John Garver

John Garver in Alaska.

My year was dominated by a sabbatical, which allowed me to catch up on a number of ongoing research projects. Most of my time was spent writing, but I did manage to start in on some new work, which involves U/Pb dating of multiple domains in zircon. We started this at Arizona where we were double-dating zircons with different rim and core dates, and then we extended this work using laser depth profiling at Calgary.
This fascinating technique involves using a laser beam that is less than the width of a human hair to drill down into a zircon. As the laser gets deeper, the changes in isotopic ratios are directly related to the zircon growth ages of its “stratigraphy.” The goal here was to document the growth of Cretaceous (c. 88 Ma) rims on Precambri-an cores (1.3 to 1.7 Ga) from detrital zircon in Alaskan strata.
I am still working to understand the dynamic and hazards associated with ice jams. In January 2018, a warm spell resulted in a 17-mile-long ice jam on the Mo-hawk River. The event was prolonged because the jam was stuck in the Rexford Knolls (near GE R&D), and it was in place and partly blocking for about a month. We initiated several mapping programs using UAS (“drones”) to map the jam point, and determine ice thickness. I spent time working with State, county, and local emergency management official on the hazard and flooding potential related to this event.
In March 2018, Jackie Cockburn (University of Guelph) and I were again co-chairs for the Mohawk Watershed Symposium at Union (this was the 10th annual), which was well attended by both professionals and students. Union is still playing an important leadership role in the Mohawk Watershed. This year was a milestone be-cause it marked a decade of continuous annual meetings that have reshaped the dialog in the watershed. The Symposium has played a pivotal role in dovetailing science and policy in management decisions.
Research activity in tectonics was primarily focused on understanding the evolution of Cretaceous and Paleocene strata in Alaska and California. This summer we initiated a new phase of our research on the Cretaceous-Eocene strata in southern Alaska. Our field work was focused on northern Prince William Sound, and much of our daily activity was centered on Valdez. Our field area included two notable historic sites: Bligh reef where the Exxon-Valdez ran aground in 1989, and Unawick Bay near the epicenter of the 1964 Great Alaskan Earth-quake. This was a Keck Geology consortium project, and our field team of eight included collaborating students primarily from Union and Carleton colleges.

When the Keck Alaska group was at Prince William Sound this summer Spot Shrimp were caught while collecting rocks.

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