Seismic imaging of the crustal structure in the Sodankylä region (Finland): unveiling the Central Lapland Greenstone Belt’s mineral potential

SUMMARY The XSoDEx (eXperiment of Sodankylä Deep Exploration) project acquired in total 82 km of seismic reflection and refraction data to improve the understanding of the crustal composition and, consequently, the mineral systems of the Sodankylä region in Northern Finland. The Sodankylä region is part of the Central Lapland Greenstone Belt, which is famous for its mineral resources. Here, we present the first subsurface images resulting from the seismic reflection and refraction data processing, and provide the first geological interpretation of the data. Our workflow comprised time domain signal processing, migration velocity model building and finally, focusing pre-stack depth migration. The results along the acquired seismic profile lines show a rich inventory of imaged reflectors throughout the upper crust, which in some parts can be correlated clearly with geological features at the surface and also show the complex structure of the lithological units of the Central Lapland Greenstone Belt in the investigation area. Moreover, the presumable top of the Archaean basement can be traced through all lines. The basement is partly bent up to the shallow subsurface. In places, the basement forms a dome-like outcrop. The derived results of the seismic data are in good accordance with earlier interpretations of adjacent seismic investigations. The XSoDEx seismic profiles connect the imaged reflective structures to these surveys, which were acquired over known mineral deposits.