Lyell Collection
Journal of the Geological Society
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (10)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Direen, N. G.
Right arrow Articles by Crawford, A. J.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Journal of the Geological Society; 2003; v. 160; issue.6; p. 985-990;
DOI: 10.1144/0016-764903-010
© 2003 Geological Society of London

Original Article

Fossil seaward-dipping reflector sequences preserved in southeastern Australia: a 600 Ma volcanic passive margin in eastern Gondwanaland

Nicholas G. Direen1,2 & Anthony J. Crawford1

1 1Centre for Ore Deposit Research, University of Tasmania, GPO Box 252-79, Hobart, Tas. 7001, Australia
2 2Present address: Continental Evolution Research Group, University of Adelaide, Adelaide, S.A. 5005, Australia (e-mail: Nick.Direen@adelaide.edu.au)

Evidence for a c. 600 Ma rifted passive margin in eastern Australia exists in the form of multiple belts of mafic volcanic rocks preserved along the western margin of the Tasman Fold Belt System, and giving rise to elongate magnetic anomalies. Outcrop, drillhole and geophysical evidence points to piles of lavas, volcaniclastic and intrusive rocks up to 6 km thick, extending for strike lengths of hundreds of kilometres in individual segments. The distinctive, unifying characteristics of these piles are apparent common formation ages (600–580 Ma), presence of early more landward transitional alkaline basalts, and more seaward abundant rift tholeiites, with high-temperature picrites and olivine-rich basalts at most localities. Despite later structural reorganization, these belts have close geochemical, geometric and lithological affinities with Mesozoic seaward-dipping reflector sequences along the North Atlantic, and northwestern Australian volcanic passive margins, and strongly imply the formation of a volcanic passive margin in eastern Gondwanaland at the close of the Neoproterozoic. Recognition of this event has implications for the position of an implied earlier rifted margin related to the break-up of Rodinia around 780 Ma. A rifting event at 600 Ma in eastern Gondwanaland helps explain both the lack of evidence for volcanism from Rodinia break-up, and a widespread 600 Ma population of inherited zircons within rocks of the Lachlan Orogen, which developed outboard of the passive margin in earliest Palaeozoic time.

Key Words: Eastern Australia • Neoproterozoic • Rodinia • seaward-dipping reflector sequences • basalts




This article has been cited by other articles:


Home page
 Journal of the Geological SocietyHome page
C. L. FERGUSSON, R. A. HENDERSON, C.M. FANNING, and I. W. WITHNALL
Detrital zircon ages in Neoproterozoic to Ordovician siliciclastic rocks, northeastern Australia: implications for the tectonic history of the East Gondwana continental margin
Journal of the Geological Society, 2007; 164: 215 - 225.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society, London, Special PublicationsHome page
A. P. M. Vaughan, P. T. Leat, and R. J. Pankhurst
Terrane processes at the margins of Gondwana: introduction
Geological Society, London, Special Publications, 2005; 246: 1 - 21.
[Abstract] [PDF]

Home page
 Geological Society, London, Special PublicationsHome page
R. A. Glen
The Tasmanides of eastern Australia
Geological Society, London, Special Publications, 2005; 246: 23 - 96.
[Abstract] [PDF]

Home page
 GeologyHome page
U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania
Geology, 2004; 32: 893 - 896.