A FIRST LOOK AT NEW CHIRP SEISMIC REFLECTION PROFILES FROM JACKSON LAKE (GRAND TETON NATIONAL PARK)

Jackson Lake is the crown jewel in a series of spectacular range-front lake basins in Grand Teton National Park (Wyoming, USA). An exorheic terminal moraine lake that was volumetrically modified in 1916 CE with the emplacement of Jackson Lake dam, Jackson Lake collects water and sediment from the Snake River on its northern axis, as well as major transverse Teton Range drainages on its western margin. We view the Jackson Lake depositional system as a sensitive archive of surficial processes and environmental changes affecting the Teton Range over time scales ranging from 10¹-10⁴ yrs. The lake and its sediments have been studied for several decades, but until recently subsurface seismic images have been unavailable. We present high-resolution CHIRP seismic profiles from a lake-wide survey of Jackson Lake completed in 2018 under permitting from the U.S. National Park Service. Data quality are excellent across the basin, and seismic profiles illustrate the influences of glacial activity, faulting, earthquakes, climatically induced water level changes, and human impacts on the stratigraphy. Integrating limnogeological datasets from Jackson Lake with insights derived from low temperature thermochronological and structural analyses of the Teton Fault provide an opportunity to holistically assess the processes and rates controlling the geomorphological evolution of Grand Teton National Park.