I study the connections between the evolution of Earth-system processes, biological innovation, and ecosystem change—foremost in Earth’s early history. My research integrates field, petrographic, and geochemical work. The protracted rise of oxygen over several billion years dramatically changed Earth’s surface environments. However, our current picture of Earth’s redox evolution is still painted with only broad strokes. A central theme of my research has been trying to piece together the history and effects of Earth’s oxygenation. With that end goal in mind, I am currently working on coupling paleoredox proxies in Precambrian sedimentary rocks, calibrating novel metal isotopes systems in modern aqueous systems, and untangling the distribution and diagenetic history of traces metals in sedimentary rocks.
I am interested in understanding the interactions between tectonics, climatic processes and geochemical cycles on a range of time scales. I use radiogenic isotope geochemistry, in particular the rhenium-osmium (Re-Os) geochronometer, Sr and Nd isotopes combined with field-based mapping, sedimentology, stratigraphy and mineralogy to interrogate the rock record of critical transitions in Earth history. My near term research interests are centered on four main areas: 1) refining Earth history records, especially Proterozoic tectonic reorganizations and eukaryotic diversification, 2) combining geochemical proxies with microfossil and sedimentological analyzes to provide better constraints on ice sheet dynamics over the last 5 million years, 3) understanding hydrocarbon systems and ore genesis through the use of geochronology and geochemistry, and 4) integrating the Re-Os geochronometer into the EARTHTIME organization and leading an international effort for inter-laboratory standardization.
Associate Research Scientist
I have operated the MC-ICP-MS machine under various projects and measuring a large variety of isotopic systems (e.g., Si, Fe, Ni, Cu, Mo, Nd, Sm and Pb). The work has included collaboration with scientists from IFREMER and from other research institutes and universities. Development and calibration of isotopic measurements by laser ablation MC-ICP-MS methods. Guiding students in all aspects of clean lab work and isotopic measurements.
Studying Mo isotopes (and possibly other metallic isotope systems) of Mesoproterozoic - Neoproterozoic sediments from the Mbuji-Mayi Supergroup of Congo. The ca. 1300 – 800 Ma Mbuji-Mayi Supergroup is associated with great climatic and biological changes also linked to the assembly (~ 1000 Ma) and break-up (~ 850 Ma) of Rodinia. In this project I attempt to reconstruct the paleo-redox conditions of the ocean and atmosphere during this time window using isotopic compositions of metallic elements. Other aspects of this project include the study of microfossils, carbon and oxygen isotopes and TOC.
Postdoctoral Fellow - Joint Hull-Planavsky Labs
My research focuses on the interplay between Earth’s climate and the fluxes of carbon from the lithosphere into the atmosphere, ocean, and finally into sediments. As the oceans represent the largest surficial reservoir of carbon, characterizing the marine carbon cycle is crucial to understanding the long-term regulation of atmospheric and climate.2
Leslie (Jamie) Robbins
Donnelley Environmental Postdoctoral Associate
My research is focused on understanding how sedimentary archives, such as banded iron formations, shales, and other chemical sediments, can be used to assess changes in surface environments over Earth’s 4-billion-year history. I’m particularly interested in how these changes either drive or respond to biological evolution and the development of novel geochemical proxies to assess past climate variability. Additional areas of interest include the biogeochemical cycling of trace elements, geobiology in ancient and modern environments, and particle surface reactivity.
I work mainly on geochemistry of sediments and biogeochemical modelling. Through geochemical analysis on both modern and ancient sediments as well as model works, I’m trying to understand whether the ancient rock records can capture the seawater chemistry and how the long-term changes in seawater chemistry can be linked with crust dynamics, biological renovation and atmospheric evolution.
Flint Postdoctoral Fellow
Experimental geochemistry utilizing isotopic techniques to better understand water-rock interactions associated with atmosphere-ocean CO2 buffering mechanisms.
My research now focuses mainly on the redox history of Precambrian seawater and atmosphere and its internal relationship with and huge impacts on the appearance and evolution of the early life on Earth. Specifically, on the basis of integrated field investigation and petrography, I apply non-traditional isotopic tracers (e.g., Cr, Fe, and Cu) on chemical sedimentary rocks (marine carbonate rocks and iron formations/ironstones) to solve the most puzzling questions relevant to oxygenation of our early earth.
Joachim (Jo) Katchinoff
I am interested in answering fundamental questions about the carbon cycle, weathering dynamics, biogeochemical cycles and the interplay between all of these processes in determining climate regulation in Earth’s past. Through the use of geochemical and experimental tools, coupled with numerical modelling, my goal is to better understand the intricacies of Earth’s weathering feedbacks and elucidate the factors that ultimately govern habitability.
My research uses techniques from sedimentology and geochemistry to answer questions about the coupled evolution of biogeochemical cycles and life during Earth’s history, primarily in the Proterozoic where our understanding of these processes is sparse. Examples include using trace metal isotope proxies to assess oxygenation of marine environments, field measurements to examine the early silica cycle, and examining fossils of early lifeforms.
I study the coevolution of life, climate, and biogeochemical cycles across Earth history via sedimentological and stratigraphic fieldwork, geochemical analysis, and numerical modelling. I am particularly interested in the role that metabolic and ecological innovations have played in shaping biogeochemical cycles, from the advent of oxygenic photosynthesis in the Archean to sediment mixing by burrowing animals in the Phanerozoic.