| Abstract: | During the last glacial maximum (LGM), about 21,000 years ago, the Hawaiian Islands of Maui, Lanai, and Molokai were interconnected by limestone bridges, creating a super-island known as Maui-Nui. Approximately 120 m of sea-level rise during the Holocene Transgression flooded, and then drowned, these bridges separating the islands by inter-island channels. A new multibeam high-resolution bathymetric survey of the channels between the islands, coupled with observations and video-transects utilizing DeepWorker-2000 submersibles, has revealed the existence of numerous drowned reef features including concentric solution basins, solution ridges (rims), sand and sediment plains, and conical-shaped reef pinnacles. The concentric basins contain flat lagoon-like bottoms that are rimmed by steep-sided limestone walls. Undercut notches rim the basins at several depths, marking either sea-level still stands or paleo-lake levels. All of the solution basins shallower than 120 m were subaerial at the LGM, and at one stage or another may have been shallow shoreline lakes. Today, about 70 drowned reef pinnacles are scattered across the Maui-Lanai underwater bridge and all are situated in wave-sheltered positions. Most drowned during the interval between 14,000 and 10,000 years ago when sea-level rise averaged 15 mm/year. Virtually all of the surficial topography in the Au‘au Channel today is a product of karst processes accentuated by marginal reef growth during the Holocene. Both the submerged basins and the drowned reefs represent an archive of sea-level and climate history in Hawaii during the late Quaternary. |
| Genre: | Article |
| ProdID: | 70023950 |
| Citation Author: | Grigg, R. W.; Grossman, E. E.; Earle, S. A.; Gittings, S. R.; Lott, D.; McDonough, J. |
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| Citation End Page: | 82 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Coral Reefs |
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| Citation Number Of Pages: | 10 |
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| Citation Search Results Text: | Drowned reefs and antecedent karst topography, Au‘au channel, S.E. Hawaiian Islands; 2002; Article; Journal; Coral Reefs; Grigg, R. W.; Grossman, E. E.; Earle, S. A.; Gittings, S. R.; Lott, D.; McDonough, J. |
| Citation Start Page: | 73 |
| Citation Volume: | 21 |
| Citation Year: | 2002 |
| Type: | citation/reference |
| Text: | Drowned reefs and antecedent karst topography, Au‘au channel, S.E. Hawaiian Islands; 2002; Article; Journal; Coral Reefs; Grigg, R. W.; Grossman, E. E.; Earle, S. A.; Gittings, S. R.; Lott, D.; McDonough, J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 2002 00:00 -0600 |
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