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.

Protected areas in Greenland. The data are converted from the WFS that the ministery of mineral resources (MMR) in Greenland provides. Links are provided in the online resources.

The regional aeromagnetic datasets were acquired from the Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, Germany, in four field campaigns along the coastal regions of Northeast Greenland from 1993-1996. The line spacing ranges both in inline and crossline direction from 10-40 km and the levels range up to 3700 m. Presented maps are based on data reprocessed by GEUS.

All active exploitation licences. The data are converted from the WFS that th ministery of mineral resources (MMR) in Greenland provides. Links are provided in the online resources

This view presents data from stream sediment geochemical mapping of West and South Greenland (Steenfelt, 2001a). Stream sediment samples were collected from 1979 to 1998 with as even coverage as possible from low-order streams and with a sampling density of mostly around 1 sample per 30 km2 but up to 1 sample per 5 km2 in parts of South Greenland. The 0.1 mm grain size fractions of 500-g samples were analysed for major and trace elements by two or three methods. After careful quality control, selection of the most reliable analytical data and elimination of analytical bias (calibration), the final consistent dataset, named batch 2005, contains data from 7122 samples analysed for up to 43 elements (see Steenfelt 1999, 2001b for details on data selection and calibration). In batch 2005, values below lower detection limit are indicated by the digit 0. Sample location Before 1997, sample sites were originally marked on topographic maps at the scale 1:100,000 and their positions were later digitised and later again corrected, when a new topographic reference was introduced around year 2000. From 1997 onwards, GPS was used to determine sample positions.

Uniform aerial photographic coverage of Greenland was achieved in 1978-1987 at 1: 150 000 scale by Mark Hurd Aerial Surveys, Inc., Minneapolis, Minnesota, U.S.A., for the Danish Geodetic Institute [Weidick, 1995]. The photography is now administered by the Danish Geodata Agency, see also http://eng.gst.dk/maps-topography/greenland/aerial-photos-of-greenland. The camera used for these black and white photographs was a Wild RC 10 with a super wide angle lens (focal length = 88 cm). The airplane used by Mark Hurd was a Gates Lear Jet 25C. By setting the flying height to app. 14 km the image scale of 1:150 000 was achieved [Bengtsson & Jørgensen, 1980]. In an attempt to avoid blind areas, caused by the precipitous mountainsides in combination with the use of a super wide angle lens, the photographs were taken with a length-lap of 80%, and a side-lap of 40%. In the subsequent use of the photography (for aerotriangulation, mapping and scanning) generally only every other image were used (as you will see from the photo number shown on this web-page). The photo center coordinates are from the aerotriangulation by the Danish Geodata Agency. Please contact GST for the high resolution photos.

The AEM Greenland 19941998 are detailed surveys with combined electromagnetic and magnetic measurements that were carried out within a collaboration between GEUS/GGU and the Greenland Government in six selected areas of expected high mineral potential in Greenland. In total, 75 000 line km covering an area of 23 000 km² were measured in the project. Line spacing was 200 400 m (inline direction) and flight altitudes were typically around 120 m. With exception of one survey the collected electromagnetic data were time-domain data (GEOTEM system).

The development of this new magnetic compilation from Greenland was initiated by the working group of Satellite- and Aerogeophysics at the Christian-Albrechts-University (CAU) in Kiel, Germany, and GEUS as part of the ESA project GOCE+Greenland in 2021. The total magnetic intensity anomaly map from South Greenland is the first part of a compilation that will be stepwise extended to cover whole Greenland including the Inland Ice and the adjacent shelf regions. It is built out of all accessible modern regional aeromagnetic surveys from Greenland but also uses older datasets without GPS positioning in areas where modern data are lacking. Magnetic data are currently taken from the surveys of the AEROMAG and AEM projects (Rasmussen et al., 2013; Riisager & Rasmussen, 2014), GICAS project (e.g., Thorning et al., 1988), EASTMAR project (Larsen & Thorning, 1980), ICEBRIDGE project (see https://pgg.ldeo.columbia.edu/data/operation-icebridge ), GAP91/92 project (Brozena, 1992) and from offshore datasets acquired by the TGS-NOPEC TGS GEOPHYSICAL COMPANY. Since long wavelength components in aeromagnetic data are often considered as unreliable, they are replaced by the ones from the LCS-1 satellite model (Gaussian coefficients with degrees n = 13 – 133; Olsen er al., 2017). The magnetic map is generated by a methodology that combines equivalent source modelling and a spherical harmonic expansion. The datapoints at their actual measuring locations are used as data input and magnetic dipoles are employed as equivalent sources that are arranged in three uniform grids with different source spacing and depths (coarsest spacing: 10 x 10 km; finest spacing: 0.7 x 0.7 km). The presented total magnetic intensity map is simulated from the dipole responses at a constant height of 2000 m asl and with a grid spacing of 700 x 700 m. Regularizations in the inversion for the different equivalent source grids are chosen such that the resulting resolution is flexible and adapted to the largely varying magnetic data coverage in Greenland. A publication is in preparation that will provide more details about the data, methodology, implementation, and map quality. How to cite: Björn H. Heincke, Wolfgang Szwilius, Judith Freienstein and Jörg Ebbing (2023). A new magnetic compilation from Greenland built by a combination of equivalent source modeling and spherical harmonic expansion. Greenland Portal, https://maps.greenmin.gl/geusmap/?mapname=greenland_portal&lang=en References: Brozena, J.M. (1992). The Greenland Aerogeophysics Project: Airborne Gravity, Topographic and Magnetic Mapping of an Entire Continent. In: Colombo, O.L. (eds) From Mars to Greenland: Charting Gravity with Space and Airborne Instruments. International Association of Geodesy Symposia, vol 110. Springer, New York, NY. https://doi.org/10.1007/978-1-4613-9255-2_19 Larsen, H., & Thorning, L. (1980). Project EASTMAR: acquisition of high sensitivity aeromagnetic data off East Greenland. Rapport Grønlands Geologiske Undersøgelse, 100, 91–94. https://doi.org/10.34194/rapggu.v100.7707 Olsen, N., Ravat, D., Finlay, C., & Kother, L. K. (2017). LCS-1: A high-resolution global model of the lithospheric magnetic field derived from CHAMP and Swarm satellite observations. Geophysical Journal International, 211(3), 1461–1477. https://doi.org/10.1093/gji/ggx381 Rasmussen, T. M., Thorning, L., Riisager, P. & Tukiainen, T. (2013). Airborne geophysical data from Greenland. Geology and Ore – Exploration and Mining in Greenland, No. 22 – February 2013, 12 pages. https://eng.geus.dk/media/13207/go22.pdf Riisager, P., & Rasmussen, T. M. (2014). Aeromagnetic survey in south-eastern Greenland: project Aeromag 2013. GEUS Bulletin, 31, 63–66. https://doi.org/10.34194/geusb.v31.4662 Thorning, L., Bower, M., Hardwick, C., & Hood, P. (1988). Greenland ice cap aeromagnetic survey 1987: completion of the survey over the southern end of the Greenland ice cap. Rapport Grønlands Geologiske Undersøgelse, 140, 70–72. https://doi.org/10.34194/rapggu.v140.8039

In the present database there are 1269 unique samples. Soil samples have been collected in areas without river beds. Preferably stream samples have been collected, but areas where temporarily no stream beds are present, soil samples have been collected as an alternative for geochemical mapping purpose. Five samples in this package are originally from the report Compilation of data sets for a geochemical Atlas (Steenfelt, 1999). These samples have been analysed by "UNKNOWN" methods at "UNKNOWN" laboratories. In fact these samples have been calibrated and corrected for analytical bias, see Steenfelt 1999, for further information.

The Samba database among other things contains information about deep wells in the Danish sector, acquired according to the Danish Act on the Use of the Subsoil. That is: exploration, appraisal, delimitation and production wells related to oil/gas. Also wells with other purposes such as: geothermal energy, gas storage, salt production and scientific research. The data sets contains technical, administrative and geological information about the well and about the geophysical measurements undertaken in the well (well logs and reports). Data are submitted by the company to whom the permission has been granted. The database is updated on an ongoing basis.