Affiliation:
1. Division of Geosciences and Environmental Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden
Abstract
AbstractFelsic volcanic rocks (c. 1.91–1.89 Ga) and interlayered limestone, hosting Zn–Pb–Ag ± Cu ± Au ± Fe sulphide and Fe oxide deposits, characterize the Bergslagen lithotectonic unit, Svecokarelian orogen, south-central Sweden. Three sulphide mines are currently in operation. Siliciclastic sedimentary rocks stratigraphically envelop this volcanic succession and all the rocks are intruded by a dominant calc-alkaline, c. 1.91–1.87 Ga plutonic suite. Fabric development associated with folding and localized shear deformation followed at c. 1.87–1.86 Ga (D1) and was succeeded by strongly partitioned strain (D2). Dextral transpression along steeply dipping, WNW–ESE or NW–SE shear zones prevailed in the northern and southern domains, whereas major folding with east to northeasterly axial surface traces and shearing along limbs occurred in the central domain. Open folding (D3) subsequently affected the western areas. Polyphase metamorphism under low-pressure and variable temperature conditions included anatexis at c. 1.86 Ga (M1) and 1.84–1.80 Ga (M2). More alkali–calcic magmatic activity, combined with the emplacement of anatectic granite and pegmatite, overlapped and succeeded the M1 and M2 migmatization events at c. 1.87–1.83 Ga and c. 1.82–1.75 Ga, respectively. The younger granites are genetically linked in part to W skarn deposits and host Mo sulphide mineralization. Switching between retreating and advancing subduction systems during three separate tectonic cycles along a convergent, active continental plate margin is inferred.
Publisher
Geological Society of London
Reference193 articles.
1. Radiometric dating of Svecokarelian metarhyolites and prekinematic granitoids from Bergslagen, south central Sweden;Geologiska Föreningens i Stockholm Förhandlingar,1984
2. Zircon ages of metavolcanic and synorogenic granitic rocks from the Svärdsjö and Yxsjöberg areas, south central Sweden;Geologiska Föreningens i Stockholm Förhandlingar,1983
3. Proterozoic sutures and terranes in the southeastern Baltic Shield interpreted from BABEL deep seismic data
4. Ahl M. , Bergman S. , Bergström U. , Eliasson T. , Ripa M. & Weihed P. 2001. Geochemical Classification of the Plutonic Rocks in Central and Northern Sweden. Sveriges geologiska undersökning Rapporter och meddelanden, 106.
5. Ahlberg P. 1986. Den svenska kontinentalsockelns berggrund. Sveriges geologiska undersökning Rapporter och meddelanden, 47.
Cited by
33 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献