Located at an important intersect between orogenic Au deposits in Sweden’s Gold Line and volcanicmassive sulphide (VMS) deposits in the Skellefte Mining District, the Barsele area is of high interest.Currently, the Barsele deposit consists of the Norra VMS deposit and 3 intrusive-hosted orogenic Audeposits: Avan, Central, and Skiråsen which are hosted in a 1876 ± 10 Ma early orogenic granodiorite(Thomas, et al., 2019). The aim of this thesis is to create a structural and geological model of the Barsele area whilst improvingthe understanding of the structural controls on VMS and intrusive-hosted Au mineralisation in thearea. Furthermore, this thesis aims to highlight prospective areas for future study and targeting inhopes to aid mineral exploration in the region. Geological mapping has been carried out in an area ofaround 440km2, with emphasis on structural measurements. 381 outcrop observations and more than4200 structural features were recorded using a combination of traditional and digital mappingmethods, including the use of Field Move by Petroleum Experts. The area was chosen as part of AgnicoEagle, Sweden’s mineral exploration project. The region has been affected by two dominant, syn-metamorphic cleavage forming events. The eventsdefine the main phase of the Svecofennian Orogeny which has produced ubiquitous slaty cleavage, Ndirected thrusts, and steeply inclined axial surfaces throughout the region. The region is characterisedby important N-S displacements with sinistral movement along major N-S trending transfer faults. Theabsence of strike-slip shearing in D1 structures indicates that D1 deformation was dominantly coaxialin nature and developed due to SW-NE crustal shortening. Along with this, a major ESE-WNW-strikingshear zone is identified with an inferred syn-extensional (D1) origin. D2 involved fault inversion and reactivation of syn-extensional faults as reverse shear zones. E-Wtrending lineations along more brittle SSW-NNE striking shear zones inferred to indicate an E-Worientation for crustal shortening during D2. D3 caused reactivation of the N-S-striking high-strain zones with reverse kinematics. This reactivationof trending shear zones resulted in strain partitioning into N-S zones. D3 is manifested by broad, open,N-NE trending upright folds of bedding and S2 foliation. 1st, 2nd, and 3rd order D3 structures have beencharacterised and illustrated by combining a range of data including outcrop observations, regionalStereonets, magnetic anomaly maps, and other geophysical maps.

The Barsele area is located in the "Gold Line", southwest of the volcanogenic massive sulphide (VMS) Skellefte district which hosts more than 85 known VMS-deposits where some are gold-bearing. The Barsele area consists of the Central, Avan and Skiråsen intrusion hosted gold deposits, the Norra gold-bearing VMS-deposit and the Risberget zone. This study includes a geochronological study of two coherent volcanic rocks from the Norra zone using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry and Scanning Electron Microscope images of zircons and also includes petrographic microscopy of thin sections and lithogeochemical data used in classification diagrams.  This study presents two new LA-ICP-MS zircon U-Pb ages for VMS-hosting volcanic rocks from the Barsele area: o   1956.8 ± 6.47 Ma (n: 17, MSWD: 0.99), sample A from a hydrothermally altered volcanic rock  o   1952.2 ± 14.5 Ma (n: 6, MSWD: 1.1), sample B from a rhyolite-dacite  The new U-Pb age constraints presented in this study indicate that the volcanic rocks of the Norra zone are older than the volcanic rocks in the Skellefte Group. The results presented in this report together with the earlier dated c. 1.96 Ga metadacite suggests that the volcanic rocks of the Barsele area are located at a lower chronostratigraphic level than the Skellefte Group, i.e., at the chronostratigraphically lower Bothnian Supergroup. Additionally, the results presented here conclude that two VMS-events can be delineated by geochronological data which further opens up for the question if the Barsele area belong to an older arc system (e.g., the Knaften arc) or were part of an arc system evolving continuously between 1.95-1.88 Ga (e.g., the Knaften-Skellefte arc). / Barsele, Västerbottens län, norra Sverige, ligger i ett område som kallas för Guld linjen och är beläget sydväst om Skelleftefältet där mer än 85 kända förekomster av massiva sulfidmalmer (VMS), vissa guldförande, förekommer. Barseleområdet är uppdelat i Central, Avan och Skiråsen zonen, Norra zonen och Risberget zonen där Norra zonen är en guldförande VMS-fyndighet. Denna studie inkluderar en geokronologisk studie av zirkoner från två vulkaniter från Norra zonen som har analyserats med Laser Ablation Inductively Coupled Plasma Mass Spectrometry och avbildats med svepelektronmikroskop samt petrografisk studie av två tunnslip och klassificeringsdiagram baserade på litogeokemisk data. Denna studie presenterar två nya LA-ICP-MS zirkon U-Pb åldrar för VMS-förande vulkaniter i  Barseleområdet:  o   1956.8 ± 6.47 Ma (n: 17, MSWD: 0.99), prov A från en hydrotermalt omvandlad vulkanisk bergart o   1952.2 ± 14.5 Ma (n: 6, MSWD: 1.1), prov B från en ryolit-dacit De två nya  U-Pb zirkon åldersbestämningarna som presenteras i denna studie indikerar att de vulkaniska bergarterna i Norra zonen är äldre än de vulkaniska bergarterna som tillhör Skelleftegruppen. Vidare antyder de presenterade åldrarna i denna studie tillsammans med den tidigare genomförda dateringen av en metadacit (cirka 1.96 Ga) på att de vulkaniska bergarterna i Barseleområdet kan tillhöra suprakrustala bergarter tillhörande Bottniska bassängen. Barseleområdet föreslås därför förekomma vid en lägre kronostratigrafisk nivå jämfört med Skelleftegruppen, det vill säga vid samma kronostratigrafisk nivå som Bottniska Supergruppen. Utifrån de resultat som presenteras här kan slutsatsen att två VMS-områden kan avgränsas av geokronologiska data som ytterligare öppnar för frågan om Barsele-området tillhör ett äldre bågsystem (t.ex. Knaften-bågen) eller var en del av ett bågsystem som utvecklades mellan 1.95-1.88 Ga (t.ex. Knaften-Skelleftebågen).