TY - CHAP

T1 - Zircon geochronology from the Kangaatsiaq-Qasigiannguit region, the northern part of the 1.9-1.8 Ga Nagssugtoqidian orogen, West Greenland

AU - Thrane, Kristine

AU - Connelly, James N.

PY - 2006

Y1 - 2006

N2 - The Kangaatsiaq-Qasigiannguit region in the northern part of the Palaeoproterozoic Nagssugtoqidian orogen of West Greenland consists of poly-deformed orthogneisses and minor occurrences of interleaved, discontinuous supracrustal belts. Laser ablation ICP-MS 207Pb/ 206Pb analyses of detrital zircons from four metasedimentary rocks (supplemented by ion probe analysis of one sample) and igneous zircons from six granitoid rocks cutting metasedimentary units indicate that the supracrustal rocks in the Kangaatsiaq-Qasigiannguit (Christianshåb) region are predominantly Archaean in age. Four occurrences of metasedimentary rocks are clearly Archaean, two have equivocal ages, and only one metasedimentary unit, from within the Naternaq (Lersletten) supracrustal belt, is demonstrably Palaeoprotetozoic and readily defines a large fold complex of this age at Naternaq. The 2.9-2.8 Ga ages of detrital Archaean grains are compatible with derivation from the local basement orthogneisses within the Nagssugtoqidian orogen. The detrital age patterns are similar to those of metasediments within the central Nagssugtoqidian orogen but distinct from age patterns in metasediments of the Rinkian belt to the north, where there is an additional component of pre-2.9 Ga zircons. Synkinematic intrusive granitoid rocks constrain the ages of some Archaean deformation at 2748 ± 19 Ma and some Palaeoproterozoic deformation at 1837 ± 12 Ma.

AB - The Kangaatsiaq-Qasigiannguit region in the northern part of the Palaeoproterozoic Nagssugtoqidian orogen of West Greenland consists of poly-deformed orthogneisses and minor occurrences of interleaved, discontinuous supracrustal belts. Laser ablation ICP-MS 207Pb/ 206Pb analyses of detrital zircons from four metasedimentary rocks (supplemented by ion probe analysis of one sample) and igneous zircons from six granitoid rocks cutting metasedimentary units indicate that the supracrustal rocks in the Kangaatsiaq-Qasigiannguit (Christianshåb) region are predominantly Archaean in age. Four occurrences of metasedimentary rocks are clearly Archaean, two have equivocal ages, and only one metasedimentary unit, from within the Naternaq (Lersletten) supracrustal belt, is demonstrably Palaeoprotetozoic and readily defines a large fold complex of this age at Naternaq. The 2.9-2.8 Ga ages of detrital Archaean grains are compatible with derivation from the local basement orthogneisses within the Nagssugtoqidian orogen. The detrital age patterns are similar to those of metasediments within the central Nagssugtoqidian orogen but distinct from age patterns in metasediments of the Rinkian belt to the north, where there is an additional component of pre-2.9 Ga zircons. Synkinematic intrusive granitoid rocks constrain the ages of some Archaean deformation at 2748 ± 19 Ma and some Palaeoproterozoic deformation at 1837 ± 12 Ma.

KW - Deformation

KW - LA-ICP-MS

KW - Metasediment

KW - Nagssugtoqidian orogen

KW - Zircon

UR - http://www.scopus.com/inward/record.url?scp=33846891056&partnerID=8YFLogxK

M3 - Book chapter

AN - SCOPUS:33846891056

SN - 8778711886

SN - 9788778711885

T3 - Geological Survey of Denmark and Greenland Bulletin

SP - 87

EP - 99

BT - Precambrian Crustal Evolution and Cretaceous-Palaeogene Faulting in West-Greenland

PB - Geological Survey of Denmark and Greenland (GEUS)

ER -