Mid-cretaceous high arctic stratigraphy, climate, and oceanic anoxic events
Over the past decades, much research has focused on the mid-Cretaceous greenhouse climate, the formation of widespread organic-rich black shales, and cooling intervals from low- to mid-latitude sections. Data from the High Arctic, however, are limited. In this paper, we present high-resolution geochemical records for an ~1.8-km-thick sedimentary succession exposed on Axel Heiberg Island in the Canadian Arctic Archipelago at a paleolatitude of ~71°N. For the first time, we have data constraints for the timing and magnitude of most major Oceanic Anoxic Events (OAEs) in brackish-water (OAE1a) and shelf (OAE1b and OAE2) settings in the mid-Cretaceous High Arctic. These are consistent with carbon-climate perturbations reported from deep-water records of lower latitudes. Glendonite beds are observed in the upper Aptian to lower Albian, covering an interval of ~6 m.y. between 118 and 112 Ma. Although the formation of glendonites is still under discussion, these well-dated occurrences may support the existence of cool shelf waters in the High Arctic Sverdrup Basin at this time, coeval with recent geochemical data from the subtropical Atlantic indicating a drop in seasurface temperature of nearly 4 °C.
Herrle, J.O. (Jens O.), Schroder-Adams, C, Davis, W. (William), Pugh, A.T. (Adam T.), Galloway, J.M. (Jennifer M.), & Fath, J. (Jared). (2015). Mid-cretaceous high arctic stratigraphy, climate, and oceanic anoxic events. Geology, 43(5), 403–406. doi:10.1130/G36439.1