(21Feb2024) On 18 March 2924 at 7:00pm the Puget Lobe Chapter io the IAFI will have Dr Ralph A Haugerud give his presentation “the Postmortem on the Southern Cordilleran Ice sheet. Death of an ice sheet can have many causes, as shown by retreat of the southern Cordilleran ice sheet about 15,000 years ago. East of the Cascades, the margin of active south-flowing ice retreated north as less snow fell and more melted. West of the Cascades, the Juan de Fuca lobe of the ice sheet appears to have floated away in response to rising sea level, perhaps without a proximal climatic cause. Collapse of the Juan de Fuca lobe diverted ice from the Puget lobe, which consequently stagnated at its margin and rapidly melted back. Later Sumas ice readvance in the Fraser Lowland may reflect stabilization of the remnant ice sheet by grounding as local sea level fell, followed by climate-driven retreat.
Ralph Haugerud received B.S. and M.S. degrees in Geology from Western Washington University and a Ph.D. in Geological Sciences from the University of Washington. Since joining the USGS in 1986, he has worked in the North Cascades Range, the Salish Lowland, and the Columbia Plateau. From 1990 to 2014 he was technical lead for the Puget Sound Lidar Consortium, and he has been instrumental in developing the GeMS standard for representing geologic maps in a Geographic Information System (GIS). His current efforts focus on the structure of Eocene strata in central Washington, features formed by glacial Lake Missoula outburst floods, and regional map compilation.
The in-person portion will be at Bellevue College Bldg R, Rm R103. See separate post for location details. For this meeting only there will be NO “Zoom” available.