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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.
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The dataset contains outlines of archived historical unpublished geological maps and sections of Greenland mostly created by GGU and GEUS but also some other institutes from 1916 onwards at various scales.
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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.
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Intrusions and magmatic complexes are central, when it comes to an assessment of the economic geological potential of a region. There are many of these in Greenland, and only a few of them have been examined in detail for their economic potential. In Nielsen (2002), tertiary intrusions and complexes in East Greenland were described, and later on information on intrusions and magmatic complexes in all of Greenland, were modelled based on the same methodology. The information has been compiled by GEUS geologists.
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The digital terrain model of Greenland is constructed on the basis of GEUS's topographic datasets from the official geological maps of Greenland in scale ratio 1:100.000 and 1:500.000. The DEM is created using an interpolation method called Topo to Raster function in ArcGIS Desktop which is primarily supported by contour lines, coastlines and elevation points. The creation of the DEM was divided into in sub-areas based on the map sheet frames from the geological map of Greenland in 1:500.000 scale and assembled as a raster mosaic. The DEM was created with the spatial coordinate reference system WGS 1984 / UTM Zone 24N Complex with a resolution of a 100x100 meter grid. Based on the final DEM, a hillshade efect of the terrain has been constructed.
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Greenland mineral assessment workshops have been held on Sedimentary-hosted Copper, type: redbed-, revett- and reduced-facies type in 2009, Various Rare Earth Elements deposit types in 2010 (this workshop was not carried out according to the 'three-part quantitative assessment' method), Sedimentary-hosted zinc SEDEX- and MVT-type in 2011, Magmatic nickel; komatiite-hosted, contact- and conduit-type in 2012 and Vein- and skarn type Tungsten in 2013 and Orogenic gold type in 2014. Most of the workshops, besides the one on rare earth elements, have been following the processes and methodologies used in the 'three-part quantitative assessment' method of the U.S. Geological Survey described by Singer (1993). The method does not define deposits or provide mineral resource or reserve estimates according to industrial or international recognised certified standards. The objective is to produce a probabilistic estimate of unknown/undiscovered deposits and corresponding probabilistic estimates of the total amount of metals down to one kilometre depth. The estimates do not take into account economic, technical, social or environmental factors. In the 'three-part quantitative assessment' method, an expert panel reviewed and discussed all available knowledge and data for a specific region (Tract) to assess the possibility of finding new undiscovered deposits within this Tract. The expert panels consisted of geologists from universities, research institutions, Surveys as well as private exploration and mining companies. The experts have either expertise in/worked with the deposit type in focus, with the regional and/or local geology relevant for the tracts being assessed or have expertise from exploration/mining projects for the deposit type in focus elsewhere in the world. One or two international top-experts on the mineral deposit type in focus for the different workshops have also participated in the workshop. After reviewing the available knowledge and data the members of the panel made their individual estimates (bids) of the number of undiscovered deposits they believed could be found under the best circumstances in a tract. The bids are based on the characteristics derived from descriptive mineral deposit models and a number of key-literature on the mineralisation type. In several of the workshops, critical elements have also been considered in the mineralising system (e.g. McCuaig & Hronsky 2014) associated with the deposit type in focus, when carrying out the bids. A panel discussion of the bids led to a consensus bid, which was used as input to a statistical Monte Carlo simulation. Based on established grade-/tonnage models of e.g. known tungsten deposits worldwide, this simulation can provide a prediction on how much undiscovered metals could be found within a Tract. The 'Tracts' are spatial polygons that define a certain area that was found to be permissive for the concerned mineral deposit type and which constitutes the same level of geology, knowledge and data coverage. Tracts are named with a unique name, tract area is given in square kilometre and consensus bids from team under N90, N50, N10, N05 and N01 headings of undiscovered metals deposits at different confidence levels. The statistics from the Monte Carlo simulation is shown under the headings Numbers of unknown deposits and Deposit density.
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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.
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Samples of surface material, i.e. stream sediment, soil, and scree have been collected over large parts of Greenland from 1974 onwards mainly as part of mineral exploration programmes and more broadly for geochemical mapping by means of stream sediment (Steenfelt 1999, 2001). Following various sample preparation procedures, like drying and screening, making concentrates of heavy minerals from stream sediment or soil, certain fractions of the samples have been chemically analysed at diverse laboratories where a range of analytical methods were applied as they became available over the years. The present dataset contains the analytical data from stream sediment as they were received from the laboratories together with administrative data, including sample location and grain-size fraction analysed. Many samples have been analysed at more than one laboratory and by more than one method and the analytical data for each sample and grain size fraction are listed lab by lab and method by method in the same row. The majority of the samples were collected and analysed before year 2000. More recent data from South-East and North Greenland have been added (Kolb et al 2016).
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Ujarassiorit is a mineral hunt competition open to residents of Greenland. Participants can submit rock samples from Greenland to the Ministry of Minerals Ressources (MMR) for evaluation and may be selected for a prize.
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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).
Geus Geonetworks metadata catalogue