Bonneville lake basin shoreline records of large lake and abrupt climate change events

• Main Author: Nishizawa, Shizuo
• Format: Text
• Language: English
• Published: University of Utah 2012
• Subjects: Abrupt climate change events; Lake Bonneville; Lake surface area; Monsoons; Shoreline records; Greenland; Bonneville Lake; Basin Lake; Ice Sheet
• Online Access: https://dx.doi.org/10.26053/0h-2a5g-rp00; https://collections.lib.utah.edu/ark:/87278/s6tf0bvs

This study examines lacustrine shoreline sediment records of the Bonneville lake basin in North America. One of the most straightforward, robust, and useful characteristics of lacustrine shorelines is that shoreline features always form at water's edge to mark where the lake surface level is. Hence, mapping shoreline elevations enables researchers to reconstruct such physical dimensions of a paleolake as surface area, depth, and volume through geographic surveying, geomorphology, stratigraphy, sedimentology, tephrochronology, and radiocarbon dating. Good age control also makes it possible to put together lake size data from different time periods to chronicle details of when and how the lake changed its size in the past. Based on 200 radiocarbon dated shoreline data, this study presents a lake size change chronology of the Bonneville basin during the ice ages from 43,000 to 10,000 calendar years before present. Comparing the Bonneville basin lake record with the well resolved, high resolution ?18O records from the Greenland ice sheet, Venezuelan varved ocean sediments, and Chinese cave stalagmites reveals that timing, magnitude, and duration of all major lake change events in the Bonneville basin are in phase with large-scale climate change events. Close synchroneity of Bonneville lake events with Asian and East Asian monsoon intensity fluctuations during the last deglaciation also illustrates that the Bonneville basin lake system was highly sensitive or responsive to hemispheric scale, abrupt climate change events.