GAMMASPEKTROMETRI

Helicopter-borne magnetic, electro-magnetic and radiometric geophysical survey in Meråker, Trøndelag County

NGU-RAPPORT
2021.039
Publikasjonstype
Utgivelsesår
2022
ISSN
0800-3416
Prosjektnr
388900
Summary
As an addition to NGU’s general geophysical mapping in Trøndelag, NGU conducted a high-resolution airborne geophysical survey in Meråker area in Trøndelag County on request of Norra Metals. This report describes and documents the acquisition, processing and visualization of the acquired datasets and presents them in maps. The geophysical surveys consist of 1054 line-km data, covering an area of 219 km2 flown on July 21st, 2021.
The NGU modified Geotech Ltd. Hummingbird frequency domain electromagnetic system supplemented by an optically pumped Cesium magnetometer and the Radiation Solutions 1024 channels RSX-5 spectrometer mounted on a AS350-B3 helicopter was used for data acquisition.
Forfattere
Mrope, Frida Mathayo
Dumais, Marie-Andrée
Ofstad, Frode
Stampolidis, Alexandros
Nasuti, Aziz
Kristiansen, Tom
Tassis, Georgios
Kommune
MERÅKER
Fylke
TRØNDELAG
Tilgjengelig
NGU-biblioteket
Prosjekt
Flygeofysisk kartlegging av Norge

Helicopter-borne magnetic, electro-magnetic and radiometric geophysical survey in Bleikvasslia, Nordland County

NGU-RAPPORT
2021.036
Publikasjonstype
Utgivelsesår
2022
ISSN
0800-3416
Prosjektnr
388900
Summary
As an addition to NGU’s general geophysical mapping in Nordland, NGU conducted a high-resolution airborne geophysical survey in Bleikvasslia area in Nordland County on request of Norra Metals. This report describes and documents the acquisition, processing and visualization of the acquired datasets and presents them in maps. The geophysical surveys consist of 326.7 line-km data, covering an area of 59.3 km2 flown on August 21st, 2021.
The NGU modified Geotech Ltd. Hummingbird frequency domain electromagnetic system supplemented by an optically pumped Cesium magnetometer and the Radiation Solutions 1024 channels RSX-5 spectrometer mounted on a AS350-B3 helicopter was used for data acquisition.
Forfattere
Stampolidis, Alexandros
Dumais, Marie-Andrée
Ofstad, Frode
Mrope, Frida Mathayo
Nasuti, Aziz
Kommune
HEMNES
Fylke
NORDLAND
Tilgjengelig
NGU-biblioteket
Prosjekt
Flygeofysisk kartlegging av Norge

Helicopter-borne magnetic, electro-magnetic and radiometric geophysical survey in Evje and Hornnes and Iveland, Agder County

NGU-RAPPORT
2021.030
Publikasjonstype
Utgivelsesår
2021
ISSN
0800-3416
Prosjektnr
388900
Summary
As an addition to NGU’s general geophysical mapping in Agder, NGU conducted a high-resolution airborne geophysical survey in Evje & Hornnes and Iveland area in Agder county on request of Norse Minerals AS.
This report describes and documents the acquisition, processing and visualization of the acquired datasets and presents them in maps. The geophysical surveys consist of 301 line-km data, covering an area of 31.5 km2 flown on June 12th, 2021.
The NGU modified Geotech Ltd. Hummingbird frequency domain electromagnetic system supplemented by an optically pumped Cesium magnetometer and the Radiation Solutions 1024 channels RSX-5 spectrometer mounted on a AS350-B3 helicopter was used for data acquisition.
Forfattere
Mrope, Frida Mathayo
Dumais, Marie-Andrée
Ofstad, Frode
Baranwal, Vikas Chand
Tassis, Georgios
Kommune
EVJE OG HORNNES
IVELAND
Fylke
AGDER
Tilgjengelig
NGU-biblioteket
Prosjekt
Flygeofysisk kartlegging av Norge

Helicopter-borne magnetic, electro-magnetic and radiometric geophysical survey in Selbusjøen area, Trøndelag County

NGU-RAPPORT
2024.005
Publikasjonstype
Utgivelsesår
2024
ISSN
0800-3416
Prosjektnr
388900
Summary
NGU conducted an airborne geophysical survey in Selbusjøen area, in Klæbu, Trondheim, Malvik and Selbu municipalities in Trøndelag County, as part of NGU’s general airborne mapping program. The data acquisition was carried out from August 10th to September 9th, 2023.
This report describes and documents the acquisition, processing and visualization of the acquired datasets and presents them in maps. The geophysical survey consists of 2841 line-km data, covering an area of 591 km2, flown from the base at Vassfjellet ski centre. The last flight consisting of re-flown lines to improve the magnetic data was flown from the base in Okkenhaug near Levanger.
The NGU modified Geotech Ltd. Hummingbird frequency domain electromagnetic system supplemented by an optically pumped caesium magnetometer and the Radiation Solutions 1024 channels RSX-5 spectrometer mounted on a AS350-B3 helicopter were used for data acquisition. The data collected were processed at NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and levelled using Geosoft micro-levelling algorithm. Radiometric data were processed using standard procedures as recommended by International Atomic Energy Association (IAEA). Electromagnetic data were filtered and levelled using both automated and manual levelling procedures. Apparent resistivities were calculated from in-phase and quadrature data for three coplanar frequencies (880 Hz, 6.6 kHz and 34 kHz), and for two coaxial frequencies (980 Hz and 7 kHz) separately using a homogeneous half-space model. All data were gridded using cell size of 50x50 meters and presented as 40% transparent grids on top of topographic maps.
Forfattere
Dumais, Marie-Andrée
Ofstad, Frode
Kristiansen, Tom
Mrope, Frida Mathayo
Kommune
SELBU
KLÆBU
TRONDHEIM
MALVIK
Fylke
TRØNDELAG
Tilgjengelig
NGU-biblioteket

Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey in Forollhogna area, Innlandet and Trøndelag Counties

NGU-RAPPORT
2022.018
Publikasjonstype
Utgivelsesår
2023
ISSN
0800-3416
Prosjektnr
388900
Summary
NGU conducted an airborne geophysical survey in Forollhogna area, in Rennebu, Midtre
Gauldal and Holtålen municipalities in Trøndelag County, and Tynset, Tolga and Os
municipalities in Innlandet County, as part of NGU’s general airborne mapping program. The
data acquisition in Forollhogna area was carried out from June 23rd to July 20th, 2021.
This report describes and documents the acquisition, processing and visualization of the
acquired datasets and presents them in maps. The geophysical survey consists of 8214 linekm data, covering an area of 1609 km2, flown from the base near Orvos (Flight 1-38) and from
the base near Frigården (Flight 39).
The NGU modified Geotech Ltd. Hummingbird frequency domain EM system supplemented
by an optically pumped Cesium magnetometer and the Radiation Solutions 1024 channels
RSX-5 spectrometer mounted on a AS350-B3 helicopter were used for data acquisition.
The data collected were processed at NGU using Geosoft Oasis Montaj software. Raw total
magnetic field data were corrected for diurnal variation and leveled using Geosoft microlevelling algorithm. Radiometric data were processed using standard procedures as
recommended by International Atomic Energy Association (IAEA).
EM data were filtered and leveled using both automated and manual levelling procedures.
Apparent resistivity was calculated from in-phase and quadrature data for three coplanar
frequencies (880Hz, 6.6kHz and 34kHz), and for two coaxial frequencies (980Hz and 7kHz)
separately using a homogeneous half space model.
All data were gridded using cell size of 50x50 meters and presented as 40% transparent
grids with shaded relief on top of topographic maps.
Forfattere
Ofstad, Frode
Dumais, Marie-Andrée
Barnes, Pierre-Carl
Kristiansen, Tom
Mrope, Frida Mthayo
Kommune
OS
MIDTRE GAULDAL
HOLTÅLEN
TOLGA
RENNEBU
Fylke
INNLANDET
TRØNDELAG
Tilgjengelig
NGU-biblioteket
Prosjekt
MINN - Helikoptermålinger

Borehole logging in Smøla and Bømlo

NGU-RAPPORT
2021.005
Publikasjonstype
Utgivelsesår
2021
ISSN
0800-3416
Prosjektnr
380200
Summary
AS a part of the Base 2 project NGU has performed geophysical borehole logging in four boreholes at Smøla, Møre and Romsdal county and three at Bømlo, Vestland county. The purpose of the drilling and logging was to study onshore deep weathered basement rocks. Such rocks can be a potential oil reservoir offshore, on the continental shelf.
The logged parameters were resistivity, porosity, seismic velocity, water conductivity, total gamma radiation, spectral gamma, magnetic susceptibility, Induced Polarisation, and Self Potential. All boreholes were logged using acoustic and optical televiewer. Flow measurements and pumping were performed. Lugeon test were done by the drilling company.
The results show heavily fractured rock in all boreholes. Especially in Bh4 at Smøla the resistivity was very low. Combined with low p-wave velocity and fracturing it can be interpreted as weathered and altered rock. IP anomalies may indicate clay.
The Lugeon tests showed quite low values and correlates well with the fracture frequency. From the Lugeon numbers the hydraulic conductivity and permeability are calculated. Calculated apparent porosity from the resistivity log, using Archi's law, is in the same range as laboratory porosity measurements on cores performed by NTNU. Most of the porosity values are in the range of 1 – 4 %.
Flow measurements showed no vertical flow in the boreholes and no in/out flow from fractures. Pumping indicated very low water capacity in all wells except Bh3, Bømlo. Near surface water just below the casing flowed into the borehole.
Bh2 at Bømlo was stuck at 27 m depth. Reopening of the borehole failed, and masses (sand, clay) flowed into the borehole and blocked it.
Forfattere
Elvebakk, Harald
Gellein, Jomar
Larsen, Bjørn Eskil
Kommune
SMØLA
BØMLO
Fylke
MØRE OG ROMSDAL
VESTLAND
Tilgjengelig
NGU-biblioteket

Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey in Røros area, Trøndelag county

NGU-RAPPORT
2021.024
Publikasjonstype
Utgivelsesår
2023
ISSN
0800-3416
Prosjektnr
388900
Summary
NGU conducted an airborne geophysical survey in Røros, Trøndelag county as part of
NGU’s general airborne mapping program in 2020.
This report describes and documents the acquisition, processing and visualization of the
acquired datasets and presents them in maps. The geophysical surveys consist of 2584 linekm data, covering an area of 523 km2 flown between June 15th to June 22nd, 2020.
The NGU modified Geotech Ltd. Hummingbird frequency domain EM system supplemented
by an optically pumped Cesium magnetometer and the Radiation Solutions 1024 channels
RSX-5 spectrometer mounted on a AS350-B3 helicopter was used for data acquisition.
The survey was flown with 200 meters line spacing, azimuth 90o
. Average speed was
95 km/h, and average height clearance of the EM bird was 47 m and 77 m for the
spectrometer.
Collected data were processed at NGU using Geosoft Oasis Montaj software. Raw total
magnetic field data were corrected for diurnal variation and levelled using standard levelling
algorithm. Radiometric data were processed using standard procedures recommended by the
International Atomic Energy Association (IAEA).
EM data were filtered and levelled using both automated and manual levelling procedures.
Apparent resistivity was calculated from in-phase and quadrature data for three coplanar
frequencies (880 Hz, 6.6 kHz and 34 kHz), and for two coaxial frequencies (980 Hz and 7 kHz)
separately using a homogeneous half space starting model of 1000 ohm-m.
All data were gridded using cell size of 50x50 meters. Magnetic and radiometric data is
presented as 40% transparent grids with shaded relief on top of topographic maps. EM data is
presented as 30% transparent grids on top of topographic maps.
Forfattere
Mrope, Frida Mathayo
Dumais, Marie-Andrée
Baranwal, Vikas Chand
Ofstad, Frode
Tassis, Georgios
Kommune
RØROS
Fylke
TRØNDELAG
Tilgjengelig
NGU-biblioteket

Geologisk kartlegging og økonomisk vurdering av bergarter og mineraler.

NGU-RAPPORT
1588/2
Publikasjonstype
Utgivelsesår
1978
ISSN
0800-3416
Summary
Undersøkelser er blitt utført på følgende kartblad i serie M 711 med hovedvekt på området vest for Namsen: Namsskogan 1824 I, Skorovatn 1824 II, Harran 1824 III, Kongsmoen 1824 IV, Majaklumpen 1825 II og Majavatn 1925 III (1:50 000). Den geologiske kartlegging har ført til en del korreksjoner på kartblad Namsskogan 1824 I (utført i 1977), videre er deler av kartblad Majaklumpen 1825 II blitt kartlagt. Følgende er dessuten blitt utført: Gammaspektrometri av bergartenes kaliuminnhold, tungmineralvasking (scheelitt). Behandling av innsamlede data og prøver: EDB-beregninger av kaliuminnholdet fra utført måledata, kjemiske og spektrografiske analyser av prøver fra tungmineralvasking og bergarter, mikroskopering av tynnslip av bergarter og statistikk av måledata (kalium) og analyser (tungmineraler).
Forfattere
Nissen, August L.
Kommune
NAMSSKOGAN
Fylke
TRØNDELAG
Tilgjengelig
NGU-biblioteket

Måling av naturlig radioaktiv stråling fra berggrunnen, Gran kommune, Oppland.

NGU-RAPPORT
88.033
Publikasjonstype
Utgivelsesår
1988
ISSN
0800-3416
Summary
Rapporten gir generell informasjon om naturlig radioaktiv stråling og hvordan denne måles. Videre gir rapporten en forenklet informasjon om radon i bomiljø. Det praktiske opplegget for NGUs målinger av naturlig gammastråling langs vei og til hvilken tid målingene i kommunen er gjort. Tolkningskart over naturlig stråling innenfor kommunen bygger på målingene og berggrunns- geologiske kart. En vurdering av eventuelle tiltak er gjort.
Forfattere
Lindahl, I.
Iversen, B.
Kommune
GRAN
Fylke
INNLANDET
Tilgjengelig
NGU-biblioteket

Måling av naturlig radioaktiv stråling fra berggrunnen, Østre Toten Kommune, Oppland.

NGU-RAPPORT
88.032
Publikasjonstype
Utgivelsesår
1988
ISSN
0800-3416
Summary
Rapporten gir generell informasjon om naturlig radioaktiv stråling og hvordan denne måles. Videre gir rapporten en forenklet informasjon om radon i bomiljø. Det praktiske opplegget for NGUs målinger av naturlig gammastråling langs vei og til hvilken tid målingene i kommunen er gjort. Tolkningskart over naturlig stråling innenfor kommunen bygger på målingene og berggrunns- geologiske kart. En vurdering av eventuelle tiltak er gjort.
Forfattere
Lindahl, I.
Iversen, B
Kommune
ØSTRE TOTEN
Fylke
INNLANDET
Tilgjengelig
NGU-biblioteket