Quantifying the on-going isostatic signal along the World's coastlines. A key information to assess current and future sea-level changes.
Reconstructions of relative sea level (RSL) have implications for investigation of crustal movements, calibration of earth rheology models and the reconstruction of ice sheets. In recent years, efforts were made to create RSL databases following a standardized methodology. These regional databases provide a framework for developing our understanding of the primary mechanisms of RSL change since the Last Glacial Maximum and a long-term baseline against which to gauge changes in sea level during the 20th century and forecasts for the 21st.
The seminar will present the results of recently compiled databases in very different climatic and geographic contexts that are the Atlantic and Pacific coast of North America, the Mediterranean Sea and the south-east Asian coasts.
The re-evaluation of sea-level indicators from geological and archaeological investigations have yielded more than 3000 RSL data-points mainly from salt and freshwater marshes or adjacent estuarine sediment, isolation basins, beach ridges, fixed biological indicators, beachrocks as well as coastal archaeological structures. Some of the inherent difficulties, and potential solutions to analyse sea-level data in such different depositional environments will be outlined. In particular, problems related with the definition of standardized indicative meaning (i.e., the relationship between the indicator and the paleo mean sea level), and with the re-evaluation of old radiocarbon samples. The presentation will further address complex tectonics influences and the framework to compare such large variability of RSL data-points. Finally, the implications of these results for the patterns of glacio-isostatic adjustment (GIA) in these regions will be discussed.