Ecological inter-linkages between terrestrial and coastal environments in the Indian Western Pacific Region

Optically Stimulated Luminescence Dating of Coastal Sediments

 The effect of tsunamis on geology, geomorphology and ecology along the coastlines of India is investigated in this project. Tsunamis, cyclones or other events leave traces in coastal sediments, e.g. coastal dunes or beach sediments. Tsunamis in the Bay of Bengal are triggered by earthquakes. The dating and geochronology of the event layers gives information about the timing and the recurrence interval of strong earthquakes. Hence it is also possible to reconstruct the movement of the tectonic plates along the subduction zone in front of the Andaman and Nicobar Islands.

The study areas are located on Andaman Island and on the south-eastern coast of India south of Pondicherry. On the Andaman Islands coastal deposits are investigated. In south-east Indiacoastal dunes are investigated. The event layers and the surrounding sediment are dated with the Optically Stimulated Luminescence (OSL) Dating Method. With the OSL-dating method it is possible to determine the time passed since the last exposure of the sediment to sunlight. Hence it is possible to determine the age of deposition of the event layers. Additionally organic material is used for dating with radiocarbon. Young sediments from the mangroves are dated with lead-210. Sedimentological, mineralogical and geochemical analysis are also done to characterise the deposits.