Cost-Effective Seismic Exploration: 2D Reflection Imaging at the Kylylahti Massive Sulfide Deposit, Finland

Minerals

Emilia Koivisto¹  Gardar Gislason²  Suvi Heinonen²  Marek Wojdyla³  Stefan Buske⁴  Felix Hloušek⁴  Michal Malinowski⁵ 

[1] Department of Geosciences and Geography, University of Helsinki, PL 68, 00014 Helsinki, Finland;Geological Survey of Finland, Vuorimiehentie 5, 02151 Espoo, Finland;Geopartner Ltd., ul. Skośna 39B, 30-383 Kraków, Poland;Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg, Gustav-Zeuner-Str. 12, D-09599 Freiberg, Germany;Institute of Geophysics, Polish Academy of Sciences, Ks. Janusza 64, 01-452 Warsaw, Poland;

关键词: seismic reflection;    massive sulfide;    seismic imaging;    mineral exploration;    cost-effective seismics;    pre-stack depth migration;    Finland;    Outokumpu;   

DOI  :  10.3390/min9050263

来源: DOAJ

【 摘 要 】

We show that by using an advanced pre-stack depth imaging algorithm it is possible to retrieve meaningful and robust seismic images with sparse shot points, using only 3−4 source points per kilometer along a seismic profile. Our results encourage the use of 2D seismic reflection profiling as a reconnaissance tool for mineral exploration in areas with limited access for active seismic surveys. We used the seismic data acquired within the COGITO-MIN project comprising two approximately 6 km long seismic reflection profiles at the polymetallic Kylylahti massive sulfide mine site in eastern Finland. The 2D seismic data acquisition utilized both Vibroseis and dynamite sources with 20 m spacing and wireless receivers spaced every 10 m. For both source types, the recorded data show clear first breaks over all offsets and reflectors in the raw shot gathers. The Kylylahti area is characterized by folded and faulted, steeply dipping geological contacts and structures. We discuss post-stack and pre-stack data processing and compare time and depth imaging techniques in this geologically complex Precambrian hardrock area. The seismic reflection profiles show prominent reflectors at 4.5−8 km depth utilizing different migration routines. In the shallow subsurface, steep reflectors are imaged, and within and underneath the known Kylylahti ultramafic body reflectivity is prominent but discontinuous.

【 授权许可】

Unknown