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Science 27 May 1983:
Vol. 220. no. 4600, pp. 913 - 918
DOI: 10.1126/science.220.4600.913
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Articles

Insular Erosion, Isostasy, and Subsidence

H. W. Menard 1

1 Professor of geology in the Institute of Marine Resources and Scripps Institution of Oceanography, University of California, La Jolla 92093

Organic reefs and shore erosion record the intersection of sea level with islands. From this record it is possible to reconstruct the history of vertical movement of the islands and the adjacent deep sea floor, including midplate swells. As judged by coral thickness, islands with barrier reefs sink as though they were on thermally youthful crust regardless of the actual age. Reefless islands do not sink until truncated by erosion. Apparently, thermal subsidence is balanced by isostatic uplift in response to erosion. Barrier reefs prevent wave erosion of encircled volcanoes and capture products of stream erosion so that isostatic uplift is eliminated. Insular shelves widen initially at rates of 0.6 to 1.7 kilometers per million years; the rates decrease with time. Thus the subsidence of islands depends on the size of the is land and the presence of reefs, and it may not always be the same as that of the surrounding oceanic crust.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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P. D. Nunn and R. Pastorizo (2007)
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Critical Depth for the Survival of Coral Islands: Effects on the Hawaiian Archipelago.
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