The Australasian INTIMATE Project
OBJECTIVE:
• Identify and prioritise Australian onshore
and offshore reference records for the OIS 2/1 transition.
• Promote ways to effect high-precision and
dating of key Australian onshore and offshore records for the determination
of a regional event stratigraphy.
Background
Since 1997, INTIMATE (INTegration of Ice-core, Marine and TErrestrial
records – a core programme of the INQUA (International Union for Quaternary
Research) Palaeoclimate Commission) project members have, through a series
of international workshops, sought ways to improve procedures for establishing
the precise ages of, and effecting high-resolution correlations between
North Atlantic climate events of the Last Termination. There have been two
major driving forces behind this. First was the publication of the GRIP and
GISP2 ice-core record (Alley et al. 1993; Johnsen et al. 2001), which showed
that environmental changes during the Last Termination were more abrupt
and complex than had been previously been realised. They demonstrated the
need for methods that enabled the sequence of events during the Last Termination
to be reconstructed at the decadal time–scale. The second was the growing
realisation of the severity of the difficulties that affect radiocarbon dates,
the method most widely used to date the Last Termination events. North Atlantic
INTIMATE members have therefore proposed a number of ways by which clarity
and precision might be improved, and these include an event stratigraphy
basis for correlation (Bjorck et al. 1998; Walker et al. 1999; Lowe et al.
2001), improved protocols for radiocarbon dating (e.g. Wohlfarth 1996; Lowe
and Walker 2000) and tephrochronology (Turney et al. 2004), correlation based
on stratigraphical methods thought to reflect synchronous regional or global
changes (e.g. oxygen isotope stratigraphy; Hoek and Bohncke 2001) and more
effective use of sites with annually laminated sediment sequences (e.g.
Litt et al. 2001).