Jurassic Arc: reconstructing the lost world of eastern Gondwana

Foley, Elliot K., Henderson, R.A., Roberts, E.M., Kemp, A.I.S., Todd, C.N., Knutsen, E.M., Fisher, C., Wainman, C.C., and Spandler, Carl (2021) Jurassic Arc: reconstructing the lost world of eastern Gondwana. Geology, 49 (11). pp. 1391-1396.

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Abstract

The tectonic setting of the Australian sector of the eastern Gondwanan margin during the Jurassic and Cretaceous is enigmatic. Whether this involved convergent tectonism and a long-lived continental magmatic arc or rift-related extension unrelated to subduction is debated. The paucity of Australian Jurassic–Cretaceous igneous outcrops makes resolving these competing models difficult. We used the detrital zircon record of the Jurassic–Cretaceous Great Australian Superbasin (GAS) as a proxy for igneous activity. We attribute the persistent magmatism recorded in GAS sedimentary fill throughout the Mesozoic to ca. 95 Ma to continuation of the established Paleozoic continental arc system. The detrital zircon record signals short (~10 m.y.) pulses of elevated Jurassic and Cretaceous magmatic activity and strongly positive εHf values, indicating juvenile crust or mantle-derived magmatism. Margin reconstruction indicates sustained continental growth at rates of at least ~55 km3 km–1 m.y.–1, mainly to the tract now represented by submerged northern Zealandia, due to the retreat of this arc system. We posit that arc retreat was a key factor in rapid crust generation and preservation, and that continental sedimentary systems globally may host cryptic records of juvenile crustal addition that must be considered in estimating crustal growth rates along convergent plate margins.

Item ID: 72655
Item Type: Article (Research - C1)
ISSN: 1943-2682
Copyright Information: © 2021 Geological Society of America. F
Funders: Australian Research Council (ARC)
Projects and Grants: ARC Jurassic Arc Project DP180102851
Date Deposited: 28 Feb 2022 02:51
FoR Codes: 37 EARTH SCIENCES > 3705 Geology > 370509 Sedimentology @ 50%
37 EARTH SCIENCES > 3705 Geology > 370502 Geochronology @ 50%
SEO Codes: 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100%
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