Detrital zircon sedimentary provenance ages for the Eoarchaean Isua supracrustal belt southern West Greenland: Juxtaposition of an imbricated ca. 3700Ma juvenile arc against an older complex with 3920–3760Ma components

Work in 1981 on the early Archaean rocks of the Isukasia area (Ailaart, 1976) was an integral part of GGU's mapping programme of northern Godthåbsfjord, Fiskefjord and adjacent areas to the north-east. Within the Isukasia area, there was dose co-operation with Minik Rosing who was making detailed studies of certain aspects of the Isua supracrustal belt. The object of this summer's field work was to complete the study of the supracrustal belt and the central gneisses that was started last year (Nutman et al., in press), and to see as much as possibIe of the gneisses between the supracrustal belt and 65°N (fig. 18). For the mapping of the supracrustal belt, manuscript maps drawn by J. H. Allaart were an invaluable starting point. Besides regional mapping, detailed studies were made of the nature of the lithological units and the relationships between them; see Table 4 for chronology. Suites of rocks were collected for isotopic and geochemical studies. In connection with this, H. Baadsgaard spent 10 days working with the author in the area, as a guest of GGu. The results reported here supplement those given by Nutman et al. (in press).

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Early Archaean Isua supracrustal belt,West Greenland: pilot study of the Isua Multidisciplinary Research Project

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/ggub.v180.5092 ◽

1998 ◽

pp. 94-99 ◽

Cited By ~ 2

Author(s):

Peter W. U. Appel ◽

Christopher M. Fedo ◽

Stephen Moorbath ◽

John S. Myers

Keyword(s):

Pilot Study ◽

Minor Component ◽

Science Research ◽

Pilot Project ◽

Multidisciplinary Research ◽

Research Project ◽

West Greenland ◽

North East ◽

Gneiss Complex ◽

Supracrustal Belt

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Appel, P. W. U., Fedo, C. M., Moorbath, S., & Myers, J. S. (1998). Early Archaean Isua supracrustal belt,West Greenland: pilot study of the Isua Multidisciplinary Research Project. Geology of Greenland Survey Bulletin, 180, 94-99. https://doi.org/10.34194/ggub.v180.5092 _______________ The Isua belt of 3.8–3.7 Ga metavolcanic and metasedimentary rocks, is located 150 km north-east of Nuuk, within the Archaean gneiss complex of West Greenland. Most of this gneiss complex consists of late Archaean rocks with a minor component of early Archaean age, including the oldest known supracrustal rocks on Earth. The Isua belt contains the best preserved of the oldest supracrustal components and is therefore of vital importance in providing information on the oldest known terrestrial environments and a prospective locality in which to search for the earliest traces of life on Earth (Mojzsis et al. 1996). The Isua Multidisciplinary Research Project (IMRP) aims to coordinate a reinvestigation of the geology of the Isua belt and adjacent tonalitic gneisses with a broad-based, diversely skilled, international research team. IMRP is supported by the Danish Natural Science Research Council, the Commission for Scientific Research in Greenland and the Minerals Office of the Greenland Government (from 1998, the Bureau of Minerals and Petroleum). The project began in 1997 with a pilot study of the north-east sector of the Isua belt to test the feasibility of reinvestigating the early Archaean geology on the basis of new mapping. Five weeks of field work were carried out by a core of four geologists (P.W.U.A, C.M.F., S.M., J.S.M.) augmented by visits of shorter duration by G. Arrhenius, A. Hofmann, V.R. McGregor, S. Mojzsis, R.K. O’Nions and H.K. Schønwandt. This report outlines the geological background to the current study and the results of the 1997 pilot project.

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