Geology and Mineral Potential of South-East Greenland. Final report from the South-East Greenland Mineral Endownment task (SEGMENT)

South-East Greenland between 62°30’N and 66°30’N was before 2009 one of the most poorly known areas of Greenland. Following expeditions in the early 20st Century, geologists from British Universities mapped the area from the shore in the 1960s. The Greenland Geological Survey (GGU) joined these geological mapping expeditions in the late 1960s, early 1970s and early 1980s. Helicopter and fixed-wing aircraft support was first available in 1986 and 1987, where areas further inland could be mapped. These expeditions resulted in two 1:500 000 scale map sheets and continued geological research in collaboration with researchers from several universities. Regional geochemical or geophysical data sets were not compiled and in very poor resolution. Two efforts by universities and GGU were accomompained by only limited mineral exploration. Kryolitselskabet Øresund A/S and Nordisk Mineselskab A/S carried out helicopter supported prospecting of the area and at Kialineq (Kialeq) in 1963 and 1971, respectively. Graphitemineralisation north of Tasiilaq was discovered during GGU campaigns and were briefly mapped and studied byMineral Development International A/S in 1992 (Kalvig 1992). Nickel-PGE sulphide mineralisation in the Ammassalik Intrusive Complex (AIC) close to Tasiilaq areahas received most attention with a more detailed exploration program since 1996 by various companies (Lie 1997).

When the South-East Greenland Mineral ENdowment Task (SEGMENT) project was organized in late 2008 and early 2009 in collaboration between the Geological Survey of Denmark and Greenland (GEUS) and the Bureau of Minerals and Petroleum (BMP, now Ministry of Mineral Resources, MMR) the main aims were jointly formulated as:

• Compiling a regional stream sediment geochemical and till indicator mineral survey;
• Compiling a regional aeromagnetic survey of South-East Greenland;
• Conduct geological field investigations in order to characterise the main lithology and as the basis for geological research, including petrology, structural geology, geochemistry and geochronology;
• Evaluate economic geology and mineral potential through field investigations, using geological parameter in order to be able to predict possible mineralisation;
• Revise the existing 1:500 000 geological map of South-East Greenland; and
• Integrated data interpretation to describe and provide a geological model for the geological evolution of South-East Greenland and assess the mineral of potential of the region.

In this report, we summarize the data collected and the main research results that are based on intense field expeditions in the previous years aimed at reaching the main goals listed above. The report aims at providing an overview of all rock units and events encountered in the area covered by the SEGMENT project. Consequently, to gain the most of the report it is suggested that it is used in conjunction with the reviesed 1:500 000 scale map which is accessible and printable from on the ‘SEGMENT Data Package’ that is accessible on the memory-stick which is enclosed to this report (see also section ‘2 SEGMENT Data Package’).

This report represents the status at the time of writing, and numerousongoing joint research projects will continue to publish new data on the area between 62°N and 66°30’N. Not all researchers or institutes that have been involved in collaborative projects under the SEGMENT framework are represented in this report, but itshould be emphasized that without their contribution and scientific discussion, this project would not have been successful. The large-scale effort that was made during the SEGMENT project including costly field expeditions, thus, not only yields a return in the form of new data generated during the project, but also has a more sustainable aspect in continued research within joint research projects between mainly GEUS, MMR and various university partners based on the collected data.

During the SEGMENT project, the 1:500 000 scale maps have been continuously updated with corrections and new data. This report is organized chronologically starting with the Archaean and describes the main map units. It should, therefore, be read together with the updated map sheets. Brief chapters summarize our current understanding of the geological evolution, mainly during the Archaean and Palaeoproterozoic, where most of the study area was transformed into a stable shield with limited reactivation in the Mesoproterozoic and the Tertiary continental breakup in the north. The regional geochemical and geophysical data sets are briefly described, and the report ends with a description of mineralisation and mineralising processes. This report can only give a summary and brief overview of the data and research results, which are already published in GEUS reports and international peer-reviewed journals. We aimed at a comprehensive reference list so the interested reader is able to continue his or hers research in the relevant articles.