The Yilgarn Craton
is a large craton
which constitutes the bulk of the Western Australian
land mass. It is bounded by a mixture of sedimentary basins
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.
The Yilgarn Craton appears to have been assembled between ~2.94 and 2.63 Ga by the accretion of a multitude of formerly present blocks or terranes
of existing continental crust
, most of which formed between 3.2 Ga and 2.8 Ga.
This accretion event is recorded by widespread granite
intrusions, which comprise over 70% of the Yilgarn craton; voluminous tholeiitic basalt
and komatiite volcanism
; regional metamorphism
and deformation as well as the emplacement of the vast majority of the craton's endowment in gold
events occurred in several phases, probably by accretion of continental fragments separated by pauses in subduction
, with renewed activity occurring episodically.
The craton is primarily composed of approximately 2.8 billion year old (~2.8 Ga) granite-gneiss metamorphic terrain (the... Read More