Geology and Geomorphology
The Tarkine Wilderness has been described as representing a microcosm of Tasmanian geology and geomorphology and its dominant features include:

• The Rocky Cape Region of the north-west which is largely Precambrian unmetamorphosed rocks.
• The Arthur Lineament which is a linear belt of Precambrian metamorphics cutting through the Tarkine along a north-east/south-west axis.
• The Dundas Trough in the south-west which is an area of late Precambrian to Devonian sequences.
• A linear belt of Devonian-Carboniferous granites along the coast south of Sandy Cape, as well as east of the lower end of the Arthur Lineament.
• Some tertiary basalts in the north-east.

The Tarkine Wilderness hosts outstanding examples of magnesite karst geomorphology. This is expressed within the Arthur Lineament as small undecorated caves, sub-surface cavities, sinkholes, springs, and surface features including gorges and pinnacle type formations.

Another exceptional example of the local geomorphology is the Huskisson Syncline - a fold structure "composed of Siluro-Devonian clastic sedimentary rocks underlain by Ordovician limestones and Cambrian ultramifics" (Sharples 1992a). It features two concentric ridges formed on resistant Siluro-Devonian quartz sandstones. A section of the syncline has been offset by a fault which also controls the course of the Alfred River.

The Rapid River is a particularly well-expressed example of a fluvial system influenced by geological lineament. According to Sharples (1992a) "[T]he river channel diverts along fold trends for short distances" but follows a generally linear course, "cutting directly across regional fold trends for some twenty kilometres". It is recognised as the largest example of a fault-controlled river channel in north-west Tasmania.

In summary, the Tarkine region is an area of international significance. Its ecological, cultural and financial values combine to powerfully justify its long term protection as a National Park- World heritage area. Whilst the Tarkine remains divided in its current form, (being several different reserves and only 5% of it as National Park), it remains susceptible and open to continued resource extraction which further devalues the above mentioned attributes.

By joining us for walk in the Tarkine, you not only enjoy its natural brilliance, you also make a positive contribution to its full protection for generations to come.