A New Inverse Method to Construct a Common and Optimal Ice Chronology for EPICA Ice Cores

Ice-cores dating is an essential issue to analyse data measured on ice samples in order to contribute to Earth climate history decephering. Several methods have been already implemented. Each method brings some valuable but incomplete information for building the depth-age relationship of an ice-core: some methods only apply on the top part of the core (e.g., annual layer counting) while others apply on the whole core (e.g. orbital tuning), some methods are accurate for absolute ages (e.g. absolute age markers) while others are accurate for events duration (e.g. ice flow modelling). Moreover, stratigraphic markers (e.g. volcanic horizons) bring additional information on the ice flow and allow to link the age scales of distinct cores. The aim of this study is to use an inverse method to gather this fragmented information. The new inverse method is based on the assumption of a non-deterministic ice flow model. It allows to construct a common and optimal age scale for several ice cores and to estimate its confidence interval.