Jurassic arc: reconstructing the lost world of eastern Gondwana
Date
2021
Authors
Foley, E.K.
Henderson, R.A.
Roberts, E.M.
Kemp, A.I.S.
Todd, C.N.
Knutsen, E.M.
Fisher, C.
Wainman, C.C.
Spandler, C.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Geology (Boulder), 2021; 49(11):1391-1396
Statement of Responsibility
Elliot K. Foley, R.A. Henderson, E.M. Roberts, A.I.S. Kemp, C.N. Todd, E.M. Knutsen, C. Fisher, C.C. Wainman and Carl Spandler
Conference Name
DOI
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.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© 2021 Geological Society of America. For permission to copy, contact editing@geosociety.org.