Karrat 97: reconnaissance mineral exploration in central West Greenland

Abstract

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example:
 Steenfelt, A., Thomassen, B., Lind, M., & Kyed, J. (1998). Karrat 97: reconnaissance mineral exploration in central West Greenland. Geology of Greenland Survey Bulletin, 180, 73-80. https://doi.org/10.34194/ggub.v180.5089
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 The Karrat 97 project aims at the acquisition of geochemical data from drainage samples and information on mineralisation within a 10 000 km2 area, which stretches from Uummannaq northwards to Prøven (i.e. from 70°30′ to 72°30′ N; Fig. 1). The project area comprises a major Palaeoproterozoic supracrustal unit, the Karrat Group, from which the project takes its name, and which hosts the abandoned Black Angel lead-zinc mine. It is a joint project between the Geological Survey of Denmark and Greenland (GEUS) and the Bureau of Minerals and Petroleum (BMP), Government of Greenland, and wholly funded by the latter. The goal of the project is to win back the interest of the mining industry to the area. The eastern part of the project area is difficult of access due to alpine topography with peaks up to 2300 m, abundant glaciers, and steep-sided, often ice-filled fjords. A somewhat more gentle topography prevails in the western parts of the area. The whole area is underlain by permafrost. Field work was carried out during seven weeks in July–August 1997 by a team of four geologists and four local prospectors. Job-training of the prospectors was an integral purpose of the project, and the manning of the teams was periodically changed so that all four prospectors were introduced to the different topographical and geological terrains in the area as well as to the methods of operation. A chartered 68 foot, 77 tons vessel – M/S Nukik – served as mobile base with accommodation and meals on board; a MD 500 E helicopter with crew chartered through Grønlandsfly A/S participated for one month. The work was carried out from five anchorages, with the helicopter stationed on the adjacent coast. The weather was relatively unstable in the field period, but only five days of work were lost due to bad weather. The field work comprised regional-scale systematic drainage sampling, and detailed mineral exploration at selected sites. The sampling of stream sediment and stream water supplements the geochemical mapping programme of Greenland undertaken jointly by GEUS and BMP (Steenfelt 1993, 1994), the aim of which is to provide systematic, quality controlled geochemical data. The data are used together with geological and geophysical information in the evaluation of the potential for economic mineral resources. Samples were collected by two teams, transported by helicopter or small boats. All ice-free, near-coastal localities were sampled by the boat team, whereas all other localities were sampled by the helicopter team. The results of this work have been reported on by Steenfelt et al. (1998). The detailed mineral exploration was follow-up work on previously outlined indications and anomalies. It was carried out by two teams on daily trips by rubber dinghy or helicopter, or by foot traverses from field camps. This part of the project has been reported on by Thomassen & Lind (1998).

Reconstruction of Holocene oceanographic conditions in eastern Baffin Bay

“…High counts of this element therefore indicate a minimal contribution of terrestrial-sourced material to the bulk sediment (Calvert and Pedersen, 1993;Rothwell and Croudace, 2015). K and Rb are both typical for environments with terrestrial influence (Saito, 1998;Steenfelt, 2001;Steenfelt at al., 1998). The Ca/Ti and Ca/Sr ratios can be used as indicators of the marine biogenic origin of Ca (Bahr et al, 2005;Richter et al, 2005).…”

A high-resolution elemental record of post-glacial lithic sedimentation in Upernavik Trough, western Greenland: History of ice-sheet dynamics and ocean circulation changes over the last 9100 years

“…The bedrock of western Greenland varies in age from Archaean to Paleogene (Escher and Pulvertaft, 1995). According to Steenfelt et al (1998) and the 1:250 000 geological map of Henriksen et al (2000), the exposed bedrock belongs to 4 main geological formations (Fig. 1):…”

“…The northern and southern Karrat provinces can be differentiated by peak Zn concentrations in the later region drained by Rink Isbrae (Fig. 1 and Steenfelt et al, 1998).…”

The deglaciation of Upernavik trough, West Greenland, and its Holocene sediment infill: processes and provenance

“…In order to ensure comparability, only elements that are present in the XRF-scanning data from our sediment cores are considered for the geochemical characterization of the potential onshore source areas. Based on previously published compositional data of onshore sediments/rocks (Carter et al 1979;Nelson 1989;Holm et al 1993;Steenfelt et al 1998;Steenfelt 2001;Larsen & Pedersen 2009;Larsen et al 2016), the Nuussuaq basin volcanics are characterized by relatively low SiO 2 contents and highest Fe 2 O 3 and TiO 2 contents, as well as lowest K 2 O and Zr concentrations. Accordingly, the Al/Ti ratio is lowest of all provinces, while the Fe/K is the highest of all provinces.…”

“…Samples marked with an asterisk were previously published by Saini et al (2020;GeoB19927-3) and Slabon et al (2016;GeoB19920-1) Statistical analyses Provenance analysis. -In order to link the sediment core data to the onshore geology, we followed and extended the approach of Giraudeau et al (2020) in that we used the stream-sediment data compiled by Steenfelt et al (1998) and Steenfelt (1999Steenfelt ( , 2001 but also added data from whole-rock analyses available via the PetDB/EarthChem portal (PetDB: https://search. earthchem.org/; EarthChem: http://portal.earthchem.…”