5-12 Tyrendarra lava flow at Quamby Park

This information has been developed from the publications:

An assessment of the Geological/Geomorphological Significance of Private Land in the Shire of Portland (1981) by N. Rosengren, J Mallen, T Shepherd.

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.

Locality:	7221-695658. Quamby Park.
Access:	Tyrendarra School Road off Princes Highway.
Geology/Geomorphology:	Two erosional gaps in a high Pleistocene calcareous dune ridge of Quamby Park are former outlets of the Fitzroy River. The Tyrendarra flow was constricted at these points but ultimately negotiated the erosional gaps and extended a further 16 kilometres to the south. Complex flow lines developed on the basalt surface upstream from the gaps, but to the south the lava is now buried beneath alluvium and Holocene dune ridges. The mouth of the Fitzroy River is now located approximately five kilometres east of Quamby Park.
Significance:	State. The site illustrates the interactions between volcanic, coastal and fluvial processes, and is an important site for the Quaternary stratigraphy of the Portland district.
Management:	To retain the scientific interest of the site, it is essential that the Pleistocene ridges and the formers, now lava-filled outlets of the Fitzroy River are not extremely disturbed e.g. quarrying and further wetland reclamation. This particularly applies to the former valley margins of the Fitzroy River.

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