Polyorogenic history of the East Greenland Caledonides
Polyorogenic history of the East Greenland Caledonides (in The Greenland Caledonides; evolution of the northeast margin of Laurentia, A. K. Higgins (editor), Jane A. Gilotti (editor) and M. Paul Smith (editor))
Memoir - Geological Society of America (2008) 202: 55-72
- Archean
- Arctic region
- Caledonian Orogeny
- Caledonides
- East Greenland
- gneisses
- granites
- Greenland
- Grenvillian Orogeny
- igneous rocks
- metabasalt
- metaigneous rocks
- metamorphic rocks
- metasedimentary rocks
- orogeny
- orthogneiss
- overprinting
- Paleoproterozoic
- Paleozoic
- plutonic rocks
- polyphase processes
- Precambrian
- Proterozoic
- supracrustals
- thrust sheets
- upper Precambrian
The Caledonian orogen of East Greenland contains remnants of Archean, Paleo-proterozoic, late Mesoproterozoic, and early Neoproterozoic rocks that occur within far-traveled thrust sheets, and bear witness to a complex polyorogenic history of the region prior to Caledonian orogenesis. Archean and Paleoproterozoic complexes consist mainly of granitoid orthogneisses. A succession of Paleoproterozoic tholeiitic metabasalts is present in some of the foreland windows. A major unit of late Mesoproterozoic metasedimentary rocks (Krummedal supracrustal sequence) contains early Neoproterozoic (ca. 950 Ma) as well as Caledonian granites. There is evidence for Archean (ca. 2800-2600 Ma), Paleoproterozoic (2000-1750 Ma), and late Grenvillian (ca. 950 Ma) deformation and metamorphism, but Caledonian overprinting complicates the study of these events. This paper presents a broad overview of the various rock units with structural, geochemical, and geochronologic data. The Paleoproterozoic metabasaltic rocks from the foreland windows are described in more detail.
