Forging Signatures: Climate’s Limited Role in Shaping and Changing the Earth’s Surface
Jane Willenbring1 and Pedro Val2
1Department of Geological Sciences, Stanford University, Stanford, California, USA
2Department of Geology, Federal University of Ouro Preto, Ouro Preto, Brazil
How denudation at the Earth’s surface affects-and is affected by-climate remains a fundamental question in geoscience because of the influence of silicate weathering on climate and the potential role of climate in shaping landscapes. At the core of this question is a central hypothesis: if surface processes can erode the surface faster than tectonics can uplift topography over the timescale of mountain building, then highly efficient erosional processes which may be modulated by climate can affect mountain height and shape, and could enhance weathering product fluxes to oceans in the process.
In this talk, I’ll first provide context for a different (null) hypothesis driven by the observation that the 10Be/9Be ratios in Neogene seawater have been roughly constant, indicating the stability of continental denudation globally. I’ll then describe lessons learned and results from in situ-produced 10Be and meteoric 10Be by the cosmogenic nuclide community spanning the last decades. A synopsis of denudation rates and paleo-denudation rates derived from in situ-produced cosmogenic nuclides challenge the signatures of climate-driven geomorphic change in sediments and topography all around us. These past studies and new meteoric 10Be data hold some answers but also create critical, open questions about when and where climatic drivers take a backseat to tectonics.
Jane Willenbring is an Associate Professor of Geological Sciences at Stanford University. Her research examines the evolution of the Earth’s surface and uses cosmogenic nuclides to understand how landscapes are affected by tectonics, climate change, and life. She also organizes environmental justice campaigns around urban soil pollution and does outreach and education to try to reduce harassment and discrimination in STEM. She is a fellow of Geological Society of America and the recipient of numerous awards including the inaugural Marguerite T. Williams award from the American Geophysical Union. Dr. Willenbring is one of the scientists featured in the PBS | NOVA documentary film “Picture a Scientist” that is now available to watch on Netflix.