwardt

    The Role of Structural Geology in Exploration Risk Assessment

    Nov 18th 2016: Dr. Patricia F. Allwardt

    Talk abstract:

    Understanding regional and local scale structure is crucial to the assessment of petroleum system risk elements during the subsurface characterization of exploration opportunities. At the play scale, crustal architecture and regional rift geometries impact the deposition of source rock, reservoir, and seal intervals; and crustal heat flows and overburden thickness impact source rock maturation and reservoir quality. Local structural evolution impacts trap configuration, reservoir presence and thickness, seal preservation and integrity, charge timing, and fetch and migration considerations. This presentation provides an overview of the impact of structural evolution on each of the petroleum system risk elements, drawing on examples from various global offshore basins. It then reviews a case study from the heavily salt modified deep water Gulf of Mexico basin.

    In the Gulf of Mexico, the deposition of 40,000 to 50,000 ft of Upper Mesozoic and Cenozoic sediments above a thick (up to 15,000 ft) Callovian autochthonous salt layer, which overlies basement of varying architecture, has led to the development of a complex sedimentary basin that is punctuated by mobile salt and its remnants. Our interpretation of the salt framework reveals that salt tectonic style varies systematically across the northern Gulf of Mexico and can be spatially characterized. Within this framework, we differentiate and define domains of distinct salt tectonic style in which trap geometries and formation mechanisms are similar, and leads share common critical risks. This type of analysis provides input for where to focus exploration work program efforts.


    Tricia Allwardt is a structural geologist with ConocoPhillips in Houston, TX. She received a B.A. in earth and planetary sciences from Harvard University and a Ph.D. in structural geology and geomechanics from Stanford University. Since joining ConocoPhillips in 2006, she has spent 4 years working on worldwide reservoir structure and geomechanics projects in Technology, and 6 years in Exploration contributing to the Gulf of Mexico, Nova Scotia, and Newfoundland exploration programs. Tricia is currently transitioning to a position in ConocoPhillips' Eagle Ford Development organization. She is an AAPG, EAGE, and HGS member and has served as an Associate Editor for the AAPG Bulletin since 2010.

  • 2016 - Dr. Susan Kidwell

    Dr. Susan Kidwell - William Rainey Harper Professor of Geosciences, University of Chicago

    Sponsored by John-Paul Zonneveld and Atlas

    Dead shells do tell tales: Evaluating human impacts using the youngest fossil record

    Biologists and the public increasingly appreciate the many ways that humans interact with natural systems, mostly to the detriment of wild species and habitats. However, data are difficult to acquire for more than a few select species and for the past several decades to centuries that are needed to recognize change, discriminate between natural and human drivers, and establish natural baseline conditions. Field work, experiments, and modeling are revealing that death assemblages - the actively accumulating shells and bones encountered in present-day seabeds and landscapes - are remarkably reliable sources of historical ecological information at precisely these scales despite the perils of skeletal destruction and 'time-averaging'. Paleontologists are now testing this approach in a large range of settings to develop it as a standard method for the toolkit of conservation biologists and environmental managers. Such studies turn uniformitarianism upside-down - we are applying earth science methods to very young fossil records to better understand modern-day biota. The effort to get a mechanistic understanding of death assemblage preservation is, however, also yielding insights relevant to deep-time records and to the long-term burial and recycling of biogenic carbonates.

  • 2017 - Dr. Ellyn Enderlin

    Understanding Variability in Glacier Behavior in a Changing Climate

    March 31, 2017: Dr. Ellyn Enderlin

    Talk abstract:

    Over the last two decades, atmospheric and oceanic warming have driven increases in surface meltwater runoff and iceberg discharge from the Greenland Ice Sheet. Although spatial and temporal variations in surface meltwater runoff can largely be explained by changes in air temperature, the link between iceberg discharge variability and climate change is relatively poorly understood.
    The over-arching goal of my research is to develop an improved understanding of the relative influence of changing air and ocean temperatures as well as the internal controls of glaciers, such as geometry, on iceberg discharge. Using remotely-sensed ice thickness and velocity observations, I've shown that spatial and temporal variations in iceberg discharge have resulted in large variability in the contribution of individual glaciers to sea level rise since 2000. My ongoing research projects use a combination of in situ and remotely sensed data to investigate potential explanations for the observed variability. In this presentation I will focus on one aspect of my ongoing research projects: ice-ocean interactions. Specifically, I will show how repeat stereo satellite images can be used to quantify spatial and temporal variations in glacier submarine melting. I will also show how a variety of remotely sensed datasets can be combined to assess the influence of changing ice-ocean interactions on iceberg discharge and the freshwater fluxes from the mélange of icebergs, bergy bits, and sea ice in Greenland's glacial fjords. The results of these ongoing analyses support the need for the continued development of novel observational techniques and interdisciplinary research efforts to improve predictions of glacier change and the associated impacts on the Earth system.


    Ellyn Enderlin is a Research Assistant Professor at the University of Maine. She completed her Ph.D. research under the supervision of Dr. Ian Howat (Glacier Dynamics Group, Byrd Polar and Climate Research Center) in 2013. Since then, she has been working at the University of Maine Climate Change Institute. Ellyn's research projects focus on combining remotely-sensed and in situ observations and numerical ice flow modeling to develop a better understanding of the environmental triggering mechanisms and internal controls of marine-terminating glacier behavior (i.e., glacier dynamics). Ellyn is particularly interested in glacier-ocean interactions, namely submarine melting and iceberg calving, and how changes in these interactions influence the rate of mass loss from the fast-flowing glaciers that drain the Greenland and Antarctic ice sheets. Ellyn is co-chair of the US national committee for the Association of Polar Early Career Scientists (USAPECS). For more information about Ellyn Enderlin, visit her website:

  • 2017 - Dr. Rebecca Flowers

    Cratonic surface histories, kimberlites, and mantle dynamics

    Dr. Rebecca Flowers - University of Colorado

    The Grace Anne Stewart Speaker Series is excited to announce Dr. Rebecca Flowers as our distinguished speaker for the fall of 2017. Dr. Flowers will be visiting the department Oct. 26-27, with her keynote address at noon on Friday the 27th.

    Research Interests: Dr. Flowers focuses on understanding how deep Earth and surface processes are coupled over hundreds of millions of years. She employs field observations, geochronology, and thermochronology to address a wide variety of research problems. In particular, she has recently employed (U-Th)/He geochronology to the study of kimberlite emplacement ages, the age of formation of the Grand Canyon, and the reconstruction of large impact basins.

    Biography: Dr. Flowers is an Assistant Professor at the University of Colorado, Boulder. She completed her Ph.D. at MIT and a postdoc at Caltech, before serving as a Humboldt Research Fellow at the University of Tubingen, Germany. She has received various awards, including the prestigious NSF CAREER award for junior faculty, and has served on both the EarthScope and Mineralogical Society of America Distinguished Lecturer programs.

  • 2018 - Dr. Anat Shahar

    Exploring Planetary Differentiation through an Isotopic Lens

    Dr. Anat Shahar, Carnegie Institution of Washington

    February 9, 2018

    The Grace Anne Stewart Speakers Series is excited to announce that Dr. Anat Shahar from the Carnegie Institute will be visiting our Department February 9. She will be delivering a keynote address at noon, but we invite all members of the department to chat with her over lunch or to sign up for a private meeting.


    Planetary differentiation occurred at high temperature, high pressure, varying oxygen fugacity and on bodies with varying compositions. The specific conditions at which bodies differentiated can be probed and the chemical fingerprints of that differentiation can be found in stable isotope ratios measured today in natural samples. Experiments are key to understanding the mechansims behind the fractionations seen in nature as the pressure, temperature and compositional space can be interrogated systematically. In this talk I will focus on how pressure, temperature and composition affect the partitioning of isotopes between metal and silicate. In particular I will focus on whether experiments can explain the isotopic signatures found in rocks on Earth and if the light element in the core has left a fingerprint on the isotopic ratios in the mantle.


    Dr. Shahar received her PhD at UCLA and is currently a Staff Scientist at the Geophysical Laboratory at the Carnegie Institution of Washington. She is a Fellow of the Mineralogical Society of America and has received numerous awards including excellence in teaching awards and the prestigious Clarke Medalist from the Geochemical Society.

  • 2018 - Dr. Carrie Tyler

    Ecological Networks: The Impacts of Invasion on Paleocommunity Dynamics

    Dr. Carrie Tyler

    March 16, 2018

    The Grace Anne Stewart Speakers Series is excited to announce that Dr. Carrie Tyler from Miami University (Oxford, Ohio) will be visiting our Department March 16. She will be delivering a keynote address at noon, but we invite all members of the department to chat with her over lunch or to sign up for a private meeting. Please email the for more information.


    The fossil record documents dramatic ecosystem changes that can be used to understand how and why past ecosystems have changed. But can we use paleocommunities as an analog for modern communities? In this talk, after assessing the reliability of the fossil record, we will examine the effects of invasion on marine paleocommunities by comparing modeled food web structure, stability, and resilience during the Late Ordovician. We find that the growing consensus is that skeletal remains and fossil assemblages can be used to evaluate changes in ecosystems today. Thus, our findings have important consequences for conservation and management efforts, as they suggest that (1) invasion led to destabilization and loss of resilience, and (2) that functional richness may play a more critical role in long-term ecosystem stability and persistence than biodiversity.


    Dr. Tyler is an Assistant Professor at Miami University in Oxford, Ohio. She received her Ph.D. in Geosciences at the Virginia Tech and completed a post-doctoral fellowship at the Florida Museum of Natural History, University of Florida. She currently holds two NSF grants investigating the biotic interactions of echinoids, and modelling community complexity and stability through periods of biotic escalation and community disturbance.

    Research Interests:

    Dr. Tyler is a palaeobiologist, conducting research which investigates processes governing the distribution, palaeoecology, and evolution of marine invertebrates, the role of taphonomy and the fidelity of the fossil record in the development of macro-evolutionary and macro-ecological models, the application and development of quantitative palaeontological methods, morphometrics and functional morphology of marine invertebrates, and ecosystems response to and recovery from perturbation.

  • 2018 - Dr. Lesley Warren

    Mining waste environments: globally significant and growing biogeochemical hotspots ,

    Dr. Lesley Warren, Lassonde Institute of Mining, University of Toronto

    November 23, 2018

    Talk abstract: Globally, extractive industries are estimated to produce 7.2 billion tons of waste and use 7-9 billion m of water; creating one of the fastest growing and least well studied biogeochemical contexts on the planet. Tailings, containing reactive sulfur, iron, nitrogen and carbon compounds, represent the largest global mining environmental liability. Currently, it is difficult for mines to design tailings impoundments or develop effective management and reclamation approaches, because the microbial processes that generate impacts remain a black box. However, as mining landscapes continue to grow world-wide, the fundamental lessons learned in these contexts are also required to better inform our understanding of global biogeochemical cycling. Here, I will present results from both metal and oil sands mining contexts, where we have begun to address this knowledge gap through the joint application of genomics and geochemistry. Research to date provides fascinating glimpses of extensive and often surprising biogeochemical cycling within these environments, as well as distinctive microbial communities that interactively shape biogeochemical outcomes.

    Research interests Dr. Warren holds the Claudette MacKay-Lassonde Chair in Mineral Engineering and is the director of the Lassonde Institute of Mining. She is an applied geochemist and molecular microbiologist. Her main focus is applying emerging molecular biological techniques to mining contexts to explore the roles of bacteria in affecting water quality. This research information produced develops new tools to enhance environmentally sound practices in the mining industry.

  • 2018 - Drs. Chris Schneider and Georgia Hoffman

    71 (combined) years as a woman in the field: Perspectives as student, academic, industry, and government geoscientists

    Dr. Chris Schneider and Dr. Georgia Hoffman

    Tuesday April 3rd, 2018, 5PM, ESB 1-23

    Professional Development Seminar:
    71 (combined) years as a woman in the field: Perspectives as student, academic, industry, and government geoscientists
    The Grace Anne Stewart Speaker Series will be holding a discussion-based question-and-answer session about what it is like to be a woman and a professional geoscientist. The guest speakers will be Georgia Hoffman and Chris Schneider and the seminar will be held in ESB 1-23 at 5 pm on Tuesday, April 3rd. This session will count as Professional Development hours for graduate students who attend. Please email the for more information.

    Chris Schneider received B.A. degrees in geology and archaeology from the University of Minnesota in 1999 and a Ph.D. in geology from the University of Texas at Austin in 2003. After that, she spent 5 years in postodoctoral positions and visiting assistant professorships at Cornell College, Appalachian State University, California State University at Bakersfield, University of California, Davis, and Colorado College. On moving to Canada, she worked three years at the Alberta Geological Survey as a carbonate stratigrapher, leaving that job to return to teaching by becoming sessional for one semester at the University of Alberta. Chris is currently a geological specialist for Beryl Mining Company, currently under contract to Suncor, and is an adjunct professor in Earth and Atmospheric Sciences. Chris's research includes geohazards and carbonate stratigraphy beneath the oil sands, mass extinction survivorship with relevance to creating successful marine protected areas, and climate change effects on marine intertidal ecosystems.

    Georgia Hoffman received a B.A. in geology from the University of Pennsylvania in 1970. She then moved to Alberta and began an M.Sc. in geology at the University of Alberta, but when a summer job mapping coal deposits in the foothills turned into a permanent job, she began a career in industry. She has worked for a variety of mining companies, energy companies, and consulting companies, and in 1995 she completed an M.Sc. in Biological Sciences (Paleobotany) at the U of A. Most recently, she has worked for Beryl Mining Company under contract to Suncor, and for Aeon Paleontological Consulting Ltd.

  • 2019 - Dr. Hanika Rizo

    Winter 2019 Talk: Tungsten-182 anomalies in terrestrial rocks: Evidence for core-mantle chemical interaction?

    Dr. Hanika Rizo, Carleton University

    Friday, March 15th, 2019 - Explore the world of extinct isotopes in terrestrial rocks

    Core-mantle chemical interaction is a topic that has been hotly debated for decades. While physical (e.g. thermal) interactions across the core-mantle boundary suggest chemical exchange is also expected, it is generally assumed that the Earth's core has been chemically isolated since its formation. This is because unequivocal geochemical evidence for this exchange has been difficult to find. The short-lived 182Hf-182W isotope system (t1/2=8.9 Ma) has always been considered to have potential to provide evidence for this process. This is because the W concentration and 182W isotopic composition of the core and the mantle can be assumed significantly different. Since W is siderophile and Hf is lithophile, core-mantle differentiation led to significant differences in the W concentration of these reservoirs. Since this differentiation occurred during the lifetime of the Hf-W system, the extinct isotope 182Hf decayed into 182W entirely in the mantle, leaving the core with an unradiogenic 182W isotopic composition. Thus, any core material "leaking" into the mantle could be detected in the 182W isotopic composition of magmas associated with deep mantle plumes. In this seminar, I will present and discuss 182W data for Hadean and Archean mantle-derived rocks that together with 182W data recently obtained in ocean island basalts, might provide the most compelling evidence to date that mantle plumes carry a core geochemical signature.

    Research Interests: Hanika's research interests are primarily focused on early earth geochemical processes. Hanika uses extinct isotopic systems, 182Hf-182W and 146Sm-142Nd, to understanding the timing and extent of metal segregation into earths core, the crystallization of earths magma ocean, and the effect of meteoritic bombardment on the silcate earth between 4.5 and 3.9 Ga.

  • 2019 - Dr. Myriam Telus

    Fall 2019 Talk: The Carbonaceous Chondrite Record of Icy Planetesimals

    Dr. Myriam Telus, University of California, Santa Cruz

    Friday, October 18, 2019
    Atlas Talk: Noon, Tory 3-36
    Meet the Speaker: 1PM, Tory 3-36


    Carbonaceous chondrites show evidence for significant water-rock alteration that is thought to have occurred within ice-rich planetesimals. In this presentation, I will review our current understanding of the formation and evolution of icy planetesimals. In particular, I focus on my recent work on understanding the composition and formation conditions of Ca-carbonates in CM chondrites (Telus et al., 2019, GCA). These minerals formed via direct precipitation from the fluid and/or water-rock interactions in the parent asteroid. To understand the formation conditions of carbonates in CM chondrites, the C and O isotopic composition of Ca-carbonates and the O isotopic composition of magnetite were measured. I also discuss whether our data support current carbonaceous chondrite parent body models and how this work relates to current asteroid exploration missions.