?url_ver=Z39.88-2004&rft_id=Q+23%2F2009%2F43&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=https%3A%2F%2Fepisodesplatform.eu%2Feprints%2F2108%2F&rft.title=HIRE+Seismic+Reflection+Survey+in+the+Pyh%C3%A4salmi+Zn-Cu+mining+area%2C+central+Finland&rft.creator=Kukkonen%2C+Ilmo&rft.creator=Heikkinen%2C+Pekka&rft.creator=Heinonen%2C+Suvi&rft.creator=Laitinen%2C+Jukka&rft.subject=Other-additional+study&rft.subject=Pyh%C3%A4j%C3%A4rvi&rft.subject=Underground+mining&rft.description=A+seismic+reflection+survey+comprising+four+vibroseis+lines+(total+length+of+25.1+km)+and+two+explosion+seismic+lines+(total%0D%0Alength+12.5+km)+was+carried+out+in+the+Pyh%C3%A4salmi+Zn-Cu+mining+area%2C+in+central+Finland%2C+in+November%2C+2007.+The+survey+is+a%0D%0Apart+of+the+project+HIRE+(High+Resolution+Reflection+Seismics+for+Ore+Exploration+2007-2010)+of+the+Geological+Survey+of%0D%0AFinland+(GTK).+The+Pyh%C3%A4salmi+survey+was+done+in+co-operation+with+the+Pyh%C3%A4sami+Mine+Oy.%0D%0A+The+Pyh%C3%A4salmi+area+is+well+known+for+its+massive+Zn-Cu+sulphide+deposits+in+altered+metavolcanic+rocks+in+the+thoroughly%0D%0Adeformed+and+folded+host+rocks+of+the+1.88-1.93+Ga+Savo+Belt.+The+HIRE+results+show+a+detailed+structure+of+the+uppermost%0D%0A5+km+of+crust.+The+most+prominent+feature+is+the+bimodal+general+characteristics+of+the+reflectivity.+An+E-NE+dipping+strongly%0D%0Areflective+layer+was+detected+at+depths+exceeding+1-2.5+km.+Above+this+layer+the+reflectivity+is+very+weak+and+not+simple+to%0D%0Acorrelate+with+surface+geology.+Drill+hole+data+from+the+mine+suggest+that+the+strong+reflectivity+could+be+attributed+to+mafic%0D%0Avolcanic+rocks+with+interlayers+of+felsic+volcanics+and+pegmatite+dykes+at+least+in+the+uppermost+part+of+the+reflector.%0D%0A+Using+large-scale+reflection+seismic+data+of+the+FIRE-1+transect+the+strongly+reflective+system+can+be+correlated+to+a+50+km%0D%0Awide+and+10+km+deep+synform+structure+of+the+Savo+Belt.+Surface+geology+suggests+that+the+synform+and+the+strongly%0D%0Areflective+layer+represent+mainly+mafic+volcanic+rocks+with+felsic+interlayers+as+well+as+metasediments.+Considerable%0D%0Ashortening+has+taken+place+in+E-W+direction%2C+and+several+deep%2C+mostly+east-dipping+(thrust)+faults+can+be+identified+between%0D%0APyh%C3%A4salmi+and+the+Archaean-Proterozoic+boundary.+The+Ruotanen+and+the+Mullikkor%C3%A4me+Schist+Belts+are+both+located+in+the%0D%0Aimmediate+vicinity+of+interpreted+deep+faults+and+boundaries+of+up-thrown+blocks.%0D%0A+The+Pyh%C3%A4salmi+deep+ore+deposit+is+located+at+the+upper+boundary+of+the+strongly+reflective+layer+where+the+reflectors%0D%0Abeneath+the+deposit+seem+to+form+an+antiform-like+structure.+The+reflection+image+of+the+pear-shaped+deep+ore+body+at+the%0D%0Adepth+of+1.1+-+1.5+km+is+characterized+by+strong+reflectors+beneath+and+on+the+eastern+side+of+the+massive+ore.+The+observed%0D%0Areflectivity+is+due+to+impedance+contrast+between%2C+on+one+hand%2C+the+massive+ore+and+its+host+rocks+(mafic+volcanic+rocks+and%0D%0Ainterlayers+of+felsic+rocks)%2C+and+on+the+other+hand%2C+to+internal+reflection+contrasts+within+the+host+rocks.%0D%0A+The+data+is+applied+for+indicating+potential+targets+for+further+exploration+and+possible+analogues+of+the+Pyh%C3%A4salmi%0D%0Adeposits.&rft.publisher=GEOLOGICAL+SURVEY+OF+FINLAND&rft.date=2010-02-25&rft.type=Reports&rft.type=NonPeerReviewed&rft.identifier=++Kukkonen%2C+Ilmo+and+Heikkinen%2C+Pekka+and+Heinonen%2C+Suvi+and+Laitinen%2C+Jukka++(2010)+HIRE+Seismic+Reflection+Survey+in+the+Pyh%C3%A4salmi+Zn-Cu+mining+area%2C+central+Finland.++Technical+Report.+GEOLOGICAL+SURVEY+OF+FINLAND.+++++&rft.relation=http%3A%2F%2Ftupa.gtk.fi%2Fraportti%2Farkisto%2Fq23_2009_43.pdf&rft.relation=Q+23%2F2009%2F43