ESS Department - February 20th, 2020
G.K. Gilbert’s 1890 monograph on Lake Bonneville published by the United States Geological Survey initiated over a century of research on Quaternary lakes in the American west. The continuation of this work is increasingly pertinent today with the need to test climate models used to forecast future water resources in the region as the climate warms. Importantly the presence or absence of lakes in terminal basins provide the most unequivocal measure of wetness. In this work I will show that wetter conditions during both colder- and warmer-than-present periods in the past are recorded in shoreline and outcrop data from the latest Pleistocene and the middle-Pliocene. In conjunction with paleotemperature data, derived from pollen, macrofossil assemblages and carbonate clumped isotope measurements, I will show hydrologic scaling relationships implying that: 1) Pleistocene lakes during glacial maxima in the northern Great Basin do not require...
ESS Department - February 14th, 2020
There are 3 key elements of the cryosphere: ice sheets, permafrost and sea ice that are under existential threat by climate warming. A recent article in Nature argued that they were already past "tipping points", and that there was now essentially no time to manage their preservation due to the 30 year timescale to achieve net zero greenhouse gas emissions. However there are things that can be done to slow or reverse these losses to the cryosphere, and these provides hope that is crucial to societal engagement with the on-coming climate crisis. In this talk I will discuss possible interventions to conserve these elements, and how they may be co-designed between indigenous populations and engineers. I discuss simulations, engineering and economic costings as well as measures already underway, and how the progression of deployment may be managed over the coming decades.
ESS Department - February 6th, 2020
The interplay of tectonic and surface processes drives many societally relevant processes from seismic hazard at subduction zones to the construction of Earth’s largest mountains. The St. Elias Mountains in southern Alaska are the world’s highest coastal range, host the world’s two largest temperate glaciers and experience the highest recorded offshore sediment accumulation rates globally. Combined with high uplift rates and proximity to one the of the world’s most seismically active margins, the area provides a superb setting for evaluating competing influences of tectonic and surface processes on mountain-building. Before Integrated Ocean Drilling Program Expedition 341 in 2013, studies were limited by the absence of information on the time-dependent behavior of glaciers and faults. High precision age constraints from drilling show how fault activity across the offshore St. Elias Mountains varies through space and time. Following...