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The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia. The Pilbara Craton is one of only two pristine Archaean 3.8–2.7 Ga (billion years ago) crusts identified on the Earth, along with the Kaapvaal Craton in South Africa .
Nevertheless, the oldest cratons on Earth include the Kaapvaal Craton, the Western Gneiss Terrane of the Yilgarn Craton (~2.9 – >3.2 Ga), the Pilbara Craton (~3.4 Ga), and portions of the Canadian Shield (~2.4 – >3.6 Ga). Parts of Dharwar Craton in India are greater than 3.0 Ga.
The Yilgarn Craton is a large craton that constitutes a major part of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts . Zircon grains in the Jack Hills , Narryer Terrane have been dated at ~4.27 Ga , with one detrital zircon dated as old as 4.4 Ga. [ 1 ]
The Eastern Pilbara Craton is geologically significant due to its age and the types of lithology found within it. Within the Eastern Pilbara Craton there are 2 distinct lithologic divisions: (1), early Earth crust (3.8–3.53 Ga); (2), intrusive granitic domes along with greenstone belts (3.53–3.23 Ga). [3]
The Capricorn orogeny was an orogenic event in what is now Western Australia, following the collision of the Pilbara Craton and the Glenburgh Terrane with the Yilgarn Craton during the Glenburgh orogeny. Spanning one billion years, the Capricorn orogeny is marked by widespread deformation and intracratonal reworking.
c. 2,770 Ma – Formation of Hamersley Basin on the southern margin of Pilbara Craton – last stable submarine-fluviatile environment between the Yilgarn and Pilbara prior to rifting, contraction and assembly of the intracratonic Gascoyne Complex. c. 2,750 Ma – Renosterkoppies Greenstone Belt forms on the northern edge of the Kaapvaal Craton.
There are only two locations in the world containing rock formations that are intact enough to preserve evidence of early life: the Kaapvaal Craton in Southern Africa and the Pilbara Craton in Western Australia. [4] The Dresser Formation is located in the Pilbara Craton, and contains sedimentary rock from the Paleoarchean Era.
The Australian Shield is fractured into a number of distinct blocks, including two cratons - the Pilbara Craton in the North and the Yilgarn Craton in the Southwest. These two cratons are the oldest part of the shield, both of which have been dated at more than 2.3 billion years old. [5]