8522-8 Grap Creek

This information has been developed from the publications:

Sites of Geological and Geomorphological Significance in Central Gippsland (1981) by Neville Rosengren, M.S McRae-Williams and S.M Kraemers.
Sites of Geological and Geomorphological Significance in the Gippsland Lakes Catchment (1984) by Neville Rosengren.
Sites of Geological and Geomorphological Significance in East Gippsland, Victoria (1981) by Neville Rosengren, M.S McRae-Williams

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 values. Reference should be made to the most recent reports. See the Earth Science Heritage section of the Geological Society of Australia website for details of geological heritage reports, and a bibliography.

Location:	987308. 8 kilometres north of Nowa Nowa.	Sites 8522 8 9
Abstract:	Abstract of graptolite-bearing Ordovician sediments. Magnetic deposit.
Access:	Old Nowa Nowa - Buchan Road.
Ownership:	Crown land.
Geology:	Graptolites have been recorded from several localities in Gap Creek where Ordovician sandstones, slates and black shales are exposed. The graptolites occur as compressed whitish impression in the black shales and consequently are not easily identified. However, several species of Climacograptus, Diplograptus and Dicellograptus have been identified and this association is typical of the zone of Dicranograptus clingani of the Eastonian subdivision of the Upper Ordovician. The Ordovician sediments at Gap Creek are overlain by rhyodacite of the Snowy River Volcanics. These are heavily charged with pyrite and micaceous hematite, the latter of which is derived from the redistribution of iron oxide from the associated magnetite bodies during intense shearing movements. In the Gap Creek area sporadic outcrops of hematite occur and drilling of these deposits has shown that they pass rapidly into magnetite with depth.
Significance:	Regional. Graptolite fossil localities are rare in Eastern Victoria. The magnetite deposit at this locality is the largest known in Eastern Victoria.
Management:	Access to the graptolite fossil sites in Gap Creek should be maintained and may need to be formalized with any future mining operators.
References:	Cochrane, G.W. and Samson, H.R. 1947. 'Geology of the Nowa Nowa - South Buchan area', Proc. Roy. Soc. Vict., 60 :93-125. Bell, G. 1959. 'The iron ore deposits of Nowa Nowa, East Gippsland', Bull. geol. Surv. Vict. 57.

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