Constraining crystallization conditions during the Cambro-Ordovician post-collisional magmatism at Araçuaí belt (SE Brazil): Zircon as key petrologic witness

Fernandes, Clarisse Monteiro; Teixeira, Patrícia Anselmo Duffles; Mendes, Júlio Cézar

doi:10.1016/j.jsames.2021.103235

Cited by 4 publications

(1 citation statement)

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“…The slight increase in Yb/U (Figure 9) in these younger zircons suggests the addition of MORB-like or juvenile mantle-derived magmatism, which is consistent with the type of magmatism accompanying Rodinia rifting. Zircon trace element chemistry, particularly of the lanthanoids, uranium (U), thorium (Th), yttrium (Y), oxygen (O), and hafnium (Hf), can be useful in understanding their petrogenesis and provenance, and for crustal evolution [70,[110][111][112][113][114][115]. Whereas lanthanoid geochemistry is not thought to be particularly useful in assisting with provenance determinations [116], it is useful at a broader scale for understanding the continental history of a region.…”

Section: Zircon Trace Element Geochemistrymentioning

confidence: 99%

Early Evolution of the Adelaide Superbasin

et al. 2022

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Continental rifts have a significant role in supercontinent breakup and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of its early evolution and place within the Rodinian supercontinent. In the past decade, our understanding of rift and passive margin development, mantle plumes and their role in tectonics, geodynamics of supercontinent breakup, and sequence stratigraphy in tectonic settings has advanced significantly. However, literature on the early evolution of the Adelaide Superbasin has not been updated to reflect these advancements. Using new detrital zircon age data for provenance, combined with existing literature, we examine the earliest tectonic evolution of the Adelaide Superbasin in the context of our modern understanding of rift system development. A new maximum depositional age of 893 ± 9 Ma from the lowermost stratigraphic unit provides a revised limit on the initiation of sedimentation and rifting within the basin. Our model suggests that the basin evolved through an initial pulse of extension exploiting pre-existing crustal weakness to form half-grabens. Tectonic quiescence and stable subsidence followed, with deposition of a sourceward-shifting facies tract. Emplacement and extrusion of the Willouran Large Igneous Province occurred at c. 830 Ma, initiating a new phase of rifting. This rift renewal led to widespread extension and subsidence with the deposition of the Curdimurka Subgroup, which constitutes the main cyclic rift sequence in the Adelaide Superbasin. Our model suggests that the Adelaide Superbasin formed through rift propagation to an apparent triple junction, rather than apical extension outward from this point. In addition, we provide evidence suggesting a late Mesoproterozoic zircon source to the east of the basin, and show that the lowermost stratigraphy of the Centralian Superbasin, which is thought to be deposited coevally, had different primary detrital sources.

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