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Mantle upwelling after Gondwana subduction death explains anomalous topography and subsidence histories of eastern New Zealand and West Antarctica

Sutherland, Rupert and Spasojevic, Sonja and Gurnis, Michael (2010) Mantle upwelling after Gondwana subduction death explains anomalous topography and subsidence histories of eastern New Zealand and West Antarctica. Geology, 38 (2). pp. 155-158. ISSN 0091-7613. http://resolver.caltech.edu/CaltechAUTHORS:20100224-111903665

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Abstract

West Antarctica and adjacent seafloor have topographic elevations 0.5–1.2 km greater than expected from models of lithospheric age and crustal structure. Ocean crust near New Zealand has no equivalent depth anomaly, but tectonic subsidence histories from Campbell Plateau petroleum wells show anomalously high subsidence rates during the Paleogene, and total subsidence 0.5–0.9 km greater than expected from rift basin models. Geophysical and geochemical anomalies suggest that upward mantle flow supports the anomalous topography beneath Antarctica, and the Campbell Plateau subsidence history indicates that topographic support mechanisms were long lived (>80 Ma) and recoverable over a period of ~30 m.y. as plate motions moved New Zealand from Antarctica. We construct models of Late Cretaceous and Cenozoic mantle flow with a slab graveyard and upwelling above that is initially rooted at 1000–1500 km depth. Our models match topography and subsidence history anomalies, and are consistent with mantle seismic wave speed anomalies and the geoid. We suggest that when thermally driven slab downwelling ceased ca. 100 Ma, low-density material that was fertilized within a broad zone in the lower mantle during the previous ~400 m.y. of Gondwana subduction was released and able to rise. Mantle upwelling from depths of 700–1500 km, lasting for periods of ~100–200 m.y., with enriched chemistry related to the prior subduction history may be a general process that follows subduction death, and has not previously been recognized.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1130/G30613.1DOIUNSPECIFIED
http://geology.gsapubs.org/content/38/2/155PublisherUNSPECIFIED
Additional Information:© 2010 Geological Society of America. Received 14 August 2009; accepted 9 September 2009. Funded by the New Zealand Foundation for Research Science and Technology and National Science Foundation grant EAR-0810303. Contribution 10027 of the Division of Geological and Planetary Sciences and contribution 118 of the Tectonics Observatory, California Institute of Technology.
Group:Caltech Tectonics Observatory
Funders:
Funding AgencyGrant Number
New Zealand Foundation for Research Science and TechnologyUNSPECIFIED
NSFEAR-0810303
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences10027
Caltech Tectonics Observatory118
Record Number:CaltechAUTHORS:20100224-111903665
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20100224-111903665
Official Citation:Rupert Sutherland, Sonja Spasojevic, and Michael Gurnis Mantle upwelling after Gondwana subduction death explains anomalous topography and subsidence histories of eastern New Zealand and West Antarctica Geology February 2010, v. 38, p. 155-158, doi:10.1130/G30613.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17575
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:02 Mar 2010 23:47
Last Modified:26 Dec 2012 11:47

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