Onset of strong Iceland-Scotland overflow water 3.6 million years ago
Abstract
Abstract North Atlantic Deep Water (NADW), the return flow component of the Atlantic Meridional Overturning Circulation (AMOC), is a major inter-hemispheric ocean water mass with strong climate effects but the evolution of its source components on million-year timescales is poorly known. Today, two major NADW components that flow southward over volcanic ridges to the east and west of Iceland are associated with distinct contourite drift systems that are forming off the coast of Greenland and on the eastern flank of the Reykjanes (mid-Atlantic) Ridge. Here we provide direct records of the early history of this drift sedimentation based on cores collected during International Ocean Discovery Programme (IODP) Expeditions 395C and 395. We find rapid acceleration of drift deposition linked to the eastern component of NADW, known as Iceland–Scotland Overflow Water at 3.6 million years ago (Ma). In contrast, the Denmark Strait Overflow Water feeding the western Eirik Drift has been persistent since the Late Miocene. These observations constrain the long-term evolution of the two NADW components, revealing their contrasting independent histories and allowing their links with climatic events such as Northern Hemisphere cooling at 3.6 Ma, to be assessed.
Article Details
Authors (36)
Matthias Sinnesael
Boris-Theofanis Karatsolis
Paul N. Pearson
Department of Earth Sciences, University College London
Anne Briais
Sidney R. Hemming
Leah J. LeVay
Tom Dunkley Jones
Ying Cui
Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine
Anita Di Chiara
Justin P. Dodd
Deepa Dwyer
Deborah E. Eason
Sarah A. Friedman
Emma Hanson
Katharina Hochmuth
Australian Centre of Excellence in Antarctic Science
Halima E. Ibrahim
Claire E. Jasper
Saran Lee-Takeda
Danielle E. LeBlanc
Melody R. Lindsay
David D. McNamara
Sevasti E. Modestou
Margaret A. Morris
Bramley J. Murton
Suzanne OConnell
Gabriel Pasquet
Sheng-Ping Qian
Yair Rosenthal
Department of Marine Sciences, Rutgers University
Sara Satolli
Takuma Suzuki
Thena Thulasi
Bridget S. Wade
Department of Earth Sciences, University College London
Nicholas J. White
Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand
Tao Wu
Alexandra Y. Yang
Ross E. Parnell-Turner