PICE Talk by Michael Dyonisius

Using ancient ice from Taylor Glacier, Antarctica to study the past methane budget and in situ cosmogenic 14C production rates in ice

Ablation sites such as Taylor Glacier, Antarctica provide easy access to near unlimited amount of old ice core samples. Methane isotopes measurements (14CH4, δ13CH4, and δD-CH4) were conducted on samples from Termination 1 (18-8.2 kyr BP). From the 14CH4 data, we show that emissions from old carbon reservoirs (natural geologic emissions, marine hydrates, and old permafrost) were small (<19 Tg CH4/yr, 95% confidence interval) throughout the deglaciation. From the stable isotopes data, we show that CH4 emissions from biomass burning during the preindustrial Holocene were comparable to today (22-56 Tg CH4/yr, 95% confidence interval). We also collected samples with ages older than >50 kyr BP for 14CO, 14CO2, 14CH4 measurements to calibrate the production rates of in situ cosmogenic 14C from muon reactions and find that the literature values of muogenic 14C production rates (Heisinger et al.,2002a, 2002b) are overestimated by factors of 4 to 5.

All are welcome to join the seminar by using the Zoom link: https://ucph-ku.zoom.us/j/69832992696