Tyrendarra and Harman Valley lava flows and related features

The Tyrendarra and Harman Valley lava flows are two of the best preserved young volcanic structures in Australia and illustrate clearly the volcanic processes that were widespread over Eastern Australia during late Quaternary times (last 2 million years).

The sites of significance outlined here are either unique or representative features of the lava flows, e.g. stony ridges, collapse depressions, tumuli, or illustrate the effect of the lave on drainage systems, e.g. swamp and lake formation, lateral stream development. Because of the youthfulness of the two flows, the original characteristics have been little modified by weathering adn erosion and the entire volcanic systems of Mount Eccles and Mount Napier are of considerable interest to students of volcanicity. It is stressed that these entire systems are of National significance and a management strategy should be formulated to take account of these as entire systems and not just as isolated or separate components. Several of the sites selected in this report are some of the best examples of lava features in Australia (e.g. the Wallacedale tumuli and the constricted section of the Tyrendarra flow at, and south of, the Princes Highway). It is recommended that no major developments or disturbance be permitted on the Tyrendarra and Harman Valley flows in the Portland Shire.