Created from Chaos Coastal Trail
You may not realise at first as you make your way through the North-West Coast’s rolling fields or along its picturesque coastline that beneath the rich soil and weathered rocks lies some of Australia’s most unique and fascinating geological experiences. For one corner of a small state, the region boasts a rich and diverse range of geological features that are exceptionally well exposed for the casual observer. Here, the handiwork of the Earth’s massive forces and geomorphological processes are evident in almost every view. Rocks from all major geological periods are found and Tasmania is custodian to Australia’s key glaciated landscapes, of which Cradle Mountain is iconic.
In December 2004, a self-guided roadside geological trail called Created from Chaos was launched to highlight 13 of the North West Coast’s unique geological features. The concept was initiated by local geologist and photographer Peter Manchester and supported by the Rotary Club of Devonport South-East, state and local government, the Cradle Coast Authority, the business sector and other community organisations.
The trail is concentrated along 60 kilometres of scenic shoreline between Devonport’s Mersey Bluff and Wynyard’s Table Cape where you will encounter some of Tasmania’s oldest deformed rocks (750 million years) along a coast sculpted by recent ice-age effects and violent volcanic activity.
You can be guided along the trail via a full colour map pamphlet which can be found at visitor information centres in the region. Specially designed interpretative signage will then give you an insight into the history and formation of these unique geological sites. Directions allow you to travel the trail from east or west, or to visit sites individually. The trail is a fascinating and highly visual component in the shaping of Tasmania as we know it today. The various sites provide the foundations of the natural beauty, intriguing wildlife, history and heritage that the North-West Coast has to offer.
Mersey Bluff, Devonport
Mersey Bluff is composed of Jurassic dolerite (approximately 180 million years old). In places exposed surfaces display unusual markings that were once believed to have been carved by Aboriginal people. However these are now considered to be a result of weathering and root action.
Here a sequence of Eocene (37.5 million years old) basalt lava flows has been well exposed by coastal erosion. Columnar jointing is well displayed in both plan view and cross section, with varying joint patterns indicating multiple lava flows. A range of coastal landforms add interest. Best visited at low tide.
This site displays the contact between Proterozoic Ulverstone Metamorphics and relatively unmetamorphosed Proterozoic Oonah Formation rocks to the west. A particular feature is the stretched pebble conglomerate that indicates the forces these rocks were subject to during metamorphism and deformation. Best visited at low tide.
Three Sisters Reserve
This site offers views towards the Three Sister Islands which are composed of Early Cambrian chert. Early Cambrian basalt occurs on nearby Penguin Point. The chert and the associated basalt were deposited in an oceanic environment and were later thrust into the ancient Tasmanian crust during the Early Cambrian Delamerian Orogen.
Hall Point, Sulphur Creek
Well exposed and accessible angular unconformity between tightly folded Proterozoic metasedimentary rocks (Oonah Formation, approximately 700 million years old) and Early Ordovician sandstone and conglomerate (approximately 480 million years old) showing more open folds.
The point is a unique structural boundary between two major rocks of two different ages, that also exhibit two different weathering patterns. A past seashore of sandstones, mudstones with possible wormcasts and many variety of pebbles and cobbles indicating an active past marine environment. Best visited at low tide.
Sulphur Creek Boat Ramp
Pillow lavas and unusual folding exposed in shore platform. The pillow lavas are best record of submarine volcanic activity during deposition of Oonah Formation (approximately 700 million years old). Best visited at low tide. Burnie Basalt Columns, North Road and Marine Terrace Well exposed and accessible columnar jointed basalt. Columns approach ideal hexagonal symmetry and show curved 'ball and socket' joints across columns.
Parsonage Point, Burnie
A number of dolerite dykes intrude some Late Proterozoic sandstones of the Burnie Formation, and apparently were injected as molten magma into unconsolidated sands about 700 million years ago. The dykes have been critical to dating this sequence and the equivalent Oonah Formation. Location: behind Burnie Makers Centre.
This site hosts a number of geological features in a small area. Tertiary basalt with mantle xenoliths overlies Late Carboniferous sediments with angular unconformity. Late Carboniferous glacial sediments (tillites, varves etc.) overlie deformed Proterozoic metasediments with angular unconformity upon which striations occur. Best visited at low tide.
Seabrook Pines Point
These rocks formed on the bed of a shallow sea about 300 million years ago. At the nearby coast a glacier calved icebergs. As the icebergs melted rocks of various types that had been carried by the glacier rained down upon the muddy sea floor, and are now preserved as dropstones.
Wynyard Fossil Bluff, Wynyard
Here the Miocene (23 - 5.3 million years old) sediments forming the cliff unconformably overlie Late Carboniferous glacial sediments that are about 300 million years old and make up the shore platform. The Miocene rocks contain a rich shallow-marine fossil fauna. Please note that collecting is not permitted in the Conservation Area.
Table Cape, Wynyard
This striking landform is composed of basalt lava likely to formed as crater-filling lava lake. The lava would have been ponded by granular material forming the slopes of the volcano but which has now largely eroded away. Related flows on the landward side have been dated at 13.3 million years (Miocene).
About Table Cape
Mary Ann Cove
Rocky Cape - Burgess and Mary Ann Cove
Most of the rocks exposed around Rocky Cape are formed from sandstones deposited between 750 and 1000 million years ago. These were folded and metamorphosed to quartzite around 510 million years ago.
Interbedded siltstone and mudstone deposited between 750 and 1000 million years ago and folded around 510 million years ago. In places these have been intruded by dolerite dykes that might be about 700 million years old. Good shore platform exposure of rocks that underlie much of northwest Tasmania.
Brickmakers Beach, Cowrie Point
Geological Discription Fretwork and honey comb weathering. Phyllite and slate sequences in tilted rocks. Cambrian age. Highly sculptured with evidence of iron and minerals. Interbedded siltstone and mudstone deposited between 750 and 1000 million years ago and folded around 510 million years ago. In places these have been intruded by dolerite dykes that might be about 700 million years old. Good shore platform exposure of rocks that underlie much of northwest Tasmania
This is an unconformity, i.e. a geological contact at which underlying and overlying layered sedimentary rocks of different ages meet at an angle (here about 22 degrees). The older, lower siltstone formation, about 1200 million years old, has evidently been uplifted, slightly tilted, planed off by erosion, and overlain by the younger formation, of conglomerate and quartzite, about 750 million years old. This unconformity can be mapped out or followed over a large area, but this spot offers the most accessible exposure. Best visited at low tide.
The Nut, Stanley
This is a Monolithic remnant of a volcanic plug of Igneous rock from the Tertiary Age. This spectacular landform is composed of basalt lava likely to formed as crater-filling lava lake. The lava would have been ponded by granular material forming the slopes of the volcano but which has now largely eroded away. The basalt is 12.5 million years old (Miocene).
The structures of several basalt flows that erupted under water are very well displayed on the coast around Highfield Point. Features include wrinkled pillows, lava lobes, mega pillows with radial columns and sheet lavas with vertical columns. Eruption occurred in the Miocene Epoch (23 - 5.3 million years ago).
Lookout over Duck Bay, Smithton
From the Lookout it is possible to see coastal features that have developed since the sea level rose after the last ice age about the 6000 years ago.
Stony Point, Robbins Passage
Onion and honeycomb weathering on rocks by the boat ramp. A coastal section though a Middle to Late Cambrian (500 - 495 million years old) turbidite fan complex. These rocks were deposited as density flows down the continental slope.
The rocks exposed here form part of the Upper Rocky Cape Group, a group of rock units deposited during rifting of the Nuna supercontinent (around 1.45 to 1.3 billion years ago). Similar rock units have been observed in North America. This 1085 million year old Quartzite shows well preserved ripple features developed on bedding surfaces. Other notable sedimentary features include cross-stratification and a network of possible syneresis cracks. Note: access is by tour only. Call the Stanley Visitor Information Centre for more information
Cape Grim & Doughboys
Cape Grim and the Doughboys were the site of intraplate basaltic volcanism about 24 million years ago. Exceptionally well preserved examples of submarine pillow lavas, sills, lobate lavas, volcanic breccia and tuff are exposed in rock platforms and steep coastal cliffs. Please note there is no private access to this site. Please contact the Stanley Visitor Information Centre for tour options.
Green Point, Marrawah
Clusters of well developed circular solution pans up to 2 m in diameter have formed on the shore platform of Tertiary limestone.
Arthur River Gardiner Point, "Edge of the World Lookout"
The Proterozoic rocks exposed along this coast display complex sedimentary features including graded bedding, scour and fill structures, pseudonodules, clastic dykes, load cast structures, well-developed wave ripple marks and ripple casts.
Excellent exposures of Tasmania's oldest rocks; the Pedder River Siltstone, a rock unit with microbial mat features which forms the base of the Rocky Cape Group. These 1.4 billion year old sedimentary rocks are intruded by a large white quartz vein, running out to sea. The vein has some associated copper mineralisation, tested by a small, filled shaft.