Prolonged high thermal gradient metamorphism in the Curnamona Province, south-central Australia, during the latter stages of Nuna assembly

Leeuwen, Alexander T. De Vries Van; Morrissey, Laura J.; Raimondo, Tom; Hand, Martin

doi:10.1016/j.precamres.2022.106775

Cited by 5 publications

(1 citation statement)

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“…Within this configuration, the proto‐cratonic crust of the northern Gawler Craton is envisaged to have been sandwiched between two subduction systems (Figure 13). To the NE, convergence is interpreted to have led to the amalgamation of Paleoproterozoic Australia and Laurentia at around 1600 Ma (Pourteau et al, 2018), resulting in contractional deformation in NE Australia and conceivably in the Curnamona Province (De Vries Van Leeuwen et al, 2022; Pourteau et al, 2018; Volante et al, 2020), which now forms the eastern part of the South Australian Craton. To the SW, St Peter Suite arc magmatism is well documented in the interval of 1633–1608 Ma (Reid et al, 2020; Swain et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

A buried gneiss dome in the northern Gawler Craton: The record of early Mesoproterozoic (ca. 1600–1560 Ma) extension in southern Proterozoic Australia

Yu,

Hand,

Morrissey

et al. 2024

Journal Metamorphic Geology

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Mabel Creek Ridge, in the northern Gawler Craton, is a granulite‐facies domain recording early Mesoproterozoic metamorphism, flanked by less metamorphosed rocks and dissected by crustal‐scale divergent structures. The nature of early Mesoproterozoic events is poorly understood due to the lack of basement outcrop. Calculated metamorphic phase diagrams and geochronology are used to decipher the tectonic regime of a potential gneiss dome. Pressure–temperature (P–T) modelling of metapelites from five drill holes across Mabel Creek Ridge suggests it has experienced conditions of ~6.4–7.4 kbar and 800–850°C and the growth of suprasolidus cordierite after garnet indicates subsequent decompression. In situ U–Pb monazite and Lu–Hf garnet geochronology constrains the granulite‐facies metamorphism of Mabel Creek Ridge to ca. 1600–1560 Ma. In contrast, drill hole GOMA DH4 located to the north of Mabel Creek Ridge records conditions of 2.2–5.4 kbar and 710–740°C at ca. 1520 Ma, with no evidence for 1600–1560 Ma metamorphism. Our new P–T pseudosection results and geochronology data from Mabel Creek Ridge and adjacent crust, coupled with the regional seismic and airborne magnetic data, reveal that Mabel Creek Ridge represents a record of early Mesoproterozoic extension in the Gawler Craton, during which thermally perturbed lower crustal rocks were exhumed within a gneiss dome. Early Mesoproterozoic extension took place within a complex geodynamic regime resulting from the interplay between final Nuna convergence along the margin of northeast Australia at ca. 1600 Ma and subduction to the southwest at ca. 1630–1610 Ma.

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