[2016] Coherent multi-archive dating: methodological development and application on the last deglaciation in the Mediterranean region

Coherency between chronologies from different climate archives has always been a major limitation for discussing the timing of proxy changes. Comparisons are made based on records presented either on their original chronologies, eg. independent dating methods, or after tuning under the usual climatic assumptions, eg. synchronous climate changes. However, such methods lead to large chronological uncertainties that prevent the proper discussions of leads and lags of key changes recorded by climate proxies.

The Datice dating tool was initially developed for the coherent dating of ice cores. Within the labex L-IPSL, it has been further developed and adapted to other paleoclimate archives such as sediment cores and speleothems (Lemieux-Dudon et al., 2015) and is now available at https://datice-multi-archives.ipsl.fr/. The major advantage of Datice for multi-archive coherent dating exercises resides in its capacity of dealing with uncertainties, both on the relative and absolute points of view. Such a tool permits to properly assess the uncertainty of the tuning methods and then the coherency between the different climate records.

We validate the use of Datice for multi-archive dating through an application focusing on the last Deglaciation in the Mediterranean region. We integrate records from lake sediments (Monticchio, Tenaghi Phillipon, Ohrid), a marine core (MD90-917) and speleothems (Sofular, Soreq, La Mine). Thanks to the identification of common tephra layers, we were able to build a common continental-marine chronological framework covering the last deglaciation.

References:

Lemieux-Dudon, B., Bazin, L., Landais, A., Toyé Mahamadou Kele, H., Guillevic, M., Kindler, P., Parrenin, F., and Martinerie, P.: Implementation of counted layers for coherent ice core chronology, Clim. Past, 11, 959-978, doi:10.5194/cp-11-959-2015, 2015.

Bazin L., Lemieux-Dudon B., Siani G. Landais A., Bassinot F., Genty D., Govin A., Michel E., Nomade S. and Waelbroeck C., A method for coherent multi-archive dating with objective error calculation: application to the last Deglaciation in the Mediterranean region, EGU, Vienna, April 2016; Q10, Bordeaux, February 2016.

Figure: The last deglaciation in the Mediterranean region compared with NGRIP d18O record. The different climatic records are presented on their original chronologies (grey) and on the coherent chronology obtained with Datice (red). The tuning points (top bars) are based on volcanic matching.