Authors / CoAuthors
Jarrett, A. | Cox, G.M. | Brocks, J.J. | Shannon, A.V. | Johnson, B. | McLennan, S. | Thorne, J. | Vinnichenko, G. | Huston, D. | Champion, D. | Henson, P.
Abstract
The Proterozoic was an important eon which saw profound changes in the geochemistry of the oceans and the first appearance and proliferation of complex life [1]. In this study we examine the relationships between organic matter and ocean geochemistry in sedimentary sequences in Northern Australia. The geobiology of the McArthur Basin has been comprehensively studied and characterised. The ca. 1.3 Ga Velkerri Formation within the Roper Superbasin is predominantly ferruginous with episodes of euxinia coupled to enhanced primary productivity [2]. In contrast, black carbonaceous shales of the ca. 1.6 Ga Fraynes and Barney Creek Formations are pervasively anoxic and euxinic [3]. The latter formation is dominated by aromatic isoprenoids, biomarkers for green and purple sulfur bacteria commonly associated with photic zone euxinia [4]. In contrast, little attention has been given to the likely coeval South Nicholson Basin and Lawn Hill Platform located directly south of the McArthur Basin, straddling the Queensland and Northern Territory border. Here we provide new insights into the paleo-environments of Paleoproterozoic and Mesoproterozoic sedimentary successions in the Lawn Hill Platform and South Nicholson Basin based on multi-proxy sedimentary geochemical analyses including biomarkers, isotopes (?13C, ?15N and ?34S) and trace metals. The results in this study while preliminary at present, demonstrate redox heterogeneity with oscillations between ferruginous and euxinic conditions broadly correlating with increases in total organic carbon content. Complexities in the data remain including potential influences of hydrothermal alteration on the thermal evolution, and mobility and abundances of trace metals in some sections of the basins. Abstract submitted to/presented at the 2018 Australian Geoscience Council Convention (AGCC)
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document
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121348
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- theme.ANZRC Fields of Research.rdf
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- EARTH SCIENCES
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- Isa superbasin
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- Roper superbasin
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- proterozoic
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- paleo-environments
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- Published_External
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2024-09-23T21:24:43
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AGCC Abstract
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geoscientificInformation
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Australian Geoscience Council Convention (AGCC) 14-18 October 2018, Adelaide, SA
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AGCC Abstract
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