Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Harald Furnes,1*Maarten de Wit,2,3Hubert Staudigel,4Minik Rosing,5Karlis Muehlenbachs6
A sheeted-dike complex within the 3.8-billion-year-old Isuasupracrustal belt (ISB) in southwest Greenland provides theoldest evidence of oceanic crustal accretion by spreading. Thegeochemistry of the dikes and associated pillow lavas demonstratesan intraoceanic island arc and mid-ocean ridge–like setting,and their oxygen isotopes suggest a hydrothermal ocean-floor–typemetamorphism. The pillows and dikes are associated with gabbroicand ultramafic rocks that together make up an ophiolitic association:the Paleoarchean Isua ophiolite complex. These sheeted dikesoffer evidence for remnants of oceanic crust formed by sea-floorspreading of the earliest intact rocks on Earth.
1 Centre for Geobiology and Department of Earth Science, University of Bergen, Bergen, Norway. 2 Africa Earth Observatory Network (AEON) and Department of Geological Sciences, University of Cape Town, Rondebosch 7700 South Africa. 3 GeoForschungsZentrum (GFZ)–Potsdam, Telegraphenberg, Potsdam, Germany. 4 Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0225, USA. 5 Nordic Centre for Earth Evolution and Geological Museum, University of Copenhagen, 1350, Københagen K, Denmark 6 Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada.
* To whom correspondence should be addressed. E-mail: harald.furnes{at}geo.uib.no
The editors suggest the following Related Resources on Science sites:
In Science Magazine
TECHNICAL COMMENTS
Allen P. Nutman and Clark R. L. Friend (2 November 2007) Science318 (5851), 746c.
[DOI: 10.1126/science.1144148] |Abstract »|Full Text »|PDF »
TECHNICAL COMMENTS
Warren B. Hamilton (2 November 2007) Science318 (5851), 746d.
[DOI: 10.1126/science.1144931] |Abstract »|Full Text »|PDF »
TECHNICAL COMMENTS
Harald Furnes, Maarten de Wit, Hubert Staudigel, Minik Rosing, and Karlis Muehlenbachs (2 November 2007) Science318 (5851), 746e.
[DOI: 10.1126/science.1144231] |Abstract »|Full Text »|PDF »
NEWS OF THE WEEK
Richard A. Kerr (23 March 2007) Science315 (5819), 1650b.
[DOI: 10.1126/science.315.5819.1650b] |Summary »|Full Text »|PDF »
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Accretionary orogens through Earth history.
P. A. Cawood, A. Kroner, W. J. Collins, T. M. Kusky, W. D. Mooney, and B. F. Windley (2009)
Geological Society, London, Special Publications
318, 1-36
|Abstract »|Full Text »|PDF »
Metamorphic patterns in orogenic systems and the geological record.
M. Brown (2009)
Geological Society, London, Special Publications
318, 37-74
|Abstract »|Full Text »|PDF »
Archaean crustal growth processes in southern West Greenland and the southern Superior Province: geodynamic and magmatic constraints.
A. Polat, R. Kerrich, and B. Windley (2009)
Geological Society, London, Special Publications
318, 155-191
|Abstract »|Full Text »|PDF »
Mineral evolution.
R. M. Hazen, D. Papineau, W. Bleeker, R. T. Downs, J. M. Ferry, T. J. McCoy, D. A. Sverjensky, and H. Yang (2008)
American Mineralogist
93, 1693-1720
|Abstract »|Full Text »|PDF »
Earth's Oldest Rocks.: MARTIN J. VAN KRANENDONK, R. HUGH SMITHIES, and VICKIE C. BENNETT, Editors. Pp. 1307. 2007. Developments in Precambrian Geology. 15. El-sevier. Amsterdam. ISBN-13: 978-0-444-52810-0, ISBN-10: 0-444-52810-5. Price: USD150..
M. de Wit (2008)
Economic Geology
103, 1079-1086
|Full Text »|PDF »
Role of oceanic plateaus in the initiation of subduction and origin of continental crust.
3.8-billion-year-old Isua supracrustal belt (ISB) in southwest Greenland provides the oldest evidence of oceanic crustal accretion by spreading. The geochemistry of the dikes and associated pillow lavas demonstrates an intraoceanic island arc and mid-ocean ridge–like setting, and their oxygen isotopes suggest a hydrothermal ocean-floor–type metamorphism. The pillows and dikes are associated with gabbroic and ultramafic rocks that together make up an ophiolitic association: the Paleoarchean Isua ophiolite complex. These sheeted dikes offer evidence for remnants of oceanic crust formed by sea-floor spreading of the earliest intact rocks on Earth. 
