Our Latest News

Improved access to a World Heritage view

24/07/2017

An upgrade of the popular viewing platform on the shore of Lake St Clair has now been completed, improving disability access to one of the finest viewing points of the Tasmanian Wilderness World Heritage Area.More

Improved access to two of the North-west's natural wonders

24/07/2017

The North-west is home to some of Tasmania's most stunning natural attractions, and we are pleased to announce upgrades have now been completed at Trowutta Arch and Dip Falls.More

Overland Track bookings open with a rush

18/07/2017

Tasmania's iconic world-renowned bushwalks are a key driver behind the boom in visitor numbers to the state, and bookings for the Overland Track walking season have opened with a rush for the peak summer period.More

Geoheritage

Geological Timeline

Tasmania along the Geological Timeline

Tasmania’s spectacular geodiversity has contributed directly to the islands' biodiversity. The State's geodiversity is a result of continental drift, ice ages, humid, hot conditions and earthquakes occurring over more than a billion years.

A very brief and summarised account of Tasmania’s geological history is outlined below. Although Tasmania is referred to frequently, it was not until about 45 million years ago that Tasmania began to look anything like it does today.

Precambrian Eon

4600 - 635 mya

 

The Earth formed about 4600 million years ago.

Little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history. This is because traces of the geological heritage of Precambrian times have been erased by relentless subsequent erosion.

First evidence of simple life forms, cyanobacteria, the building blocks for stromatolites, are among the oldest form of life on Earth, dating back 3.5 billion years. Their ability to extract hydrogen from water through the process of photosynthesis led to oxygen being released which, over long ages, led to an increase in the atmospheric concentration of oxygen, and paved the way for explosion of aerobic life which was ultimately to follow.

Sequences of rock known as dolomite (aged at around 800 million years) contain Tasmania’s oldest stromalolite fossils.

The oldest rocks in Tasmania are found in the west. These were laid down as sediments in a shallow sea and subsequently folded and transformed into quartzites and schists. Examples of these ancient metamorphic rocks can be seen in the Arthur and Frankland Ranges and Frenchmans Cap.

Ediacaran
Period

635 - 542 mya

 

First complex multicelled life forms appear roughly 600 mya. Life confined to the oceans.

What is now Tasmania was largely covered by shallow seas

Cambrian Period

490 - 443 mya

 

Global explosion of life in the seas. Tasmania has some fossils from this time, including trilobites.

Chains of volcanoes form across Tasmania, including Mt Read Volcanic Belt, a highly significant mineralised belt.

Ordovician Period

443 - 408 mya

 

 

Extensive erosion and subsequent deposition form the sandstones and conglomerates of West Coast Range and Denison Range.

Tasmania partly covered by a warm tropical sea and part of a much larger land mass of Gondwana situated near the equator. Gordon Limestone formed from the debris of marine life. Today this limestone outcrops in parts of the Franklin and Gordon River valleys and around Mole Creek, where subsequent disolving by water has formed many karst and cave systems.

Silurian Period

408 - 360 mya

 

Warm shallow continental seas provide a hospitable environment for marine life of all kinds. Coral reefs made their first appearance during this time, and first bony fish appear. Brachiopods, bryozoa, molluscs, and trilobites abundant and diverse.

In eastern Tasmania the water was deeper and fossils are sparse.

The first fossil records of vascular plants appear.

Devonian Period

360 - 325 mya

 

Marine faunas continue to be dominated by bryozoa, diverse and abundant brachiopods and corals. In the late Devonian the lobe-finned fish appear, giving rise to the first tetrapods (four-legged creatures).

By the end of the Devonian, the first seed-forming plants appear. Primitive arthropods co-evolve with diversified terrestrial vegetation structure. Vertebrates and arthropods solidly established on the land.

Great Dividing Range in eastern Australia forms by collision of two tectonic plates. This major mountain building event generated a tremendous amount of heat resulting in widespread melting in the crust deep below the surface. The heat produced magma (molten rock), which gradually rose bouyantly then cooled at considerable depth below the surface. It is this cooled magma that formed the spectacular granites extending from the Tasman Peninsula to Wilsons Promontory in Victoria, and including the Freycinet Peninsula.

Carboniferous Period

325 - 286 mya

 

Amphibians diverse and common (more so than they are today). Evolution of first reptiles and conifers (gymnosperms).

Significant accumulations of coal begin to occur in northern hemisphere.

Permian Period

286 - 250 mya

 

Towards end of Permian, first archosaurs appear. Some archosaurs would evolve into more advanced types, eventually into dinosaurs.

Dense fossil shell deposits form at Fossil Cliffs on Maria Island. The site contains large drop stones in layers near the fossils, indicating that icebergs melted and dropped the eroded material.

The Tasmanian and eastern Australian landmass slowly uplifts. As the sea retreats and the climate warms up, the Tasmania Basin is drained by broad meandering river systems. Dinosaurs roam the Earth, though interestingly dinosaur fossils have not been found in Tasmania. Tree ferns similar to those found today are abundant.

Triassic Period

250 - 208 mya

 

The Earth's major extinction event marks the Permian-Triassic boundary. 90% or more of all marine species became extinct. Appearing at the end of the Permian were the first cynodonts, which would go on to evolve into mammals during the Triassic.

Towards the end of the Triassic the supercontinent Pangaea began to break into Laurasia to the north and Gondwana to the south.

Australia's oldest deposits of black coal, found in NSW and Queensland, were laid down between 225 and 180 mya.

Jurassic Period

208 - 144 mya

 

Ancient flora, such as conifers, ferns, cycads, gingkos, lycopods, horsetails - some survive today. Fossils of ferns, conifers and cycads occur. Globally climate warm and wet.

Between 170 and 180mya Gondwana begins a long period of break up, molten rock (magma) is forced up though the Earth’s crust and intruded sideways. The cooled and solidified magma becomes the dolerite which forms many of the spectacular columnar mountain tops and sea cliffs so typical of eastern Tasmania, such as at Ben Lomond, Mt Wellington and Tasman Peninsula.

Basalt eruption buries Jurassic forest at Lune River in Tasmania’s far south.

Coals mined in Tasmania are typically between 140 and 180 million years old.

Cretaceous Period

144 - 65 mya

 

High sea levels cause widespread flooding by sea - Great Artesian Basin forms.

Between 100 and 80 mya the climate was mostly warm again. The Terminal Cretaceous Event 65 mya is accompanied by sudden cooling, many extinctions (including extinction of dinosaurs), volcanic activity, possibly caused by asteroid/comet impact.

Gondwana continues to fragment. 125 mya Africa separates from Antarctica. India separates from Antarctica and Australia and moves north at 20cm a year; 100 mya Africa separates from South America; 80 mya New Zealand separates from Australia as Tasman Sea forms. Australia stays attached to Antarctica.

100 mya flowering plants evolve; 90 mya flowering plants migrate to all continents and begin to compete with conifers; 80 mya southern conifers dominant in Australia - Huon Pine, Phyllocladus, Callitris. First Proteaceae in Australia. Nothofagus arrives via Antarctica and South America, but does not reach Africa.

Tertiary Period

65 - 1.6 mya

Palaeocene

65 - 58 mya

Mainly warm and wet. 50 mya India collides with Asia and forms Himalayas. Seafloor spreading in Great Australian Bight causes Australia to separate from Antarctica 45 mya. Tasmania hangs on to Antarctica. South Tasman Rise continued to provide migration route to Antarctica until 45 mya.

First occurrence of Casuarinas, Banksia, Myrtaceae, Restioneaceae, Winteraceae and Epacridaceae

Eocene

58 - 40 mya

Grass pollen appears.

Australia severes its final link with Gondwana about 45 mya, carrying with it its cargo of Gondwanan plants which evolve in isolation for 30 million years. Rich sub-tropical rainforest covers much of Australia (now confined to N.E. Queensland, New Guinea and New Caledonia.)

Oligocene

40 - 24 mya

Circum-polar current forms. Climate becomes cooler and drier. First glaciers on Antarctica. Drake Passage opens, severing connection between South America and Antarctica. Tasmania carried north on Australian plate from about 65º S.

Temperate rainforest widespread with much Nothofagus. (Also in Antarctica and South America). 25 mya Acacia and Eucalyptus pollen first recognised in Australia.

Miocene

24 - 5.3 mya

Warm and wet for a short period initially.

20 mya isolation and cooling of Antarctica; 17 mya Antarctic flora succumbs to cold.

15 mya Australian plate (of which New Guinea is at northern leading edge) collides with southern Asia forming the New Guinea Highlands.

15 mya change from closed forest to wet sclerophyll forest, dry forest to open woodland and grasses. Eucalypts, acacias, casuarinas, grasses become dominant; 10 mya Australia drifts north at 6-7cm/yr, becoming dryer and arriving in sub-tropics. Fire becomes important factor in Australian ecosystem. Cold, dry, arid period.

Pliocene

5.3 - 1.6 mya

Antarctica freezes over. Brief warm period, then colder again. Northern ice cap forms.

Australian plate collides with Timor region. Migration of plants and animals from south-east Asia into Australia. Tasmania arrives at latitude 42ºS. Cool, temperate and moist.

5 mya sub-tropical forest species migrate to refuges in Queensland and New Guinea. Invasion by Asian plants from north. Myrtaceae dominate. 2 mya dry sclerophyll, woodlands and deserts expand.

Quaternary Period

1.6 - 0 mya

Pleistocene

1.6 - 0.01 mya

Several glacial stages shape the current character of Tasmanian highlands. Sea levels rise and fall many times. Climate drying. Humans arrive in Australia about 60,000 years.

Intermittent land bridge across Bass Strait.

Megafauna throughout Europe, Africa, North America and Australia but becomes extinct about 50 000 years ago.

Humans cross into Tasmania at least 36 000 years ago and have major impact on flora through the use of fire.

Holocene

0.01 mya - present

Recent glacial period ends about 12000 years ago, sea rises to current level about 6000 years ago, isolating Tasmania from Australia. Dingoes brought into Australia by Aboriginal people about 4000 years ago, but Bass Strait does not allow their entry into Tasmania. Tasmanian Aboriginal people isolated from mainland counterparts.

Sand transported landwards by rising seas and down rivers, producing spectacular landforms such as the isthmus features on Bruny Island, Maria Island and at Freycinet Peninsula.

Modern humans have major impact on global environment. Continental movement continues.