Bergmann Lab

The Bergmann Lab’s multi-disciplinary research – sedimentology and stratigraphy, stable isotope geochemistry of carbonates including clumped isotope thermometry, and geobiology – focuses on reconstructing the record of environmental change from observations of sedimentary rocks spanning Precambrian to end-Ordovician time. Current work in the Bergmann Lab is focused on interpreting the record of marine carbonate sedimentary rocks and fossils. We analyze these rocks using a variety of tools in order to better understand how the chemistry and climate of the oceans and atmosphere affected the evolution of complex life, from unicellular microbial communities to multicellular animal communities. Our research attempts to place constraints on the environmental change that provides a backdrop for early evolution and quantify the range of climatic conditions the earth system is capable of.

All projects begin in the field. We make detailed observations of the character of ancient marine sedimentary rocks including variations in microbial textures and patterns of sea level change using traditional field techniques as well as new technologies, such as drones. In the lab we use microscopes to look at minerals precipitated out of ancient oceans and microfossils too small to see with the naked eye. To better constrain seawater chemistry and later alteration during burial (diagenesis), we look for small changes in the chemistry and structure of carbonate fabrics using micro-analytical techniques. Many of our projects also use a method to get at ancient changes in climate, clumped isotope thermometry, that measures two heavy isotopes 13C and 18O in marine carbonate and apatite fossils and rocks. We have also begun exploring using databases to quantify changes in marine carbonates over longer timescales and broader areas.

Active research questions are:
(*) The nature of large negative carbon isotope excursions in the Neoproterozoic including the Shuram, Bitter Springs and Islay anomalies
(*) Significance of δ18O changes through time in the Neoproterozoic, Cambrian and Ordovician and the evolution of climate and the δ18O of seawater
(*) Patterns and variations in carbonate sedimentation across the Precambrian and Cambrian
(*) Diagenesis in marine Precambrian carbonate rocks
(*) Trends in the early evolution of complex life using microfossils and biomarkers
(*) Climate-weathering feedbacks in the Neoproterozoic