New zircon data supporting models of short-lived igneous activity at 1.89 Ga in the western Skellefte District, central Fennoscandian Shield

Abstract

Abstract. New U-Th-Pb zircon data (SIMS)

3D constraints and finite-difference modeling of massive sulfide deposits: The Kristineberg seismic lines revisited, northern Sweden

“…Due to its economic significance and the geometrically challenging structural framework of the Kristineberg deposit, four reflection seismic profiles (Figures 1 and 2) with various resolution and research objectives, totaling a length of about 70 km, have been acquired Dehghannejad et al, 2010). The seismic data in conjunction with available geologic Skyttä et al, 2010Skyttä et al, , 2011 and geophysical data, such as gravity and magnetic data (Malehmir et al, , 2009a(Malehmir et al, , 2009b and magnetotelluric data (Hübert et al, 2009;Garcia et al, 2012), have allowed the construction of a 3D geologic Manuscript received by the Editor 24 November 2011; revised manuscript received 23 March 2012; published online 6 September 2012. model of the study area. However, several questions still remain to be answered.…”

Re-processing and interpretation of 2D seismic data from the Kristineberg mining area, northern Sweden

“…9). It is interpreted to be a structural basement to the Skellefte metavolcanic and metasedimentary rocks in Skyttä et al, 2011), showing (a) syn-extensional volcanism (e.g., Skellefte volcanic rocks), mineralization, sedimentation and intrusive activity (e.g., Viterliden intrusion). (b) Subsequent crustal shortening leading to basin inversion (Bauer et al, 2011) and related transposition of the mineralized horizons.…”

“…Despite these geological complexities and challenges, the Kristineberg area has been extensively studied to develop contact relationships between the ore bearing rocks of the Skellefte metavolcanic and metasedimentary group and its surrounding intrusive rocks (Allen et al, 1996;Billström and Weihed, 1996;Dehghannejad et al, 2010Dehghannejad et al, , 2012Kautsky, 1957;Malehmir et al, 2006;Skyttä et al, 2010Skyttä et al, , 2011Weihed et al, 1992). Two large-scale semi-parallel seismic profiles (Profiles 1 and 5) approximately 25 km long each were acquired in the Kristineberg area in late August and early September 2003 (Fig.…”

Palaeoproterozoic porphyry Cu–Au, intrusion-hosted Au and ultramafic Cu–Ni deposits in the Fennoscandian Shield: Temporal constraints using U–Pb geochronology

“…The VMS deposits in the Skellefte district formed during extension at 1.89 Ga Skyttä et al, 2011;Skyttä et al, 2012) and are coeval with granitoid to mafic (GI) magmatism in the JIC. Progressive subduction led to dehydrating reactions in the subducting slab and hydrous partial melting at the base of the crust or metasomatised mantle wedge.…”

“…Volcanic units hosting the VMS deposits have been dated using the U-Pb zircon method, yielding ages of 1.90-1.88 Ga, see Table 1 Montelius, 2005;Skyttä et al, 2011;Welin, 1987). The overlying Vargfors Group is dominated by shallow marine, coarse epiclastic rocks and intercalated dominantly mafic volcanic rocks dated at 1875± 4 Ma .…”