The Late Mesozoic‐Cenozoic Arctic Ocean Climate and Sea Ice History: A Challenge for Past and Future Scientific Ocean Drilling

Abstract

Over the past 3-4 decades, coincident with global warming and atmospheric CO 2 increase, Arctic sea ice has significantly decreased in its extent as well as in thickness. When extrapolating this alarming trend, the central Arctic Ocean might become ice-free during summers within about the next 2-5 decades. Paleoclimate records allow us to better understand the processes controlling modern climate change and distinguish between natural and anthropogenic forcing. In this context, detailed studies of the earlier Earth history characterized by a much warmer global climate with elevated atmospheric CO 2 concentrations are important. The main focus of this review paper is the long-term late Mesozoic-Cenozoic Arctic Ocean climate history from Greenhouse to Icehouse conditions, with special emphasis on Arctic sea ice history. Starting with some information on the Cretaceous Arctic Ocean climate, this paper will concentrate on selected results from Integrated Ocean Drilling Program (IODP) Expedition 302 (Arctic Ocean Coring Expedition (ACEX)), the first scientific drilling in the permanently ice-covered Arctic Ocean, dealing with the Cenozoic climate history. While these results from ACEX were unprecedented, key questions related to the Cenozoic Arctic climate history remain unanswered, largely due to the major mid-Cenozoic hiatus (if existing) and partly to the poor recovery of the ACEX record. Following-up ACEX and its cutting-edge science, a second scientific drilling on Lomonosov Ridge with a focus on the reconstruction of the continuous and complete Cenozoic Arctic Ocean climate history has currently been proposed and scheduled as IODP Expedition 377 for 2021.

Alginite-Rich Layers in the Bazhenov Deposits of Western Siberia

“…A high content of type I kerogen is concentrated in luminescent Stellarites of Late Carboniferous within the Stellarton basin in Canada [89,90]. Algal-rich sediments of the Late Jurassic-Early Cretaceous age have been found in the southern part of the Barents Sea [91,92]. The Blackstone layer of the Late Jurassic Kimmeridge Formation consists primarily of algal origin OM [93,94].…”

Natural variability of the Arctic Ocean sea ice during the present interglacial

“…Moreover, the past 1,400 y only encompass a small fraction of the climate variations that occurred during the Cenozoic ( 7 , 8 ), even during the present interglacial, i.e., the Holocene ( 9 ), which began ∼11,700 y ago. To assess Arctic sea-ice instabilities further back in time, the analyses of sedimentary archives is required but represents a challenge ( 10 , 11 ). Suitable sedimentary sequences with a reliable chronology and biogenic content allowing oceanographical reconstructions can be recovered from Arctic Ocean shelves, but they rarely encompass more than the past 10,000 y because they remained emerged and subject to glacial erosion during most of the past ice age.…”

New Data on Stratigraphy and Distributions of Glendonites from the Carolinefjellet Formation (Middle Aptian–Lower Albian, Cretaceous), Western Spitsbergen

“…The Arctic basin, where the studied strata accumulated, represented a partially isolated basin at the beginning of the Cretaceous (Price and Nunn, 2010;Smith et al, 1994;Stein, 2019). Apparently, its waters were characterized by a lighter oxygen isotopic composition compared to that in the seawater of open basins.…”