Overview


Cambrian and Ordovician strata of the Upper Mississippi Valley region provide robust targets for geochemical analyses due to their relative lack of sedimentary burial and benign diagenetic history. Clumped-isotope (Δ47) analyses of Hirnantian-age strata in this area, combined with results from coeval successions in Anticosti Island, have provided constraints on the magnitude and duration of the Late Ordovician-Early Silurian glaciation.

Proterozoic strata from northern Minnesota and Ontario record the deposition of a 1.88 Ga pulse of iron formation and the dominance of a unique biological community. Work with the Bergmann Lab focuses on the use of field observations, analyses of microfossil assemblages, and geochemical proxies to constrain the tectonic setting of this region in order to better understand the basin-scale dynamics of iron formation deposition.

Publications

Bergmann, K.D., Finnegan, S., Creel, R., Eiler, John M., Hughes, N.C., Popov, L.E., Fischer, W.W.; A paired apatite and calcite clumped isotope thermometry approach to estimating Cambro-Ordovician seawater temperatures and isotopic composition: Geochimica et Cosmochimica Acta, v. 224, 18-41.

Finnegan, S., Bergmann, K., Eiler, J.M., Jones, D.S., Fike, D.A., Eisenman, I., Hughes, N.C., Tripati, A.K., Fischer, W.W., 2011, The magnitude and duration of Late Ordovician–Early Silurian glaciation, Science, v. 331, p. 903-906.