Talk
Colloquium: Dr. Ryan Venturelli - Holocene retreat and re-advance: untangling past [in]stabilities of the West Antarctic Ice Sheet
When
· 12:20 PM MDT
Shown in the venue’s time zone (America/Denver), not yours.
Where
Boulder, CO
Tickets
No on-sale date recorded
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What the source said
Dr. Ryan Venturelli Colo School of Mines Topic: Holocene retreat and re-advance: untangling past [in]stabilities of the West Antarctic Ice Sheet Academic Host: Bob Anderson Abstract: Reconstructions of past ice sheet behavior enable us to refine physical models that predict how much, how fast, and from where ice mass loss will contribute to future sea level rise. In Antarctica, geological constraints on paleo ice thickness obtained from above the modern ice surface (e.g., exposure age data from deglaciated nunataks) and on paleo ice extent obtained outboard from modern margins (e.g., sediment core and geomorphic data from the ice-free continental shelf) have served as the primary tools to reconstruct ice sheet change from the Last Glacial Maximum to present. Recent efforts to recover sediment and bedrock from beneath grounded ice in Antarctica offer complimentary insight into deglaciation and help constrain the inland extent of grounding line retreat. Adding subglacial sampling to our paleoglaciological perspective has begun to erode a decades-long paradigm of monotonic deglaciation in favor of the idea that the Antarctic Ice Sheet was less extensive in the Holocene than it is today. In this talk, I will present two complementary lines of evidence for retreat and re-advance dynamics in Antarctica. First, recent subglacial drilling efforts provide direct constraints on the southernmost extent of grounding line retreat in West Antarctica. Second, because subglacial drilling cannot be scaled continent wide, I share how three decades of legacy cosmogenic nuclide data may lend insight into thinning-thickening cycles consistent with widespread grounding line retreat and re-advance. These new constraints on the timing and extent of grounding line retreat prior to the modern observational record allow for a mechanistic understanding of the drivers of marine ice-sheet growth. By generating this process-to-paleo perspective, we can create the context required to reduce uncertainty in sea-level projections on societally relevant timescales.