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Mafic volcanic rocks on King Island, Tasmania: evidence for 579 Ma break-up in east Gondwana


Meffre, S and Direen, N and Crawford, AJ and Kamenetsky, VS, Mafic volcanic rocks on King Island, Tasmania: evidence for 579 Ma break-up in east Gondwana, Precambrian Research, 135, (3) pp. 177-191. ISSN 0301-9268 (2004) [Refereed Article]

DOI: doi:10.1016/j.precamres.2004.08.004


The eastern coast of King Island in southeastern Australia exposes a thick, well-preserved sequence of latest Neoproterozoic volcanic, and related shallow intrusive rocks. These rocks are associated with shallow marine carbonates and siltstones and pass up into massive conglomerates representing a marine flooding event and unconformity, during continental break-up and subsequent volcanic passive margin formation. Unusual differentiated sills (Grimes Intrusive suite) with extreme internal variation (wehrlite to andesite compositions) intrude deformed Proterozoic metasediments of the Rodinian basement. A thin, basal tholeiitic basaltic volcanic unit (City of Melbourne Volcanics) is less contaminated than the underlying sills, and preceded eruption of a thick sequence of highly depleted picritic pillows, sub-aerial flows and hyaloclastites (Shower Droplet Volcanics). The picrite sequence is overlain by thick tholeiitic basalts and reworked volcanogenic conglomerates (Bold Head Formation) that show a strong compositional similarity to enriched mid ocean ridge basalts. Both the picrites and the upper tholeiitic basalts are not crustally contaminated and have an Nd-Sm isochron age of 579 ± 16 Ma with initial εNd of +4.2. The lithostratigraphy and range of compositions represented are analogous to early magmatism associated with continental break-up and volcanic passive margin formation, including voluminous Seaward Dipping Reflector Sequences, in the Mesozoic North Atlantic volcanic margins. © 2004 Elsevier B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Meffre, S (Professor Sebastien Meffre)
UTAS Author:Direen, N (Dr Nicholas Direen)
UTAS Author:Crawford, AJ (Professor Anthony Crawford)
UTAS Author:Kamenetsky, VS (Professor Vadim Kamenetsky)
ID Code:32658
Year Published:2004
Web of Science® Times Cited:55
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2004-08-01
Last Modified:2011-11-25

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