The Earth’s crust in Western Australia originated more than 3.7 billion years ago as Archean cratons. These ancient parts of the continent grew as molten rock cooled and joined together. Over time, they formed the North and West Australian cratons during the Proterozoic Eon, which lasted from 2.5 billion to 538.8 million years ago. Later, in the Cambrian Period (about 530 million years ago), they became part of the supercontinent Gondwana.
In the Cretaceous Period Western Australia’s western margin separated from India and Africa (130 million years ago) and its southern margin from Antarctica (84 million years ago). Western Australia is now part of the present-day Australian Plate, which around 23 million years ago has begun to collide with the Sunda Plate along its northwestern margin.
A wealth of mineral deposits and petroleum resources formed during the 3.7-billion-year geological history of Western Australia. World-class mineral deposits include gold, iron, nickel, heavy mineral sands, diamonds and bauxite. Petroleum also abounds in the giant fields of the North West Shelf and smaller fields onshore.
Geological history of Western Australia
Watch our animation of the Geological map of WA 2015 through time.
This animation and our book series WA Unearthed are aimed at geologists and are suitable for anyone wanting to get a quick understanding of the State’s geology or economic potential of specific terranes or time periods.
Find further information on the WA Unearthed series on the DEMIRS eBookshop page or follow the links below to access each book in the series.
A Paleozoic perspective of Western Australia
Mesozoic transformation of Western Australia: rifting and breakup of Gondwana
Geological icons of Western Australia
Earth’s oldest zircon crystals at Jack Hills
Jack Hills (also known as Erawondoo Hill) traces the spine of a narrow greenstone belt in the Narryer Terrane in the northern part of the Yilgarn Craton. A few localities in the greenstone belt are world famous for preserving the oldest minerals on Earth — grains of zircon up to 4.37 billion years old.
Jack Hills is a registered Geoheritage Site and there is no public access without permission from leaseholders.
Old zircons and early evolution of the Yilgarn Craton
Deep time in the Murchison region, Western Australia
Australia’s oldest fossils found in the Pilbara
In the Trendall area of the Pilbara Craton, there are Archean stromatolites, which are ancient rock structures linked to some of the earliest life on Earth. Trendall is a State Geoheritage Reserve, and you need permission from DEMIRS to visit.
Eastern Goldfields gold and nickel booms
Archean granite-greenstones in the Eastern Goldfields are host to world-class nickel and gold deposits. Gold was discovered in the area in 1893 and is still mined in the Superpit from the Golden Mile Dolerite. Nickel was discovered in the 1960s and led to a nickel boom.
Yilgarn Craton: geological setting of gold and nickel deposits in the Eastern Goldfields
Hamersley Ranges iron ore deposits that changed Australia’s economy
Banded iron formations (BIF) are rocks made up of colourful layers, including green, blue, red, and orange jasper, along with shiny golden tiger eye. Some types, which are rich in hematite, are mined as a source of iron.
The Hamersley Ranges are host to giant iron ore deposits within folded layers of 2.5-billion-year-old BIF. The Mount Whaleback Mine is the largest opencut iron ore mine in the world, with a pit length of 5.5 kilometres.
Iron-formations: a mineral systems analysis
Fortescue-Hamersley, 2022: Geological Information Series
Stratigraphy and structure of Mining Area C
An ancient barrier reef in the Kimberley region
In northern Western Australia lie a rugged limestone ranges that stretch for 350 kilometres along the Canning. The Devonian Great Barrier Reef are famous for being one of the best examples of an ancient coral reef system. These reef limestones are also important because they have the potential to hold valuable economic resources. Some zinc-lead deposits and a small oil field have already been found in these rocks, making them an ongoing focus for mining and energy exploration.
Devonian reef complexes of the Canning Basin, Western Australia
Western Australia's fossil great barrier reef
Pinnacles of limestone in Nambung National Park
Pinnacles of limestone stand like sentinels in the sandy desert of the Nambung National Park, located about 200 kilometres north of Perth. Their mode of formation is still the subject of debate but is most likely due to karst dissolution of the limestone more than 30,000 years ago.
Shark Bay’s living stromatolites
Stromatolites are special because they are some of the oldest and most diverse living organisms on Earth. The present-day stromatolites grow in the calm, salty waters of Shark Bay in the Gascoyne region of Western Australia, now a World Heritage Area. These modern stromatolites are very similar to ancient ones. Archean stromatolites first appeared 3.4 billion years ago and are the oldest known fossils on Earth.
Spinifex-textured komatiites in Archean granite–greenstones
Spinifex-textured komatiites are rocks that formed during the Archean era in volcanic greenstone belts. These rocks are very rich in magnesium, and their unique chemistry hasn’t been found in rocks younger than 2.5 billion years old.
Komatiite-hosted Ni-Cu-PGE mineral systems
Geology of Rottnest Island
Rottnest Island reveals evidence of changing sea levels over the past 140,000 years, with periods when the sea was both higher and lower than today. At Fairbridge Bluff, ancient corals that grew around 132,000 years ago are now exposed well above the high tide mark, showing that sea levels were several metres higher at the time. Most of the island is made of limestone that originally formed on a wide, open plain that stretched 20 km further west.
