Updated 8/30/99
Base Map Information
The map projection used in the Beringian Section is an Equirectangular Projection (a.k.a. La Carte Parallélogrammatique or Die Rechteckige Plattkarte) with standard parallels of 60°N and 60 °S. Given these standard parallels, our Beringian map is scaled such that one degree of latitude equals two degrees of longitude. The topography is generated from five minute gridpoint elevations (ETOPO5) data from the GETECH CD-ROM (Department of Earth Sciences, University of Leeds).
Our paleocoastline data are generated in two ways. The simplest reconstruction we have is based on the modern topography and bathymetry, and uses past changes in the global eustatic sea-level (Bard et al., 1996) to generate a coastline by lowering sea level. This approach assumes no changes in basin morphology have occurred over the last 18,000 years. Our second approach is the application of radiocarbon dated horizons on the continental shelf to estimate sea level at several times during deglaciation. The resulting maps are then fitted into the eustatic sea level model to create one that combines the data based reconstruction with the global eustatic sea level curve.