Video Presents Shaw’s Flood Hypothesis for Some North American Drumlins

▶

Key facts

• The video argues, citing John Shaw’s 1989 hypothesis, that pressurized subglacial meltwater floods formed some drumlin fields; drumlin origins in general remain debated.
• John Shaw, a University of Alberta geomorphologist, introduced the flood hypothesis in his 1989 paper Drumlins and catastrophic subglacial floods.
• Jerome Lessemann, then Shaw’s graduate student at the University of Alberta, documented drumlin swarms in British Columbia.
• A drumlin’s blunt end generally faces upstream and its tapered end downstream, so its long-axis orientation can indicate paleoflow direction.
• Large drumlin fields provide many flow-direction measurements, but their orientations alone do not prove that all the drumlins formed simultaneously.
• The Livingstone Lake flood’s estimated peak discharge was about 84,000 m³/s—a flow rate—not a total volume of 84,000 km³.
• The video interprets British Columbia drumlin orientations as evidence of flow from the north; this does not establish one flood across North America or exclude a separate glacial Lake Missoula flood.

← All stories

AI-generated text · images from the original sources · always verify with the sources.