0000000000061864
AUTHOR
I. Zibra
On thrusting, regional unconformities and exhumation of high-grade greenstones in Neoarchean orogens. The case of the Waroonga Shear Zone, Yilgarn Craton
Abstract During the Neoarchean, the dominant tectonic style progressively changed from an episodic-overturn/stagnant-lid regime to modern-style plate tectonics. The Neoarchean strengthening of continental lithosphere changed the style of deformation of orogenic belts. The case study presented here provides insights into how such transition in tectonic style occurred, a matter that is generally controversial. We present structural and metamorphic data from the c. 2660 Ma Waroonga Shear Zone (WSZ) in the Neoarchean Yilgarn orogen (Western Australia). The WSZ contains a syntectonic pluton and older, high-grade greenstones. The tectonic fabric in the pluton developed during melt-present thrusti…
On shearing, magmatism and regional deformation in Neoarchean granite-greenstone systems: Insights from the Yilgarn Craton
Abstract The structure of the Neoarchean Yilgarn Craton is dominated by craton-scale high-strain zones, mostly associated with highly-deformed elongate granitic bodies and transposed greenstone belts. These shear zones developed during widespread and prolonged magmatic activity that led to a nearly complete reworking of the felsic continental crust. The spatial, temporal and genetic relationships between such a voluminous and protracted event of crustal reworking and the development of the craton-scale shear zone network are unclear. Here, we combine new structural, geophysical and geochemical data to investigate the relationship between crustal-scale shear zones and large syntectonic pluto…
The ~2730 Ma onset of the Neoarchean Yilgarn Orogeny
The timing of the onset of an orogeny is commonly constrained indirectly, because early orogenic structures are rarely exposed, or are overprinted. Establishing the onset of an Archean orogeny is considerably more challenging, because of the more fragmented geological record and the general lack of consensus about Archean geodynamics. We combine existing tectono-stratigraphic data with new structural and geophysical datasets to establish the onset of the Neoarchean Yilgarn Orogeny (Yilgarn Craton, Western Australia). We show that the surface of the c. 2960–2750 Ma deep-marine Yilgarn greenstone sequence was uplifted, eroded and unconformably overlain by a c. 2730 Ma, syntectonic clastic seq…