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Discover the stories written in the landscape across Flinders Island and its surrounding Bass Strait archipelago along the Furneaux Geotrail.

The diverse and picturesque landscape of the Furneaux Group includes unspoilt beaches, rugged rocky coasts, impressive mountains, remote islands, bush tracks and trails, rich agricultural land, lagoons, wetlands, conservation areas and national parks.

It also possesses spectacular and significant geological features, which developed over the last 420 million years.

The Furneaux GeoTrail consists of 26 geosites which provide an opportunity to learn about the geology and important geological events that have shaped the current landscape. It also takes you to the most beautiful locations on Flinders Island. Some of the geosites are marked with Interpretation signage, others are ‘virtual’ geosites.

This GeoTrail webapp allows you to visit all of the geosites on your smartphone, ipad or computer. It contains additional information and photos about each of the geosites.

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1. North East River

View the local coastal landscape shaped by sea and wind.

2. Palana

Look to the north across the water and imagine a time when the ice age land bridge extended across to Victoria. Use the app to learn about the sand dunes behind the beach.

3. The Dock

Follow the indistinct track, southwest from the lower carpark, along the scenic rocky shoreline beneath the impressive sculptured cliff of Mt Killiecrankie.

4. Stackys Bight

A spectacular arch developed in calcarenite. Stackys Bight can be accessed via the coastal walk from the Killiecrankie Geosite (3 hs return, 8 km).

5. Killiecrankie

This Geosite features the local granite and source of the Killiecrankie diamonds [topaz].

6. West End

Walk along the beautiful West End Beach or explore the granite coastline near the boat ramp. The more adventurous should visit the nearby spectacular Egg Beach (4 km return along rocky coast to northwest, 1-2 hr).

7. Castle Rock

A spectacular tor developed on 400 million year old granodiorite. One of the iconic landforms on Flinders Island.

8. Furneaux Museum

... houses a collection of the common rocks and fossils found along the GeoTrail. Check the Furneaux Museum website or the recorded message on 6359 8434 for opening times.

9. Allports Beach

Toilet and picnic facilities make this the perfect spot for lunch. Explore the beach or take one of Tasmania’s 60 Great Short Walks to visit Castle Rock.

10. Settlement Point

The old wharf at Settlement Point provides excellent views of Marshall Bay and Cave Beach.

11. Sawyers Bay

Classic Flinders Island granite coastal scenery with striking views south across the sheltered waters of Arthurs Bay and beyond.

12. Blue Rocks

Scenic slabs of exfoliating granodiorite can be accessed via Long Point Beach (best at low tide) or via a short unmarked track off the Palana Road approximately 10 kilometres north of Whitemark.

13. Long Point

Outcrops of Mathinna Beds can be reached via a short walk along Long Point Beach (best at low tide).

14. The Bluff

Walk from the Whitemark Wharf, or drive to the end of Bluff Road. Great views and a unique sand spit. Go past the rocky headland (Mathinna Beds), to see the delta forming at the mouth of Pats River.

15. Whitemark

An interpretation sign outlines all the geological sites you can visit – travelling through millions of years, seeing the forces that have shaped the landscape.

16. Strzelecki Peaks

One of Tasmania’s 60 Great Walks highlighting the importance of the 380-400 million year old Devonian granite to the region.

17. Fotheringate Bay

Fotheringate Bay offers a great view of nearby Strzelecki Peaks. Karst features have developed in the calcarenite at the west end of the beach.

18. Trousers Point

Another of Tasmania’s 60 Great Walks, includes local granite outcrops, interesting limestone features and scenic views. This track provides an easy link with the Fotheringate Bay Geosite.

19. Badger Corner

The Mathinna Beds, some of the oldest rocks on the island, are best seen here at low tide.

20.Petrifaction Bay

Basalt boulders and lava features tell an intriguing part of the island’s geohistory.

21.Yellow Beaches

Walk along the beach to see sedimentary rock layers that were deposited between 10,000 and 100,000 years ago and local granite outcrops.

22. Vinegar Hill

A wonderful vantage point looking out over Franklin Sound to the islands.

23. Cameron Inlet

Walk out onto the beach to look for giant megalodon shark teeth.

24. Patriarch Inlet

Explore the beach or visit Red Bluff (2-3 hr return, 7km).

25. Furneaux Lookout

Both this and Walkers lookouts provide panoramic views over much of Flinders Island.

26. Walkers Lookout

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These are some of the common rocks you can find on your journey along the Furneaux Geotrail.

badger corner rock

MATHINNA BEDS: The oldest rocks in the Furneaux Group are the Mathinna Beds comprised of slates and quartzite. These rocks were originally laid down as sediments in the deep ocean around 420 million years ago.

grantitic rock

GRANITES: The intrusion of granite magmas around the Mathinna Beds some 380 million years ago led to granitic rocks being the most commonly seen feature of the Furneaux Group today.

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GRANITES: The variety of mineral mixes present in a given outcrop varies widely. This accounts for the many different colours and textures of the granitic rocks we see today.

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PEGMATITE: The granites also contain patches of very large crustals called pegmatites. These are common in the Killiecrankie area where some may containthe gem mineral topaz.

dolerite

DOLERITE: At some point between the between 380 – 60 million years ago, dolerite intruded into the both the Mathinna Beds and granites of the Furneaux Group.

basalt

BASALT: We don't appreciate how much basalt there is on Flinders Island today as most of it is covered by more recent sand sediments. Outcrops at Petrifaction Bay offer a rare chance to see them first hand.

limestone

LIMESTONE: Of much more recent origin are the limestones on Flinders Island. They have formed from windblown calacerous sands comprised of the shells of marine forams that lived offshore in shallow waters to the west of Flinders Island.

calcareous sedimetns

CALCAREOUS SEDIMENTS: We can see the process of limestone formation in train today in the relatively young (perhaps 2 million years) calcareous rocks outcropping beside the road to Camerons Inlet.

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SANDSTONES: Recent deposits of sediments have consolidated into sandstone. Outcrops at Yellow Beach provide a key chance to see this process in action.

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BEACH SAND: We can easily see the geological processes of sedimentary rock formation underway around us today when walking along a beach in the Furneaux Group.

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The landscapes we see around us across the Furneaux Group of islands today are built upon layers of rock dating back over
400 million years up to recent times.

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Around 420 million years ago Australia was part of the Gondwana supercontinent which was then drifting southwards. Tasmania was located along the 30˚S latitude which puts it around about where Coffs Harbour is today.

At this time sediment from eroding mountains was carried out to sea to the edge of the continental shelf. Here the sands and silts slid down off the shelf to build up on the deep ocean floor at depths exceeding 1000m. This was the origin of the island's present-day Mathinna Beds.

The build up of sediments in the Mathinna Beds ended in the Devonian period around 400mya. Deformation along the trailing north eastern continental edge of Gondwana resulted in widespread folding and uplift of rocks. This mountain building event is called the Tabberabberan Orogeny. It lasted for tens of millions of years and affected much of the Australian east coast.

Having been uplifted and folded, the Mathinna Beds were then locally baked into hard metamorphic rocks as a series of granite magmas intruded in and around them between 400 and 380 mya.

These gave birth to the Furneaux Group's most distinctive rocks. Granite outcrops occur extensively across the islands today and were noted in Bass and Flinders 1798 voyage of discovery.

Then followed a long period of uplift and erosion on FLinders Island while glaciomarine and nonmarine sequences were deposited over much of the Tasmanian landmass.

The breakup of Gondwana started around 180mya when Africa and South America broke off the supercontinent. This event coincided with a new array of volcanic activity across Tasmania which saw huge dolerite dykes intrude into existing ancient rock layers. These are mostly seen in the Furneaux Group today in the precinct around Cape Barren and southern Flinders Island.

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In the leadup to the final breakup of Gondwana when Australia and Antarctica separated over the period 80-45mya, the Flinders Island block was uplifted by vertical faulting. Widespread erosion followed.

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At some point between 40–20mya while Australia tracked northwards away from Antarctica, volcanoes erupted around the Furneaux Group. These sent lava flows tracking across the landscape to fill in the eroded valleys that had formed in the time since the Flinders Island block was raised up clear of the surrounding ocean waters.

The most significant event for Furneaux Group geology in the last 10mya was the start of the last ice age around 2.5mya.

While ice formed up in glaciers and sea ice across the world, sea levels fluctuated wildly from between 20m-130m below current levels. This had the effect of not only opening and closing a land bridge between Tasmania and the mainland but also of creating a shallow embayment to the east of Flinders Island.

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As sea levels rose and fell, sands from the newly exposed marine areas blew up over the island covering up the basalt. Sands from the bay to the west were rich in marine shelled animals called forams. The 'Roaring 40s' winds piled these shells up to create a type of limestone / calcareous sand. To the east the ocean sands tended to accumulate more gently into compacted beds of quartz grains and marine fossils.

petrifaction bay photo

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In March 1773, the H.M.S. Adventure under the command of Tobias Furneaux recorded the position of a series of islands in the waters between Cape Howe on the New Holland mainland and Van Dieman's Land to the south.

Having become separated from Capt Cook aboard the H.M.S. Resolution as they journeyed up from the southern ocean, Furneaux charted the east coast of Van Dieman's Land prior to breaking off eastwards to rejoin Cook in New Zealand.

Today Furneaux's charting of the group of islands that bear his name marks the start of 250 years of scientific exploration and discovery across the Furneaux Group.

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Our knowledge of the Furneaux Group's geology has been built up steadily over the past 250 years thanks to the work of scientists and map makers.

A key highlight in this was the work Commander Stokes undertook on the HMS Beagle c.1841 to make a detailed chart of the islands of Bass Strait. Accompanying him on this work around the Furneaux Group was the famous Polish scientist Count Strzelecki.

Strzelecki's initial geological observations were expanded on from the 1870s onwards with several landmark reports and geological maps being produced in the 1940s.

Today the detailed geological map of the Furneaux Group provides a snapshot embracing generations of ongoing scientific research into the islands' geological heritage.

Read detailed accounts from the 250 years of research and discovery across the Furneaux Group of islands ...

geological map

view from ocean

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strzelecki legacy

Paweł Edmund de Strzelecki was a Polish explorer and scientist whose travels left an indelible mark on the history of both Tasmanian geology and Flinders Island.

In 1845 his geological map of New South Wales, Victoria and Tasmania was published along with an account of the physical descriptions of these places. In his book, Strzelecki noted that ...

"On the 13th January, 1842, I ascended, from the westward, the highest peak of Flinders Island, which Captain Stokes, of H.M. surveying ship the "Beagle" has done me the honour of naming Strzelecki's Peak (2550 feet)."

Strzelecki images

view to Strzelecki Peak

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The Furneaux Geotrail is an initiative of the Flinders Island community proudly supported by the Tasmanian Government.

To discover the full range of things to do on this remarkable Bass Strait island go to the visitflindersisland.com.au website.

site design: Nature Tourism Services