Journal article
Geochemical and Geochronological Evidence That the North-East Greenland Ultrahigh-Pressure Terrane Is Laurentian Crust
The Journal of geology, Vol.119(5), pp.439-456
09/01/2011
DOI: 10.1086/660867
Abstract
Coesite-bearing gneiss and eclogite constitute the North-East Greenland ultrahigh-pressure (UHP) terrane on a small island located at approximately 78...00'N, 18...54'W in the North Atlantic Ocean. The island lies on the eastern margin of the much larger Caledonian North-East Greenland high-pressure (HP) eclogite province. This eclogite province is composed of juvenile Paleoproterozoic crust dominated by 1.85-2.0-Ga calc-alkaline magmatic-arc rocks that were deformed and then intruded by a suite of anorogenic granites at approximately 1.75 Ga. These orthogneisses can be traced to the foreland of the Caledonian orogen before they disappear under the ice sheet and thus are taken to be part of Laurentia. Whole-rock and trace-element geochemistry from six UHP gneisses demonstrate that the samples represent the more mafic parts of the calc-alkaline arc seen in the HP eclogite province. U-Pb ion probe ages of zircon from four gneisses add to the evidence that the protoliths of the UHP rocks are Paleoproterozoic. Two clinopyroxene-bearing intermediate orthogneisses have ages of and Ma, while two foliated, garnet-bearing metagranitoid samples give upper-intercept ages of and Ma that match the age of anorogenic granites in the HP province. Trace-element analysis of zircon confirms that the ages are magmatic. Although UHP metamorphism on Rabbit Ears Island is 25-55 m.yr. younger than Caledonian HP metamorphism in the greater North-East Greenland eclogite province, the two terranes share the same original provenance and tectonic setting on the margin of Laurentia in the overriding plate of the collision with Baltica. These results support a model of intracratonic subduction for the formation of UHP metamorphism in North-East Greenland. (ProQuest: ... denotes formulae/symbols omitted.)
Details
- Title: Subtitle
- Geochemical and Geochronological Evidence That the North-East Greenland Ultrahigh-Pressure Terrane Is Laurentian Crust
- Creators
- Jane A GilottiWilliam C McClelland
- Resource Type
- Journal article
- Publication Details
- The Journal of geology, Vol.119(5), pp.439-456
- Publisher
- University of Chicago, acting through its Press
- DOI
- 10.1086/660867
- ISSN
- 0022-1376
- eISSN
- 1537-5269
- Language
- English
- Date published
- 09/01/2011
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229162702771
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