Sökning: "Exploration Geophysics"

Visar resultat 16 - 20 av 27 avhandlingar innehållade orden Exploration Geophysics.

1. 16. Geophysical investigation for 3D geological modelling and ore exploration in the Skellefte mining district

   Författare :Saman Tavakoli; Thorkild Rasmussen; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tillämpad geofysik; Applied Geophysics;

   Sammanfattning : The Skellefte mining district, northern Sweden, is regarded as one of the country’s richest mineral districts. Most of the outcropping deposits in this district or those deposits which are located at shallow depths (≤ 300 m) are likely to have already been discovered, which motivated the Swedish mining companies to expand their explorations at greater depths (e. LÄS MER

3. 17. Reflection seismic investigation in the Skellefte ore district : A basis for 3D/4D geological modeling

   Författare :Mahdieh Dehghannejad; Christopher Juhlin; Ari Tryggvason; Charles Hurich; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Skellefte district; reflection seismic; mineral exploration; 3D 4D modeling; mineralization; faults and shear zones; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Sammanfattning : The Skellefte ore district in northern Sweden is a Palaeoproterozoic volcanic arc and one of the most important ones hosting volcanogenic massive sulfide (VMS) deposits, producing mainly base metals and orogenic gold deposits. Due to high metal prices and increased difficulties in finding shallow deposits, the exploration for and exploitation of mineral resources is quickly being moved to greater depths. LÄS MER

4. 18. Three-dimensional forward modelling and inversion of controlled-source electromagnetic data using the edge-based finite-element method

   Författare :Paula Rulff; Thomas Kalscheuer; Michael Becken; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied geophysics; Controlled-source electromagnetics; Numerical modelling; Finite-element method; Geophysical inversion; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Sammanfattning : Electromagnetic geophysical methods are applied to investigate anomalous subsurface structures exhibiting contrasts in electrical resistivity, as for example in mineral exploration or geothermal areas. When evaluating electromagnetic data, one big challenge is to account for full three-dimensional measurement setups and subsurface scenarios. LÄS MER

5. 19. Mapping and characterisation of Swedish bedrock by DC resistivity and transient-field electromagnetic measurement

   Författare :Hans Thunehed; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tillämpad geofysik; Applied Geophysics;

   Sammanfattning : DC electrical and electromagnetic methods have been used for a long time to detect and characterise fracture zones in site investigations and other engineering projects. However, the methods have not been used very much in basic geological mapping of crystalline rock on a regional to semi-regional scale. LÄS MER

7. 20. New Techniques for Estimation of Source Parameters : Applications to Airborne Gravity and Pseudo-Gravity Gradient Tensors

   Författare :Majid Beiki; Laust Pedersen; Mehrdad Bastani; Mark Pilkington; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Gravity gradient tensor; pseudo-gravity; magnetic field; eigenvector analysis; least squares algorithm; strike direction; source parameter estimation; analytic signal; Euler deconvolution; joint inversion; infinite dike model; geological contact model; Solid earth physics; Fasta jordens fysik; Geophysics with specialization in Solid Earth Physics; Geofysik med inriktning mot fasta jordens fysik;

   Sammanfattning : Gravity gradient tensor (GGT) data contains the second derivatives of the Earth’s gravitational potential in three orthogonal directions. GGT data can be measured either using land, airborne, marine or space platforms. LÄS MER