| Due to their outstanding resolution and well-constrained chronologies, Greenland ice core
records have long been used as a master record of past climatic changes during the last
interglacial-glacial cycle in the North Atlantic region. As part of the INTIMATE (INtegration
of Ice-core, MArine and TErrestrial records) project, protocols have been proposed to ensure
consistent and robust correlation between different records of past climate. A key element of
these protocols has been the formal definition of numbered Greenland Stadials (GS)
and Greenland Interstadials (GI) within the past glacial period as the Greenland
expressions of the characteristic Dansgaard-Oeschger events that represent cold and warm
phases of the North Atlantic region, respectively. Using a recent synchronization
of the NGRIP, GRIP, and GISP2 ice cores that allows the parallel analysis of all
three records on a common time scale, we here present an extension of the GS/GI
stratigraphic template to the entire glacial period. This is based on a combination of
isotope ratios (δ18O, reflecting mainly local temperature) and calcium concentrations
(reflecting mainly atmospheric dust loading). In addition to the well-known sequence of
Dansgaard-Oeschger events that were first defined and numbered in the ice core records
more than two decades ago, a number of short-lived climatic oscillations have been
identified in the three synchronized records. Some of these events have been observed
in other studies, but we here propose a consistent scheme for discriminating and
naming all the significant climatic events of the last glacial period that are represented
in the Greenland ice cores. This is a key step aimed at promoting unambiguous
comparison and correlation between different proxy records, as well as a more
secure basis for investigating the dynamics and fundamental causes of these climatic
perturbations.
The work presented is under review for publication in Quaternary Science Reviews. Author
team: S.O. Rasmussen, M. Bigler, S.P.E. Blockley, T. Blunier, S.L. Buchardt, H.B. Clausen†,
I. Cvijanovic, D. Dahl-Jensen, S.J. Johnsen†, H. Fischer, V. Gkinis, M. Guillevic, W.Z.
Hoek, J.J. Lowe, J. Pedro, T. Popp, I.K. Seierstad, J.P. Steffensen, A.M. Svensson, P.
Vallelonga, B.M. Vinther, M.J.C. Walker, J.J. Wheatley, and M. Winstrup (†: deceased). |