We are using the triple isotopes of oxygen of hydrothermally altered rocks to determine the isotope composition of meteoric waters that interacted with the Idaho Batholith in the Eocene. This approach allows us to reconstruct the paleoelevation of the crystalline core on the Rocky Moutains. It also allows us to understand hydrogen isotope exchange mechanisms when we compare the triple oxygen isotope analysis with paired hydrogen and oxygen isotopes of water bearing minerals (Chamberlain et al., in review).
The remnants of expansive lake systems that previously covered the western United States are clear evidence that the region now known as the "desert west" has not always been so deserted. During past intervals of both warmer-than-modern and colder-than-modern conditions large lakes covered much of the west. We are evaluating the climatic conditions that provide enough water to support lakes in such opposing climate states. See our work in Geology comparing lake dynamics of the Last Glacial Maximum and Mid-Pliocene (Ibarra et al., 2018).
Transition to grass-dominated landscapes during the Neogene dramatically changed the recycling of water vapor, ushering in the modern hydrologic regime. We are examining the relationship between changes in vegetation cover and concurrent climate change. See our most recent papers in Earth and Planetary Science Letters (Mix et al., 2013) and Global Biogeochemical Cycles (Chamberlain et al., 2014).
Because of the need to understand the links and feedbacks of the carbon cycle during times of global greenhouse we are examining the Cretaceous climate record preserved in lake sediments in northern China. Along with our long-term collaborator, Professor Stephan Graham (Dept. Geological and Environmental Sciences, Stanford) we are using the stable isotopes of ostracod valves from drill cores in the Songliao basin to reconstruct climate records.