The Raw stream sediment samples dataset is data as they have been delivered from the laboratories, i.e. values below detection limit often spelled as negative but zero may also apply. The data are not controlled by a geologist. In addition, they may not have been reported.

The regional-scale gamma spectrometry data are associated with two collaboration projects involving the Geological Survey of Greenland (GGU) and the Danish Atomic Energy Commission’s Research Establishment. The projects' objectives were to outline areas with an elevated uranium potential in two regions of Greenland: The airborne radiometric surveys in southern and central West Greenland in 1975/76 and the SYDURAN project in South Greenland in 1979-1982. To acquire the data, four-channel gamma ray spectrometers were mounted upon an aircraft (1975/76 surveys) and a helicopter (SYDURAN project). The vehicles flew along shoreline and valley contour lines at low average terrain clearances of 100 and 50 m respectively. The data were recorded without GPS systems, and so positioning was estimated when known landmarks were passed. This means that the dataset is sparse and inhomogeneous, and the spatial accuracy remains low. The gamma-spectrometer had been calibrated at a pad facility at Risø, which enabled the conversion of recorded counts per second into simulated concentrations of radioactive components in the surface of the overflown terrain. Large parts of the data (surveys from 1975/76) were originally stored on magnetic tapes and data were transferred to datafiles in 2003 to make them digital accessible. Most data were retrieved and are now available as ASCII files.

Exploration companies are obliged to report their activities to the Ministry of Minerals and Resources (MMR). Now reports are delivered in digital format, but were previously delivered in paper, to the Geological Survey of Denmark and Greenland (GEUS). They are scanned and released reports are available under Reports. Digital restoration The data that the reports hold is thus available, but stored as images in scanned pdf?s. The geochemical data of 4 reports (Allen & Harris, 1980; Coppard et al., 1992; Harris et al., 1992 and Pearson & Joudrie, 1995) have been digitized. I.e. the reports have be optically characterised and the sample locations georeferenced. The matching of the sample locations and geochemically referenced samples does not always match. Meaning that a sample that has coordinate may not have geochemical results, and a sample with geochemical measurements might not have coordinate. The reporting of the analytical facilities and precision is sparse. Detection limits, analytical uncertainty and reliability are generally not reported. Analytical methods and analysed grain fractions of sediment samples also not reported. When all these issues have been listed, it should be noted that errors may occur. From the digital restoration of scanned paper to optically characterisation of the scanned text and numbers errors may be introduced. The user is cautioned to these issues. Upload to data base To make the data available on the web, upload to GEUS sample data base is required. To fit into the sample data base, some adjustments had to be made. Sample names modified, collector created etc., resulting in modified sample names, relative to the ones used in the reports. The reports from which the samples occur in are not mentioned in the data base. Hence the four reports and links to them are listed below:

The geophysical data available on the Greenland Mineral Resources Portal are both released company data and data acquired based on public funding (AEM and Aeromag surveys). The AEM Greenland 1994-1998 project, encompassed high resolution detailed multi-parameter surveys (electromagnetic, magnetic and partly radiometric) in the years 1994, 1995, 1996, 1997, and 1998 survey 1 and survey 2 producing a total of 75 000 line kilometres. The Aeromag projects, encompassed high resolution magnetic surveys conducted in 1992, 1995, 1996, 1997, 1998, 1999, 2001, 2012 and 2013 producing a total of more than 550 000 line kilometres. The projects were financed by the governments of Greenland and Denmark. More detailed information on the available geophysical date is given in Geology and Ore No. 22.

This map is the first national map showing the depth in meters to the uppermost redox interface in sediments of Quaternary age. The redox interface indicates the transition from the oxidized to the reduced geochemical environment in sediments. The redox interface was identified according to the colors of the sediments in 11,999 wells and is shown for 1x1 km grid-cells. For grid-cells with multiple site information, the depth to the redox interface is indicated by an average value. For grid-cells without any field information, the depth of the redox interface was established based on information about 1) geological setting, 2) morphology, 3) depths to redox boundaries at nearby field sites, 4) GEUS surface geology map, 5) topography, and 6) the pre-quaternary surface. The method for this first national redox-map and the data used is described in GEUS report no. 93 (2006) entitled Beregning af nitrat-reduktionsfaktorer for zonen mellem rodzonen og frem til vandløbet. Data og metode for 1.generationskortet (in Danish). The Redox map is also described in Vand og Jord (2011) 18: 37-39 (in Danish).

The digital geological map shows the surface geology. The map is a result of the systematic geological mapping of Denmark. The map is digitized from maps originating from fieldwork, where sediment samples are collected at 1m depth using a hand auger with a sample spacing of 100 - 200 m. This version 6 from 2021 classifies 91 % of Denmark's area. The map is supplemented in an ongoing process. The legend shows 82 different sediment types. The map is published in GEUS report 2021/68, where further information is available in Danish.

The dataset contains the General Batymetric Chart of the Oceans (GEBCO) based on GEBCO_2019 Grid from 2019. The dataset has been projected to WGS 84 / IBCAO Polar Stereographic projection (EPSG:3996) and extends down to 50° latitude. The complete data set provides global coverage, spanning 89° 59' 52.5''N, 179° 59' 52.5''W to 89°: 59' 52.5''S, 179° 59' 52.5''E on a 15 arc-second grid. It consists of 43200 rows x 86400 columns, giving 3,732,480,000 data points. The data values are pixel-centre registered i.e. they refer to elevations at the centre of grid cells. The GEBCO_2019 Grid is a continuous, global terrain model for ocean and land with a spatial resolution of 15 arc seconds. The grid uses as a ‘base’ Version 1 of the SRTM15+ data set (Olson et al, 2014). This data set is a fusion of land topography with measured and estimated seafloor topography. It is largely based on version 11 of SRTM30+ (Becker et al, 2009; Sandwell et al, 2014), augmented with the gridded bathymetric data sets developed by the four Seabed 2030 Regional Centers. The published data were recalculated on a cell-registered grid for use by GEBCO. The GEBCO_2019 Grid includes data sets from a number of international and national data repositories and regional mapping initiatives.

Zircon age data as gathered from literature and GEUS samples

A series of Aster band ratios highlighting mineral distributions. Band ratio color composite images to distinguish variability of lithology in the area. Preprocessing of the Aster scenes encompasses atmospheric, radiometric and topographic corrections before masking non-outcrop pixels and generating the final mosaic. The calibrated radiance data is converted to apparent surface reflectance using a radiative transfer program, Atmospheric and Topographic Correction (ATCOR-3), in rugged terrain mode. The ATCOR rugged terrain mode utilizes a surface elevation model to adjust illumination levels. Calibration and adjusting the apparent surface reflectance values from the ATCOR-3 processing was not feasible due to lack of ground-based reflectance measurements.

Cross sections and map profiles from different geological maps and publications.