XVI INQUA Congress

Paper No. 13
Presentation Time: 1:30 PM-4:30 PM

THE MALDIVES SEA LEVEL PROJECT. I: GENERAL OUTLINES


MÖRNER, Nils-Axel, Paleogeophysics & Geodynamics, Stockholm Univ, Stockholm, S-10691, Sweden, morner@pog.su.se

The INQUA Maldives Project started in 2000. Prior to that, quite little was know about the actual changes in past sea level in the Maldives. . With respect to multiple integrated sea level processes, the Maldives have a uniquely position (as described in Integrated Coastal Zone Management, No. 1, 2000, p. 17-20). Our team has undertaken two major expeditions plus a number of shorter visits in the Maldives. Our filed data includes extensive diving, reef ecology, coring marine lagoonal clay beds, coastal studies, coring fens and inland lagoons, levelling, sampling sea level index points, radiocarbon dating of some 35 samples, analyses of bones and pottery. The Maldives do not consist of predominantly catch-up coral reefs of Holocene age as previously proposed. On the contrary, the Maldives are predominantly formed by older reefs. The Last Interglacial level is at about +1.5-2.0 m (a reef body reaching –5 m is dated >40,000 BP). Flat inner-atoll areas in the order of –40–50 m seem to have been eroded by sea level variations during the isotopic stage 3 sea level with a cave at –29 m dated at about 27,000 BP. The LGM level seems to be deeper than usually at –150 m due to increased geoid relief during the last glaciation maximum (LGM). During this period the old reefs were strongly carstified. Paleogeographically, the LGM–Maldives consisted of a few large islands, most probably covered by tropical forests and traversed by drainage patterns and river systems. From 18,000 to 5000 BP, sea level rose episodically cutting submarine shorelines and coastal caves. Present sea level was reached at about 4500 BP. Sea level oscillated around the present in the last 4000 years. The subsequent development is discussed separately.

Co-authored with the Maldives Project Team Members. The Maldives Project includes the following research scientists: N.-A. Mörner (SE), J. Laborel (F), M. Tooley (GB), S. Dawson (GB), W. Allison (MV), S. Islam (BD), F. Laborel (F), J. Collina (F), C. Rufin (F), D. Dominey-Howes (GB), G. Possnert (SE) and T. Sjövold (SE).