Department of Geology

Seminars & Events

The Department of Geology regularly hosts internal and external speakers during the academic year. Most talks are open to the public. For the most up-to-date information on upcoming events, please consult the list below or follow us on Twitter.


 

2018-2019 Seminar Series


 Dipicolinic acid as a tracer for oil seeps in marine sediments

 

Dr. Jayne Rattray, Energy Bioengineering and Geomicrobiology Group,

University of Calgary

 

Monday, September 17 @ 11:30AM

Science 411

 

Understanding the sediment biogeography of dormant marine thermophilic bacterial endospores (thermospores) has the potential to assist locating and characterising working petroleum systems. The presence of thermospores in cold ocean environments suggests that distribution occurs via hydrocarbon seepage from thermally active reservoirs. Low abundance and endospore coat physiology mean nucleic acid based techniques have limited success for in situ detection of  hermospores. The biomarker 2,6-pyridine dicarboxylic acid (dipicolinic acid or DPA) is specific to endospore-forming bacteria from the phylum Firmicutes, and constitutes a significant percentage of endospore dry weight. DPA is therefore a potential biomarker for sediment dwelling thermospores and hydrocarbon rich thermal seeps however its suitability for seabed screening surveys has so far not been tested. DPA distribution was assessed in surface sediment samples at 97 locations in the Eastern Gulf of Mexico and results from both oil positive and oil negative sites were compared. Recent expeditions in Canadian waters to the Scotian shelf and Laurentian channel have provided both oil positive and negative sediment cores, and enabled higher resolution down-core DPA depth profiles. In this seminar we showcase our findings investigating the efficacy of DPA as a biomarker for tracing thermospores and oil seeps in marine sediments.

 


 

Hypervelocity impact effects on Earth: Causes, consequences and future threats

 

Dr. John Spray, Planetary and Space Science Centre, 

University of New Brunswick, Fredericton

 

Thursday, October 18 @ 1:00PM

Science 411

 


Hypervelocity impact effects in our Solar System are now widely appreciated as having contributed to fundamental planet-building and planet-modifying processes throughout geological time. The strain rates at which impact events take place are exceptional relative to the timescales of most geological processes with which we are familiar. Hypervelocity impact can cause intense shock loading resulting in melting, vaporization and even plasma formation in target rocks. Further from the contact and the compression locus (>50 GPa), shock waves cause local melting and solid-state phase transformations with the creation of new structural states and mineral polymorphs. An overview will be presented with emphasis on terrestrial impact cratering. Approximately 200 impact structures are now proven on Earth, which is a shadow of its true historical record. This paucity of craters is due to Earth being an active planet and it having erased the majority of past impact evidence due to plate tectonics, volcanic activity, burial and erosion. Nevertheless, valuable examples have survived: we will tour some of them and explore the intriguing products of hypervelocity impact as we strive to understand these extreme processes. We will also consider the future and what threats are posed to our social infrastructure by asteroids and comets colliding with Earth.

 


 

2018-2019 GAC Howard Street Robinson Lecture Series

The Precambrian Secrets of Yukon

Howard Street Robinson Medalist

 

Dr. Derek Thorkelson, Department of Earth Sciences,

Simon Fraser University

 

Thursday, November 8 @ 1:00PM

Science 411

 

Announcement

 

Most geologists in Canada regard the Canadian Cordillera as a Phanerozoic orogen consisting of fold belts and accreted terranes rich in precious and base metal deposits, and flanked by the modern Cascadia subduction zone. To the surprise of many, the orogen also preserves a rich Precambrian history that spans over a quarter of Earth history. The most extensive Precambrian exposures are preserved in structural culminations in Yukon Territory. Few academic researchers have worked in these vast and mysterious mountains, and it has taken decades to unlock their geological secrets. Although each step was important, our most revealing strides have come in the past few years. We have developed a new, deeper understanding of how northwestern Canada evolved during the Proterozoic and participated in the construction and break-up of the supercontinents Nuna and Rodinia. This talk will provide a backdrop of information followed by recent research highlights including our new model of Proterozoic terrane accretion, and a glance toward future research. 

 


 

Science Atlantic-AGS Speaker Tour

Forensic petrology applied to the Titanic headstones

 

Dr. Barrie Clarke, Department of Earth Sciences, 

Dalhousie University

 

Tuesday, November 20 @ 1:00PM

Science 411

 

Announcement

 

All but one of the 150 victims of the Titanic disaster buried in Halifax, Nova Scotia, have petrologically identical gabbro (“black granite”) headstones. After being in place for nearly a century, one headstone had become damaged, so the City of Halifax sought to replace it; however, there was no historical or archival record of where these headstones had come from, and thus the solution as to their place of origin had to be determined scientifically. Just as DNA is unique to each living thing, so every rock also has a unique set of characteristics (age, minerals, texture, and chemical composition) that sets it apart from every other rock. Ideally, the headstones should match only the quarry where they were extracted. But there are tens of thousands of quarries in the world, so which was the right one? This presentation describes how, using the best sleuthing techniques of Sherlock Holmes and CSI combined with multivariate statistics, we located the source quarry in southwestern New Brunswick.

 


 

Active Marine Geohazards on the seafloor of Eastern and Arctic Canada

 

Dr. Alexandre Normandeau, Research Scientist, Marine Geoscience

Geological Survey of Canada, Bedford Institute of Oceanography

 

Thursday, November 22 @ 1:00PM

Science 411

 

 Announcement

 

Submarine landslides and turbidity currents are gravity flows that transfer large amounts of sediment and organic carbon to the deep-sea. They represent major geohazards as they can sever fiber-optic communication cables, rupture subsea pipelines, and damage oil and gas infrastructures. Thus, an understanding of where, when and how they occur is critical to mitigating their impact. Because there are so few direct observations of turbidity currents and submarine landslides, the factors responsible for triggering them are poorly known and understood. This presentation will illustrate the controls governing the most recent and active geohazards observed on the seafloor of both eastern and Arctic Canada. In eastern Baffin Island fjords, the behaviour of retreating glaciers dictates the presence or absence of turbidity currents on delta fronts. In southeastern Canada, glaciers are now absent, suggesting that most geohazards occurred during the late-Pleistocene when glaciers provided large volumes of sediment to the continental slope. However, new mapping of the southeastern Canadian shelf and margin has revealed recent giant landslides and active turbidity currents. Offshore of Nova Scotia, a submarine landslide deposit the size of Lake Ontario, triggered between 4 and 1.5 ka BP, was just discovered. Additionally, a monitoring program undertaken in the Gulf of St. Lawrence combining repeat mapping of the seafloor with acoustic doppler current profilers (ADCPs) revealed the recurring presence of turbidity currents that lead to the migration of bedforms on the seafloor. Geohazards in eastern and Arctic Canada, therefore, appear to be more active than previously thought; we need only look in the right locations with a fresh perspective!