Sea level reconstruction in the Beagle Channel, Chile: insights from coastal lakes and bogs

We lack any detailed information about the sea level history of southernmost Tierra del Fuego. To overcome this we have cored and analyzed sediments from two marine lagoons and five lakes/bogs along the northern shore of Isla Navarino and from one marine lagoon in the more central part of BC. The purpose of the study is to find the highest altitude for basins with marine sediments and to establish absolute ages of freshwater-marine transitions, so-called ingressions, and shifts from marine to freshwater conditions, so-called isolations, in the sediments. The ideal situation for a study like this is to work with sites situated on the same isobase, i.e. sites that have experienced the same uplift history. Due to the scarcity of suitable sites this is, however, not possible on Isla Navarino. Our sites are spread out from the westernmost (3 sites) part of the island, the central portion of the island (1 site) and more eastern sites (3). By combining our sites - from which we know the course of the sea level development (rising or falling) at a certain time - with other finds of marine indicators above today's sea level, e.g. 14C dated mollusc shells from sediment exposures, it will be possible to establish shore line diagrams for this part of BC and sea level curves for the areas with most 14C dated levels.

Leading PI: Prof. Svante Björck (University of Lund, Sweden).