Shore platform development around Lord Howe Island, southwest Pacific

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Show simple item record Dickson, Mark en 2012-03-05T21:24:22Z en 2006 en
dc.identifier.citation Geomorphology 76(3-4):295-315 2006 en
dc.identifier.issn 0169-555X en
dc.identifier.uri en
dc.description.abstract This paper describes the morphology of near-horizontal basalt and calcarenite shore platforms around Lord Howe Island as well as the lithological and process environment in which they occur. The morphology of platforms around the island is highly varied. For instance, they occur at a wide range of elevations between low-tide level and several metres above the highest tides, and their width ranges between just a few metres to over 100 m. However, common to most platforms is that they have near-horizontal surfaces that terminate abruptly in a steep scarp at their seaward edge. Correlations indicate that the variability in platform elevation and width is attributable to variability in key parameters of erosion, such as rock resistance and shoreline water depth. Whereas wider platforms occur in rocks of lesser resistance, platform elevation is shown to increase both as rock resistance and the depth of water at the shoreline increases. Wave exposure has a significant control on platform width in some instances, but an over-arching relationship was not detected. Most platforms around the island appear to have developed over the Holocene and a conceptual model is proposed to account for the varied morphology of platforms that have developed over this period. Resistant plunging cliffs occur along about 18% of the rocky coastline of Lord Howe Island and represent the starting point for the model. Where cliffs have yielded to wave erosion platforms have been initiated at an elevation controlled predominantly by rock resistance and shoreline water depth. At Lord Howe Island narrow platforms up to about 20 m wide in exposed locations generally occur about 4 to 6 m above high tide level, and have apparently been subject to very infrequent erosion. Shore platforms about 20 to 40 m wide have generally formed in less resistant rocks, are somewhat lower at about 2 to 3 m above high tide level, and have been subject to more frequent erosion over the Holocene. Most basalt platforms around the island fall within these first two categories, but there are some instances of platforms about 50 m wide. These platforms have formed in rocks of comparatively low resistance and are relatively low in elevation occurring close to the level of high tide. An interesting feature of some of these wide platforms is that, unlike the morphology of narrower platforms, raised ramparts sometimes occur on their outer edge. en
dc.publisher Elsevier en
dc.relation.ispartofseries Geomorphology en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obatined from en
dc.rights.uri en
dc.title Shore platform development around Lord Howe Island, southwest Pacific en
dc.type Journal Article en
dc.identifier.doi 10.1016/j.geomorph.2005.11.009 en
pubs.issue 3-4 en
pubs.begin-page 295 en
pubs.volume 76 en
dc.rights.holder Copyright: Elsevier en
pubs.end-page 315 en
dc.rights.accessrights en
pubs.subtype Article en
pubs.elements-id 88465 en Science en School of Environment en
pubs.record-created-at-source-date 2010-09-01 en

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