Sb11 Jacksons Creek, Sunbury - Valley Forms

This information has been developed from the publications:

Sites of Geological and Geomorphological Significance in the Western Region of Melbourne (1986) by Neville Rosengren
Sites of Geological and Geomorphological Significance on the Coast of Port Phillip Bay (1988) by Neville Rosengren.
Sites of Geological and Geomorphological Significance in the Shire of Otway (1984) by Neville Rosengren.

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 (external link) for details of geological heritage reports, and a bibliography.

Location	Sunbury - 007370. Shire of Bulla. Valley of Jacksons Creek 2 km east of Sunbury town centre.	Sb11 - Strongly jointed lava flows forming rapids in Jacksons Creek, Sunbury.
Access	Sunbury road
Ownership	Private land
Site Description	The significant features of the site are the broad incised meander of Jacksons Creek, the inliers of Newer Volcanics basalt enclosed by an old meander loop of the creek, alluvial terraces, a hanging valley that is cutting into the basalt on the northern side of the valley, and extensive outcrops of Newer Volcanics in the valley to the south near the Sunbury Wastewater Treatment Plant.
	These outcrops are outstanding examples of features of the Newer Volcanics. They form rapids and small falls in Jacksons Creek and further downstream there are columnar basalts and tessellated pavements. The stone ruins adjacent to the falls is probably a mill that was water powered from the falls.
	The 30 m cliffs at grid reference 008364 show a section of several lava flows including massive columnar jointing in the flows at river level, deeply weathered flows overlying these, sediments contained between flows, and closely jointed and blocky basalt in the upper sectors of the cliff.
Significance	Regional. The site displays the features produced by valley widening as Jacksons Creek incises in the basalt plain around Sunbury. The lava flows exposed in river cliffs in the southern part of the site are some of the most complex that occur along valleys in the study area.
Management	Class 1. Continuation of the present rural land use will maintain the features of significance. Residential subdivision, road construction or quarrying would obscure the significant features of the site. As it is close to and accessible from Sunbury, the site could be incorporated into a public open space system if the land was no longer required for rural purposes. This applies particularly to the basalt features described.

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