Output details

Relative sea-level fall since the last interglacial stage: Are coasts uplifting worldwide?

This paper synthesises published data from as many sources as could be compiled, with unreliable ones excluded from the analysis. The results were also compared with major papers that address the subject. The paper focuses on data from the last interglacial highstand, approximately 125,000 years ago (called MIS5e), because the sea level at MIS5e is recognized to be higher than present, so that preserved shorelines from that time are sufficiently common to allow a comprehensive data assembly and analysis. The data are processed in relation to known processes across the continental margins, for which there is a lot of published research (applied in this paper) that demonstrates the modern understanding of tectonic and tectonic-related processes appropriate to constrain the results with confidence.

The overall trend extracted from the data demonstrates that locations on the world’s coastlines undergoing long-term uplift are much more abundant than those places where the coastline is subsiding. This major outcome is considered the result of the overall long-term geological trend towards continental assembly in many continental masses, the lateral compressive processes of which generate uplift. Uplift is greater on active continental margins where subduction operates, because compressive stress there leads to greater vertical movement on the margins; this is demonstrated in the summary map in Figure 3.

A further outcome of this work is that the mean uplift of the MIS5e shorelines is much greater than recent estimates by other workers, at 28 m, approximately four times greater than the quoted paper by Kopp et al. (2009). Kopp et al. used 42 localities to generate their estimates, compared to 890 localities in Pedoja et al. This paper therefore presents the most comprehensive attempt to assess MIS5e sea levels, and leads to the conclusion of high global uplift. Results were reported in Geoscientist, September 2011.