Merri Creek Management Committee

Site location mapLOCATION: YARRA 5000/05.07 E24510 N15470

Left bank of Merri Creek near Fairfield Hospital 100 m west of Yarra Bend Park Road.

ACCESS: The site is difficult to access from the left bank due to the steep bank and the loose surface. It is best viewed from the right bank of the creek form the Merri Path opposite Walker Street.

OWNERSHIP & MUNICIPALITY: Public Land, City of Northcote.

SITE DESCRIPTION. The basalt on the eastern side of the Merri Creek shows a complex fracture system in the basalt lava flows. At the base of the cliff are widely spaced vertical fractures cut by closely spaced horizontal joints. Higher in the cliff the vertical fractures are inclined and diverging and form a crude radial pattern. The persistence of sub-horizontal joints disrupts the continuity of the radial fractures and gives an irregular appearance to the cliff face. A talus of broken and weathered basalt blocks lies at the cliff base. The jointing is a result of cooling of the lava with the vertical fractures forming roughly at right angles to the upper and lower surfaces of the lava flow. It is possible there is more than one flow unit at this site.

SIGNIFICANCE RATING: REGIONAL

This is a good example of a radial fracture pattern in basalt lava flows and illustrates the complexity of jointing that occurs in basalt. It complements other sites that illustrate different fracture systems in the basalt exposed in the Merri Creek gorge downstream of Rushall Station.

SITE SENSITIVITY, THREATS, POTENTIAL UTILISATION

CLASS 3. This is a robust site and the natural rate of weathering and site deterioration is low. It should be kept visible from the western (right bank) side of the creek by cutting back willows and shrubby weeds that obscure the visibility of the site. It is a potentially hazardous site due to a number of loose blocks on the cliff face and the inherent instability of the steep fractured rock of the face. It may be safely and gainfully viewed from the right bank and this vantage point should be retained.

REFERENCES: None known.

Radial basalt columns at Merri Creek in Yarra Bend Park

 

 

 

Photograph 3. Radial basalt columns at Site 3.