Provenance of the Early Permian Nambucca block (eastern Australia) and implications for the role of trench retreat in accretionary orogens

Shaanan, Uri, Rosenbaum, Gideon and Wormald, Richard (2015) Provenance of the Early Permian Nambucca block (eastern Australia) and implications for the role of trench retreat in accretionary orogens. Geological Society of America Bulletin, 127 7-8: 1052-1063. doi:10.1130/B31178.1


Author Shaanan, Uri
Rosenbaum, Gideon
Wormald, Richard
Title Provenance of the Early Permian Nambucca block (eastern Australia) and implications for the role of trench retreat in accretionary orogens
Journal name Geological Society of America Bulletin   Check publisher's open access policy
ISSN 0016-7606
1943-2674
Publication date 2015-07
Sub-type Article (original research)
DOI 10.1130/B31178.1
Volume 127
Issue 7-8
Start page 1052
End page 1063
Total pages 12
Place of publication Boulder, CO, United States
Publisher Geological Society of America
Collection year 2016
Language eng
Abstract The New England orogen of eastern Australia is characterized by tight orogenic curvatures (oroclines). Oroclinal bending commenced in the Early Permian during a period of extension that involved crustal melting, widespread emplacement of S-type granitoids, high-temperature metamorphism, exhumation of metamorphic complexes, extensional faulting, and development of rift basins. One of these basins is the Early Permian Nambucca block, which is situated in the “core” of the oroclinal structure, but its origin and time of deposition are poorly constrained. Here, we present new U-Pb ages of detrital zircons from the Nambucca block, which include age populations as young as 299 and 285 Ma, confirming the Early Permian deposition of the succession. Additional Devonian–Carboniferous and Precambrian ages indicate that detritus was mainly derived from the New England subduction complex and cratonic Gondwana. The range of ages suggests that the Nambucca Basin received detritus from both arc and continent and that deposition occurred in a back-arc setting. Given the coeval formation of the Nambucca Basin and the New England oroclines, we propose that this back-arc extensional basin was controlled by trench retreat, which resulted in “Mediterranean-style” orogenic curvatures along the plate boundary of eastern Gondwana. The recognition of a genetic link between oroclinal bending and back-arc extension may explain how accretionary orogens, such as the eastern Australian Tasmanides, were able to obtain an anomalous width without a substantial contribution of accreted exotic terranes. A similar mode of tectonism may have played an important role in other accretionary orogens.
Keyword Early Permian Nambucca block
Oroclines
Gondwana
Trench retreat
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2016 Collection
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 7 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 5 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Fri, 20 Feb 2015, 08:56:42 EST by Dr Gideon Rosenbaum on behalf of School of Earth Sciences