Eruption rates, tempo, and stratigraphy of Paleocene flood basalts on Baffin Island, Canada

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biasi, J., Asimow, P., Horton, F., & Boyes, X. Eruption rates, tempo, and stratigraphy of Paleocene flood basalts on Baffin Island, Canada. Geochemistry, Geophysics, Geosystems, 23(9), (2022): e2021GC010172, https://doi.org/10.1029/2021gc010172.High-temperature melting in mantle plumes produces voluminous eruptions that are often temporally coincident with mass extinctions. Paleocene Baffin Island lavas—products of early Iceland mantle plume activity—are exceptionally well characterized geochemically but have poorly constrained stratigraphy, geochronology, and eruptive tempos. To provide better geologic context, we measured seven stratigraphic sections of the volcanic deposits and collected paleomagnetic data from 38 sites in the lavas and underlying Cretaceous sediments (Quqaluit Fm.). The average paleomagnetic pole from this study does not overlap with the expected pole for a stable North American locality at 60 Ma, yet the data have sufficient dispersion to average out secular variation. After ruling out other possibilities, we find that the picrites were probably erupted during a polarity transition, over less than 5 kyr. If so, the average eruption interval was ∼67 years per flow for the thickest sequence of exposed lavas. We also calculate that the flood basalts had a minimum total volume of ∼176 km3 (excluding submerged lavas in Baffin Bay). This implies a minimum eruption rate of ∼0.035 km3 yr−1, which is similar to rates found in West Greenland lavas but less than rates found in larger flood basalts. Despite this, the Baffin and West Greenland lavas temporally correlate with the “End C27n event” (a period of ∼2°C global warming) and may be its underlying cause.his work was supported by the National Science Foundation (award #1911699 to F. Horton and award #2052963 to J. Biasi), Woods Hole Oceanographic Institution (WHOI) Andrew W. Mellon Foundation Endowed Fund for Innovative Research, a National Geographic Society grant (#CP4-144R-18), and internal funding from the Caltech Geological and Planetary Sciences Division