GTK Geophysics
Deep electromagnetic sounding, Western Greenland, 2013
Heikki Vanhala, 2014
Geophysicists in GTK
Northern Finland
Office
kokkola
Rovaniemi
Rovaniemi
Espoo
Kuopio
&
KP
(3)
Western Finland
Office
Eastern Finland
Office
Kokkola
Kuopio (6)
(4)
Academic degree:
• M.Sc.
25
• Dr.
6
• Total
31
*end of 2014
Outokumpu
Loppi
Southern Finland
Office
Espoo
(20)
Most geophysicists work with mineral resources
- In projects related to:
LAND USE &
CONSTRUCTIONS
Constructions
Eco-efficient
Mining
Ground water
“Deep
exploration” /
modeling
Modeling
ore zones
Sediments &
aggregates
MINERAL
RESOURCES
Global change
Geo-energy
ENERGY &
ENVIRONMENT
Mineral
potential
mapping
* Based on 2013 data/interviews
Highlights of geophysics in GTK
1. Geophysical mapping programs, databases & research
• Airborne geophysical mapping 1950’s – 2007
• Regional gravity 1972 – 2009 (cont)
• Petro physical program 1950’s –1990 (cont)
• Marine mapping program (cont)
• Deep seismic projects (FIRE, HIRE)
2. Geophysical field measurements
- 5-10 field groups
- all base methods (EM, IP, magnetic, gravity)
- ”special” methods (especially for deep EM), bore-hole, etc
EM Survey
Deep seismic survey (HIRE)
Highlights of geophysics in GTK
3. Engineering & environmental applications
Increased use of geophysics for engineering,
environmental and groundwater studies
since 1990’s
4. Export projects
- Geophysical (airborne) mapping project
in Africa and Europe in 1990’s and 2000’s
- Afghanistan geophysics (2013-2017)
5. R&D and instrumentation
• Airborne systems, especially the electromagnetics, also
software for map production & interpretation
• petrophysical laboratory, other EM instruments
Airborne mapping program (1950’s 2007)
Started in 1951
 1951 Magnetic
 1954 EM
 1956 Gamma radiation
 Since 1956 Magn + EM +
radition
Airborne data cover whole country
Magnetic
tot
gamma radiation
K, Th, U, tot
Electrical conductivity
Re, Im, ρa (1, 2 or 4 freq)
I National survey project (highaltitude survey)
• 400 m line spacing, 150 m
flight altitude
• Magnetic, EM, radiometric
• Competed 1972
II National survey project
(low altitude, high resolution)
• Started in 1972
• Completed in 2008
• 200 m line spacing, 30 m
flight altitude
• EM, magnetic, radiometric
• 1, 2 or 4 frequencies
Regional gravity mapping program 1972-2010
Regional gravity database
1-8 points/km2
• GTK and FGI data, 86 600 km2
• Airborne gravity, 17 100 km2
The program has ended, but
measurements continue
–
2-3 teams in operation whole
year (groundwater & minerals)
Petrophysical mapping program 1950’s – 1990 (cont.)
Petrophysical database
> 130 000 samples
- magnetic, density
- (radiation, conductivity, IP, seismic)
Program ended, but 3 laboratories
measures
-magnetic (susc, reman, ams)
- res/IP, conductivity, seismic vp,
- porosity, density, thermal properties
- gamma radiatiation, magn. mineral.
Ground geophysics “program”
Ground geophysics database
all old data of EM (Slingram), Magn, Grav,
IP and VLF (and some others)
5 field teams measure (systematic)
• Gravity
• Magnetic
• Electromagnetic
• IP/RES
……….
Other field measurements
- TEM (30-300m)
- FEM/Sampo (100-1000m)
- FEM/AMT (>1000m))
• Seismic, ERT
• Bore-hole techniques
Examples of recent geophysical activities
Mineral Resources:
• Airborne TEM mapping of Vihanti and Keitele (2008) – data integration
• Airborne TEM mapping of Enontekiö (2012)
• Airborne gravity of Salla and Savukoski (2011)
• Airborne EM of Outokumpu (2013)
• 3D modeling of ore potential zones (starting) – Reflection seismic & integration
• Research of petrophysics for exploration
Energy and Environment:
• Permafrost characterization in Canada,
Russia and Greenland
• Modeling low–temperature geothermal
systems
Groundwater :
• 3D modeling of groundwater areas
Integration of seismic, electrical conductivity and
drilling data (Vihanti are 2008)
Research by GTK geophysicists

Petrophysics,
Emplacement and magnetic fabric of rapakivi granite intrusions within Wiborg and Åland rapakivi granite batholiths in Finland, 2014 (Karell, F.,
Ehlers, C. & Airo, M-L, Tectonophysics)
Precambrian Supercontinents, 2014 (Pesonen, L, Halls & Mertanen S, editors, Precambrian Research)
Paleomagnetic and geochemical studies of the Mesoproterozoic Satakunta dyke swarms, Finland, with implications for a Northern Europe – North
America (NENA) connection within Nuna supercontinent, 2014 (Salminen J, Mertanen S, Evans D.A.D., Wang Z., Precambrian Research)
Paleomagnetism of Mesoproterozoic Satakunta sandstone, Western Finland, 2014 (Klein, R., Pesonen, L.J., Salminen, J., Mertanen, S.,
Precambrian Research)
Geophysical characteristics of Aswa shear, Nagasongola discontinuity and ring dyke complex in Uganda, 2014 (Ruotoistenmäki, Journal of
African Earth Sciences)

3D modelling of ore zones
2D reflection seismic investigations at the Kevitsa Ni-Cu-PGE deposit, northern Finlands, 2012 (Koivisto, E, Alireza, M., Heikkinen, P, Heinonen, S
and Kukkonen I., Geophysics)
Delineating ophiolite-derived host rocks of massive sulfide Cu-Co-Zn deposits with 2D high-resolution seismic reflection data in Outokumpu,
Finland, 2012 (Kukkonen, I, Heinonen, S., Heikkinen P., Sorjonen-Ward. P, Geophysics)

EM and bore-hole applications
High-resolution Magnetotelluric studies of the Archean-Proterozoic Border zone in the Fennoscandian Shield, Finland. 2012 (Vaittinen, T., Korja,
T., lahti, I., Geophysical Journal International)
Geotomographic studies for ore explorations with the EMRE system, 2014. (Korpisalo, Arto, Measurement)
Borehole Antenna Considerations in the EMRE System: Frequency Band 312.5-2500 kHz, 2013. (Korpisalo, A., The Open Geology Journal).
Radiowave imaging (RIM) for determining the electrical conductivity of the rock in borehole section OL-KR4-OL-KR10 at Olkiluoto, 2005, 2014
(Korpisalo, A. & Heikkinen, Exploration Geophysics)
Example of R&D
RIM – conductivity mapping space between bore-holes
International Journal of Geophysics, Volume 2014. http://dx.doi.org/10.1155/2014/401654. Characterization of
Geotomographic Studies with the EMRE System. Arto Korpisalo