Mega-tsunami deposits or evidence of uplift within the Hawaiian Islands
Abstract
For several years there has been a controversy over the origin of coral-bearing deposits on the island of Lanai (Hawaii). Studies underway have expanded the study of marine deposits from Lanai to adjacent islands. Coral-bearing deposits are present at elevations up to 190 m on Lanai, 90 m on Maui, 90 m on Molokai, 30 m Oahu, 30 m on Niihau, roughly 75 m on Kauai (as well as a few m above sea level on the Kohala Volcano on the island of Hawaii). The deposits show a persistent pattern of increased weathering, color change, increasing age and increase in the number of fossils now extinct in Hawaiian waters, with elevation above modern sea level. Changes in slope are also observed reflecting changing relative sea level. A review of radiometric ages suggests in-situ corals as well as marine conglomerates were deposited near sea level and were contemporaneous. The distribution, stratigraphy and age of marine sediments around the islands are consistent with a history of uplift combined with changing sea level. We document the age, rock and fossil characteristics and distribution of sub-aerially exposed marine sediments, in the Hawaiian Island chain. We suggest that the Hawaiian Islands have experienced lithospheric adjustments during the last 500,000 years that have left marine deposits exposed above sea level.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.H41C0311K
- Keywords:
-
- 9355 Pacific Ocean;
- 8121 Dynamics;
- convection currents and mantle plumes;
- 4568 Turbulence;
- diffusion;
- and mixing processes;
- 3000 MARINE GEOLOGY AND GEOPHYSICS;
- 3020 Littoral processes