science activities

cct 1 - chronology
rationale

Every proxy record needs an age assignment before it can be used for paleoclimatic research. The age can be derived from absolute radiometric dating or from comparison of the proxy record with a master curve. In either case, age models must be based on approaches clearly defined and established in conventions worldwide.

Model-data comparisons need records on a common absolute timescale at least with a resolution of a century, better a decade.

The major events of climate change are teleconnected globally, but with lags and leads between regions and in the response of environment and vegetation. A common chronology needs to include the complexity of Earth system dynamics but at the same time provide a reliable master chronology.

There are numerous national and international projects, working groups, coordinated programs and commissions (e.g. INQUA) to improve the above demands. PAGES strongly encourages all of this work. However, it appears sometimes problematic to come to an integration of the different stratigraphic and chronological efforts. It is the intention of PAGES to stimulate a series of workshops and symposia during the next 5 years to progress on the accuracy and precision of individual dating techniques and to reach an integration of the different chronological and stratigraphical approaches.

goals

1. A re-evalution of the insolation curves and an extention of the SPECMAP timescale down to the beginning of the Quaternary.

2. A high resolution sea-level master curve.

3. Narrowing down of the uncertainty for existing radiometric dating methods.

4. Improvement of calibration techniques. This applies mainly for ¹⁴C calibration curves using tree rings, sediment varves, and other archives.

5. New dating methods for the time beyond U/Th, i.e. older than about 300,000 years.

6. A paleomagnetic master curves for all parts of the globe including also short term events.

7. A synthesis of well-dated tephra on land and in the ocean with ice core record.

8. A summarized event chronology (e.g. Heinrich layers, IRD events, dust spikes, methane outbursts, super El Ninos, etc) for ice, land and ocean, integrated as a “PAGES Table of Quaternary Chronology”.



PLEASE NOTE: This is draft text pending publication of PAGES Science Plan and Implementation Strategy.