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Long-wavelength tilting of the Australian continent since the Late Cretaceous

DiCaprio, Lydia and Gurnis, Michael and Müller, R. Dietmar (2009) Long-wavelength tilting of the Australian continent since the Late Cretaceous. Earth and Planetary Science Letters, 278 (3-4). pp. 175-185. ISSN 0012-821X. http://resolver.caltech.edu/CaltechAUTHORS:20090629-112818624

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Abstract

Global sea level and the pattern of marine inundation on the Australian continent are inconsistent. We quantify this inconsistency and show that it is partly due to a long wavelength, anomalous, downward tilting of the continent to the northeast by 300 m since the Eocene. This downward tilting occurred as Australia approached the subduction systems in South East Asia and is recorded by the progressive inundation of the northern margin of Australia. From the Oligocene to the Pliocene, the long wavelength trend of anomalous topography shows that the southern margin of Australia is characterized by relative subsidence. We quantify the anomalous topography of the Australian continent by computing the displacement needed to reconcile the interpreted pattern of marine incursion with a predicted topography in the presence of global sea level variations. On the southern margin, long wavelength subsidence was augmented by at least 250 m of shorter wavelength anomalous subsidence, consistent with the passage of the southern continental margin over a north–south elongated, 500 km wide, topographic anomaly approximately fixed with respect to the mantle. The present day reconstructed position of this depth anomaly is aligned with the Australian Antarctic Discordance and is consistent with the predicted passage of the Australian continent over a previously subducted slab. Both the long-wavelength continental tilting and smaller-scale paleo-topographic anomaly on the southern Australian margin may have been caused by subduction-generated dynamic topography. These new constraints on continental vertical motion are consistent with the hypothesis that mantle convection induced topography is of the same order of magnitude as global sea level change.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.epsl.2008.11.030DOIUNSPECIFIED
Additional Information:© 2008 Elsevier B.V. Received 22 December 2007; revised 2 November 2008; accepted 22 November 2008. Editor: R.D. van der Hilst. Available online 21 January 2009. All figures except Figs. 2, 3 and 8 were generated using GMT (Wessel and Smith, 1991). We would like to thank Christian Heine who provided the basin outlines and the help and advice of Christopher DiCaprio. Lydia DiCaprio was funded by the Australian Research Council Australian Postgraduate Award administered by the University of Sydney. This work represents contribution 8997 of the Division of Geological and Planetary Sciences, California Institute of Technology, and contribution 97 of the Tectonics Observatory. We thank M. Sandiford and an anonymous reviewer for their reviews that significantly improved this manuscript.
Group:Caltech Tectonics Observatory
Funders:
Funding AgencyGrant Number
Australian Research CouncilUNSPECIFIED
University of SydneyUNSPECIFIED
Subject Keywords:Australia; Cenozoic; topography; subduction; dynamic topography; global sea level; Australian Antarctic Discordance; paleo-shoreline
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences8997
Caltech Tectonics Observatory97
Record Number:CaltechAUTHORS:20090629-112818624
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20090629-112818624
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14454
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Aug 2009 22:20
Last Modified:26 Dec 2012 11:03

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