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Regional Radiometry 1975-1982 Surveys

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.

Simple

Date (Revision)
2022-01-01
Identifier
dk.geus: / radiometry
Presentation form
Digital map
Status
Completed
Point of contact
  Geological Survey of Denmark and Greenland (GEUS) - Björn H. Heincke
Oster Voldgade 10 , Copenhagen , 1350 K , Denmark
Custodian
  Geological Survey of Denmark and Greenland (GEUS) - Simun Olsen Dalsenni
Custodian
  Luleå University of Technology - Thorkild Maack Rasmussen
Maintenance and update frequency
As needed
GEMET - INSPIRE themes, version 1.0
  • Geology
Keywords
  • GGU
  • Radiometry
Continents, countries, sea regions of the world.
  • Greenland
Access constraints
Copyright
Use constraints
Copyright
Other constraints
No limitations on public access
Other constraints
Data is not confidential
Spatial representation type
Grid
Spatial representation type
Grid
Denominator
200000
Distance
100  m
Metadata language
English
Topic category
  • Geoscientific information
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Begin date
1975-01-01
End date
1983-01-01
Reference system identifier
EPSG / https://epsg.io/32624
Geometric object type
Complex
Distribution format
  • Web Service ( 1.0 )

Point of contact
  The Danish Geodata Agency -
Oster Voldgade 10 , Copenhagen , 1350 K , Denmark
OnLine resource
Interactive map ( WWW:LINK-1.0-http--link )

Interactive airborne radiometery maps on the Greenland Portal

OnLine resource
Web Service ( OGC:WMS )

grl_geophysic_radiometry

OnLine resource
Publication ( WWW:LINK-1.0-http--link )

Radiometry 75-76 (West Greenland)

OnLine resource
Publication ( WWW:LINK-1.0-http--link )

South Greenland Regional Uranium Exploration Project

OnLine resource
Web Service ( OGC:WMS-1.3.0-http-get-capabilities )

TC_all_utm24n

Hierarchy level
Dataset

Conformance result

Date (Publication)
2010-12-08
Explanation
This field has no significance
Pass
No
Statement

Due to the sparse data coverage with surveying along contour lines and the lack of GPS positioning, both the spatial resolution and the spatial accuracy is low. In addition, some of the data (1975/76 surveys) were originally stored on magnetic tapes, which were partly under bad physical conditions.

The company DRTS Ltd, St Pauls Cray, Kent, England, a private company specialized in the recovery of data from old tapes, was contracted from GEUS to transfer the data from the tapes and most - but not all - of the data were recovered. Details about the data recovery process and data quality evaluation of the 1975/76 are given in the GEUS report 2003-37 “Digital airborne radiometric data from the 1975 and 1976” and we recommend to contact Thorkild Maack Rasmussen (now Luleå University, formerly GEUS), who was involved in this process, for any further information about this process.

Only counts for four windows were collected (probably total count, K, eU, eTh) and spectral data are missing. This very much limits the options of reprocessing and more advanced processing techniques for noise removal and radon reduction in the uranium window are not possible.

The gamma-spectrometer had been calibrated at a pad facility at Risø, which enabled the conversion of recorded counts per second in the four channels to simulated concentrations of radioactive components in the surface of the overflown terrain and K is given in % and eU and eTh in ppm.

In summary, the datasets are not comparable with nowadays acquired radiometric airborne data, neither in their data quality nor in the uniformity and density of the data coverage. This means the main value of these data lie in the regional extent such that large areas of West Greenland and South Greenland can be qualitatively evaluated in terms of the natural radioactive isotopes.

File identifier
368ed153-74e2-4eec-9970-99e221654ae3 XML
Metadata language
English
Hierarchy level
Dataset
Date stamp
2023-06-23T14:22:50
Metadata standard name
ISO 19115:2003 / ISO 19139:2007
Point of contact
  Geological Survey of Denmark and Greenland (GEUS) -
Oster Voldgade 10 , Copenhagen , 1350 K , Denmark
 
 

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Keywords


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