Mid-Cretaceous High Arctic stratigraphy, climate, and Oceanic Anoxic Events

Abstract

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.

Mid-Cretaceous carbon cycle perturbations and Oceanic Anoxic Events recorded in southern Tibet

“…Based on the similar variation trends we correlated our δ 13 C org curve in the Cheqiela section with the age-calibrated reference δ13C carb curve in Europe compiled by Jarvis et al 3. and Herrle et al 13. (Fig.…”

“…This positive δ 13 C org excursion and the following relatively high value interval can be correlated to the late Aptian cold snap (Fig. 1F)61113. A large negative δ 13 C org excursion, from −24.1‰ to −26.7‰, at the boundary between the Dongshan Formation and the Chaqiela Formation follows this cold snap.…”

“…Organic biomarker data indicate that the sedimentary organic matter in Gamba area was mainly derived from marine algae2728, which precludes the possibility that the δ 13 C org excursions were caused by the variation of organic matter sources. Based on the similar variation trends we correlated our δ 13 C org curve in the Cheqiela section with the age-calibrated reference δ13C carb curve in Europe compiled by Jarvis et al 3. and Herrle et al 13.…”

“…The carbon isotope excursions in carbonate and organic carbon had recorded these carbon cycle changes and can be faithfully used to mid-Cretaceous stratigraphic correlation1578. A large number of mid-Cretaceous C-isotope curves have been reported during the past decades378910111213. However, most studies were focused on the western Tethys, Atlantic, Western Interior Seaway, and Pacific, whereas only a few high resolution carbon isotope curves from eastern Tethys were presented8141516.…”

A brief warming event in the late Albian: evidence from calcareous nannofossils, macrofossils, and isotope geochemistry of the Gault Clay Formation, Folkestone, southeastern England

“…Our understanding of Albian palaeoclimates largely comes from studying short-term perturbations in the global carbon cycle, known as oceanic anoxic events 1b, 1c, and 1d (e.g., Leckie et al, 2002;Galeotti et al, 2003;Giraud et al, 2003;Herrle et al, , 2004Jenkyns, 2010;Coccioni et al, 2014) using geochemical data (carbon and oxygen isotopes) and often related to biotic turnovers among marine planktonic and benthic organisms from pelagic deep-sea drilling sites and/or the proto-North Atlantic and western Tethys epicontinental basins (e.g., Erbacher et al, 1999;Herrle and Mutterlose, 2003;Watkins et al, 2005;Wagner et al, 2007Wagner et al, , 2008Huber and Leckie, 2011;Friedrich et al, 2012). Studies have also extended to the high Arctic (Herrle et al, 2015) and the eastern Tethys in China (Li et al, 2016). Short-term disruptions to this warm and equable climate mode have been suggested, including interludes of global cooling ("cold snap") around the AptianAlbian transition (Pirrie et al, 2004;Mutterlose et al, 2009;McAnena et al, 2013) and brief warming events in the late Albian (Erbacher et al, 2011;Friedrich et al, 2012).…”