Lord Howe Island
August 07, 2003
Lord Howe Island is located in the Tasman Sea about 500 km off the east coast of Australia. This photo shows parts of the central section of the island. In the scene above, looking southeast from Mt Eliza, two beach types can be seen. At the lower left, a small basaltic cobble and boulder beach has formed in a narrow bay called Old Gulch. About 300 m to the south (i.e. to the right in the photo), North Beach consists of much whiter, mostly medium grained sand composed entirely of calcium carbonate. The parent materials for this beach are mainly coral and shell fragments, transported by wind and wave action from the adjacent lagoon. Wave action in Old Gulch is stronger than the lagoon at North Beach -- the waters there are protected by a fringing reef. Siliceous beaches, common around the world, are absent on Lord Howe Island. The core of the island is basalt, a low silica igneous rock.