Drowned reefs and antecedent karst topography, Au'au channel, S.E. Hawaiian Islands

Coral Reefs
By: , and 

Links

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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Drowned reefs and antecedent karst topography, Au'au channel, S.E. Hawaiian Islands
Series title Coral Reefs
DOI 10.1007/s00338-001-0203-8
Volume 21
Issue 1
Year Published 2002
Language English
Contributing office(s) Coastal and Marine Geology Program
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Coral Reefs
First page 73
Last page 82
Country United States
State Hawai'i
Other Geospatial Au'au Channel