Eruption Rates, Tempo, and Stratigraphy of Paleocene Flood Basalts on Baffin Island, Canada.

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. Plain Language Summary: Lavas erupted about 60 million years ago on Baffin Island, Canada, are well studied by geochemists because they are thought to derive from the Iceland mantle plume. However, the age and eruptive frequencies of the flows are not well known. We report geologic observations from seven packages of lava flows and present paleomagnetic data from 38 sites. We calculate that at least 0.035 km3 of lava was being produced every year during the volcanic episode. Based on the paleomagnetic data, all the flows erupted in less than five thousand years with an average of 67 years between eruptions. This is consistent with results from similar lavas in West Greenland, which likely erupted at the same time. For unknown reasons, the Baffin Island and West Greenland eruptions did not cause a mass extinction but may have caused a global warming event. Key Points: New stratigraphic and paleomagnetic data are presented from flood basalts on Baffin Island, CanadaThe exposed lavas erupted in less than 5,000 years, with an average eruption interval of 67 yearsMinimum long‐term eruption rates were less than rates found in larger flood basalt provinces [ABSTRACT FROM AUTHOR]