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Lady Julia Percy Island

This information has been obtained from the report: Eruption Points of the Newer Volcanic Province of Victoria by Neville Rosengren. This report was published in 1994 and was prepared for the National Trust of Australia (Victoria) and the Geological Society of Australia (Victorian Division). The review of eruption points was based on an earlier unpublished manuscript Catalogue of the post-Miocene volcanoes of Victoria compiled by O P Singleton and E B Joyce (Geology Department, University of Melbourne 1970).

Geological heritage sites, including sites of geomorphological interest and volcanic heritage sites, are under regular revision by the Geological Society of Australia, especially in the assessment of significance and value. Reference should be made to the most recent reports. See the Earth Science Heritage (external link) section of the Geological Society of Australia website for details of geological heritage reports, and a bibliography.

38 25 30S 142 00 00E (external link); 7321-3-3 (Lady Julia) 867471. 20 km of Port Fairy (8 km offshore). One difficult landing site. Access restricted by Department of Conservation and Natural Resources.

No Local Government area.

Crown land.

State Wildlife Reserve. Abundant coastal outcrop.

Type 2:

Lava shield.

Lady Julia Percy Island is a low, flat island 2 km long and 1 km wide at the south-western end tapering towards the north-east. The plateau surface averages 30 m to 40 m above sea level and is bounded by cliffs on all sides. Shore platforms and reefs prevent boat landings apart from a sheltered cove on the northern side. The island is built of submarine pillow lavas and hyaloclastite deposits, overlain by several sub-aerial basalt flows. The sequence is well displayed in extensive coastal exposures. Radiometric dates of 6.2 and 7.8 million years have recently been obtained from a sample from the island (J Edwards in prep).

40+ m.

National:

This is the only major basalt island off the Western Victorian coast. Although not readily accessible, the volcanic sequence is unusual and clearly exposed. Basaltic rocks of this age are restricted in Victoria. Moreover the Late Miocene age is unexpected given the much younger Quaternary dates from nearby basalts on the mainland. The origin of the island is of major geological interest.

Class 3:

Given the isolation, difficulty of landing and land tenure, there are no threats to the geological and geomorphological values of the island.

References:

McCoy Society 1936. Lady Julia Percy Island: reports of the expedition of the McCoy Society for field investigation and research. Proceedings of the Royal Society of Victoria 49, pp. 327-427.

Coulson, A. 1941. The volcanoes of the Portland district. Proceedings of the Royal Society of Victoria 53, pp. 394-402.
Ollier, C.D. & Joyce, E.B. 1964. Volcanic physiography of the Western Plains of Victoria. Proceedings of the Royal Society of Victoria 77, pp. 357-376.
Gill, E.D. & West, A.L. 1971. The Aborigines and Lady Julia Percy Island, Victoria. Victorian Naturalist 88, pp. 84-88.
Edwards, J. in prep. The geology, petrology and geochemistry of Lady Julia Percy Island, south-western Victoria. MSc thesis. University of Melbourne (unpubl).
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