Introduction: Georgian Bay bedrock erosion: evidence for regional floods
This video introduces a series of 6 videos joined to our publication in the Geological Survey of Canada Open file report and survey in the area of French River, Ontario. The 6 videos illustrate 7 sites among the 16 surveyed sites between 2017 and 2019.
Plucking Island - Part 5 of 6
The 5th of this series of 6 is joined to our publication in the in the Geological Survey of Canada Open file report and survey in the area of French River, Ontario. The 6 videos illustrate 7 sites among the 16 surveyed sites between 2017 and 2019. "Georgian Bay bedrock erosion: evidence for regional floods" 2022.2.
Cavitation Island - Part 6 of 6
The 6th of this series of 6 is joined to our publication in the in the Geological Survey of Canada Open file report and survey in the area of French River, Ontario. The 6 videos illustrate 7 sites among the 16 surveyed sites between 2017 and 2019. "Georgian Bay bedrock erosion: evidence for regional floods" 2022.
Germain Island - Part 3 of 6
The 3rd of this series of 6 is joined to our publication in the in the Geological Survey of Canada Open file report and survey in the area of French River, Ontario. The 6 videos illustrate 7 sites among the 16 surveyed sites between 2017 and 2019. "Georgian Bay bedrock erosion: evidence for regional floods" 2022.
Outer Fox Island - Part 2 of 6
The 2nd of this series of 6 is joined to our publication in the in the Geological Survey of Canada Open file report and survey in the area of French River, Ontario. The 6 videos illustrate 7 sites among the 16 surveyed sites between 2017 and 2019. "Georgian Bay bedrock erosion: evidence for regional floods" 2022.
The process of s-forms during megaflood
Towards the end of the ice age melt water from glaciers played a major role in shaping our land. During the last decades, glaciologists were able to recognize the traces of these subglacial water floods. This video will help to appreciate how vortex are carving the sculpted forms (s-forms) on the bedrock under the continental ice sheet.
Cantley, Québec - Monument de l'Ère Glaciaire
Cette vidéo a été présentée à la conférence CANQUA / AMQUA 2018 à Ottawa afin de préparer les téléspectateurs à une visite sur le site exceptionnel de Cantley, au Québec. La visite sur le terrain a été dirigée par David R. Sharpe de la Commission géologique du Canada. Vers la fin de l'époque glacière l'eau de fonte des glaciers a joué un rôle plus important que l'on ne croyait. Ces eaux auraient été la cause de plusieurs catastrophes à l'échelle régionale sur plusieurs continents. Le site de Cantley au Québec est un des sites le plus emblématique de l’une de ces catastrophes. Les roches sculptées sont d’âge précambrienne du Grenville. Ce marbre contient un grand nombre de morceaux granitiques que nous appelons inclusions. Ces inclusions résistèrent mieux que le marbre aux eaux catastrophiques ce qui engendra une multitude de s-forms appelées ‘obstacle marks’, marques d’obstacle. En regardant les animations qui se superposent aux affleurements, le spectateur saisira facilement, par intuition, l’action des puissants vortex. L’évènement s’est sans doute produit dans une brève lapse de temps que les islandais appellent un Jökulhlaup.
Cantley, Quebec - Monument of the Ice Age
This video was presented at the CANQUA/AMQUA 2018 conference in Ottawa to prepare viewers for a field trip to the amazing site of Cantley, Quebec. The field trip was led by David R. Sharpe of the Geological Survey of Canada. The site was sculpted by catastrophic subglacial water at the end of the last Ice Age. The main s-forms are obstacle marks caused by the presence of harder granitic inclusion inside the white marble.
In memory of John Shaw (1943- 2018)
Glacial sediments and landforms do not give up their secrets readily. Over many years, John Shaw did much to uncover these secrets with his curiosity, passion, analytical ability, knowledge of fundamental physical processes, and a few radical ideas. With a thorough grounding in sedimentary and erosional processes, and meticulous and insightful field observation, he offered provocative and insightful analyses of many aspects of glacial sediments and landforms that are widely influential. Born in Glasgow and having grown up in Leeds, he began his academic career with BSc (geography, geology and mathematics) and PhD degrees at the University of Reading. In 1969, he moved to Canada taking a faculty position in physical geography in the Department of Geography, University of Alberta (Edmonton) where he embarked on his research and was an enlightening and dedicated teacher. His development of ideas on subglacial meltwater processes began while at Alberta and advanced further during his professorship at Queen’s University, Kingston, Ontario (1982-1990). John continued his work on subglacial meltwater processes after he returned to the University of Alberta (1990-2011) as Chair of Geography, then as a member of the Department of Earth and Atmospheric Sciences. He collaborated on research on subglacial meltwater systems and esker deposits. With Bruce Rains, a supportive colleague and close friend for many years, and their students, he did both detailed and synoptic work on glacial landforms of Alberta, culminating in a series of papers and a well-known map and interpretation based on digital elevation data and field interpretation of sediments. At this time, he also produced the Canada-wide map of large, regional-scale flow tracts of subglacial bedforms based on up-dated remote sensing data. John’s ideas were, and remain, controversial. He raised fundamental questions about understanding of glacial processes and glacial landscape evolution. These ideas undeniably have stimulated the research field. Despite intense skepticism from some, John and his students investigated glacial landscapes and their landforms—hummocky terrain, tunnel channels and eskers, relating them to the meltwater hypothesis. John excelled at teaching. Students were engaged by his enthusiasm and his clarity of explanations and by his willingness to encourage students to have confidence to think for themselves and make their own discoveries. He introduced many undergraduate and graduate students to his brand of careful field observation grounded in physical theory and analysis, while occasionally intimidating and enlightening them with physics and fluid dynamics at a time when this was rare in glacial geomorphology. He was a supportive mentor and supervisor, giving students the freedom to take their own direction. Later in his career he was also a proud ‘academic grandfather’. He was often at his best in a gravel pit nudging students to make observations and inferences based on the sediments they saw, while helping them see where the limit to interpretation was: “Were you there?” he might ask if you went too far. Later in his career, John was denied the pleasure and fulfillment of teaching, and students missed out on the benefits of his knowledge and insights, due to institutional heavy handedness.
Hydraulic Shock by Subglacial Water - French River
At the end of the ice age, the subglacial floods were so powerful that new unsuspected phenomena are reveal by field works. Above s-forms and cavitation, we can observe in French River exfoliation joints generated by hydraulic shock or commonly named water hammer.
Revisiting Siccar Point - A New Perspective
Siccar Point is the most famous outcrop in the history of modern geology. For centuries geologists visit the site influenced by the same old ideas not noticing some of the very odd elements of this unconformity. It seems as if the old Silurian strata/slabs were thrusting upward like pistons disturbing non stop the Upper Devonian sedimentation. That might explain another oddity: The Silurian basement bears no trace of chemical alteration by weathering. Yes there is a differential eroded surface of the Silurian but not a one as seen today. The basal conglomerate of the Upper Devonian reminds the violent erosion of our modern "wadi" (flooding river in desert) and for that reason the desert/wadi interpretation is commonly accepted today. If the Silurian bedrock was tectonically thrusting up during the fast Devonian sedimentation one might draw two conclusions: 1- The violent upheaval of the topography should be the main cause for the flooding/debris flow not the one triggered by weather fluctuation. 2- This sort of syn-tectonic sedimentation make this phenomenon an event uncommon today.