People on the Earth History team

Anne-Sofie Ahm, incoming Assistant Professor (CV)

As an Earth Historian, I am interested in how we can use the chemistry of rocks to gain insight into the surface conditions of Earth in the past. The chemistry of marine carbonate sediments has been used to reconstruct the evolution of global biogeochemical cycles for a wide range of elements throughout the entirety of Earth history. However, one of the main limitations in using this geochemical archive is the susceptibility of carbonate sediments to diagenesis, as unlithified sediments are transformed into the rocks we can study in the geological record. Using multiple isotope systems and numerical models of diagenesis, my research seeks to extract the primary chemical information from ancient carbonate sediments by better understanding the diagenetic processes. I am particularly interested in the co-evolution of climate and life during fundamental transitional periods in Earth history such as the Great Oxidation Event, Neoproterozoic Snowball Earth events, the Cambrian explosion of animal life, and the end-Ordovician mass extinction.

Daniel Garduño, PhD candidate

I am interested in investigating the interactions of climate, atmospheric chemistry, and geologic processes through Earth History. Specifically, my research focuses on the effects of the Great Oxidation Event on climate and atmospheric chemistry. The Great Oxidation Event fundamentally changed the Earth's surface redox conditions, increasing the atmosphere's oxygen content and affecting the Earth's biochemical cycles. Multiple lines of evidence suggest that the Earth suffered a period of climatic upheaval after the Great Oxidation Event, going from periods of global glaciations to periods of stability. My research tries to understand why climate behaved like this after the Great Oxidation Event and how these changes in climate could have affected the atmospheric chemistry of the Earth and vice versa. I am using a combination of photochemical, climate and simple mass balance models to try to understand these problems.