2. 45 Ga break-up of the Archaean continent in Northern Fennoscandia: Rifting dynamics and the role of inherited structures within the Archaean basement

Skyttä, Pietari; Piippo, Simo; Kloppenburg, A.; Corti, Giacomo

doi:10.1016/j.precamres.2019.02.004

Cited by 21 publications

(3 citation statements)

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“…Preexisting structures, along with early phases of rifting, can exert a considerable influence over the distribution of fault activity and the geometry and evolution of syn‐rift depocenters during rifting. Pervasive basement fabrics can directly control the geometry of faults and the (rift) basins they bound (e.g., Daly et al, ; Fazlikhani et al, ; Gontijo‐Pascutti et al, ; Morley et al, ; Paton & Underhill, ; Phillips et al, ; Phillips et al, ; Salomon et al, ; Skyttä et al, ; Vasconcelos et al, ). Discrete structures may also locally perturb the regional stress field, causing faults to strike oblique to the regional extension direction (Corti, ; Corti et al, ; Morley, , ; Philippon et al, ; Rotevatn et al, ; Samsu et al, ).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

et al. 2019

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The northern North Sea rift evolved through multiple rift phases within a highly heterogeneous crystalline basement. The geometry and evolution of syn-rift depocenters during this multiphase evolution and the mechanisms and extent to which they were influenced by preexisting structural heterogeneities remain elusive, particularly at the regional scale. Using an extensive database of borehole-constrained 2D seismic reflection data, we examine how the physiography of the northern North Sea rift evolved throughout late Permian-Early Triassic (RP1) and Late Jurassic-Early Cretaceous (RP2) rift phases, and assess the influence of basement structures related to the Caledonian orogeny and subsequent Devonian extension. During RP1, the location of major depocenters, the Stord and East Shetland basins, was controlled by favorably oriented Devonian shear zones. RP2 shows a diminished influence from structural heterogeneities, activity localizes along the Viking-Sogn graben system and the East Shetland Basin, with negligible activity in the Stord Basin and Horda Platform. The Utsira High and the Devonian Lomre Shear Zone form the eastern barrier to rift activity during RP2. Toward the end of RP2, rift activity migrated northward as extension related to opening of the proto-North Atlantic becomes the dominant regional stress as rift activity in the northern North Sea decreases. Through documenting the evolving syn-rift depocenters of the northern North Sea rift, we show how structural heterogeneities and prior rift phases influence regional rift physiography and kinematics, controlling the segmentation of depocenters, as well as the locations, styles, and magnitude of fault activity and reactivation during subsequent events.

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Section: Introductionmentioning

confidence: 99%

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

et al. 2019

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“…The regional trend of the ca. 2450 Ga Pääjärvi dykes is therefore interpreted to be represented by the NNW-trending dykes and these are related to regionally extensive parallel structures associated with northeast-southwest extension (Skyttä et al, 2019). The structural restoration also roughly aligns dykes with ca.…”

Section: Rotation Of the Pudasjärvi Blockmentioning

confidence: 91%

“…In order for both the Pääjärvi and Tohmajärvi swarms to fit approximately within the context of their counterparts in the Superior craton (Matachewan and Marathon swarms, respectively), Karelia-Kola is positioned such that is south of the East half of the Superior craton and southeast of the Wyoming craton(Figure 2-17). The Pääjärvi dykes have two dominant trends including a local subset with a NE trend (Lashkujärvi) and a more regional subset with a NW trend, which are also tied to regional structures related to northeast extension(Skyttä et al, 2019). This ca.…”

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confidence: 98%

Testing the Paleogeography of Late Archean Supercraton Superia using Pre-Breakup 2.51-1.98 Ga dyke and Sill Provinces – with a Focus on the Relationship Between the Karelia-Kola and Superior Cratonic Fragments

Davey¹

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Archean cratons are dispersed crustal fragments derived from larger ancestral landmasses. Their individual and combined study in paleogeographic reconstructions reveal details relevant to understanding larger Archean tectonic systems. Canada's Superior craton is considered the central piece of the late Archean Superia supercraton paleogeographic reconstruction that also includes the Karelia-Kola (Finland/Russia), Wyoming (USA), and Hearne (Canada) cratons. The relationship between Superior and Karelia-Kola is of interest because the position of the Karelia-Kola craton within the context of the Superia reconstruction is not fully resolved. Dyke swarm correlations based on age and geometry indicate that Karelia-Kola and Superior were 'nearest-neighbours', yet paleomagnetic studies disagree. However, these data are complicated due to multiple metamorphic overprints, and are limited by a lack of high-precision U-Pb ages. The focus of this study is to test the correlation between the Karelia-Kola and Superior cratons by integrating U-Pb geochronology, whole-rock major, trace element and Sm-Nd isotope geochemistry, and dyke swarm geometry. These methods confirm the occurrence of sharply timed large igneous provinces (LIP) in Karelia-Kola correlated to Superior using geochronology, test whether the magmas were from a common source, and refine the paleogeographic Superia reconstruction by incorporating regional dyke trends. This study presents nine ages from dykes and sills that confirm LIP correlations between the Karelia-Kola and Superior cratons at ca. 2.40 Ga, 2.22 Ga, 2.11 Ga and 1.98 Ga, and three ages at ca. 2.32 Ga confined to Karelia-Kola. Geochemical studies were completed on mafic magmatic events at ca. 2.22 Ga and 2.11 Ga. The evaluation of 2.22 I have been fortunate to work under the guidance of three passionate supervisors. Dr. Wouter Bleeker's role has been fundamental to my development as a scientist, and the progression of this thesis as a whole. I would like to thank Dr. Richard E. Ernst for his encouragement to pursue graduate school in 2010 and again in 2014, and for his belief in me over the years. I am appreciative to have had Dr. Brian Cousens across the hall, whose open-door was a necessity for understanding and interpreting geochemistry. I would also like to acknowledge the unofficial supervision I received from Dr. Sandra L. Kamo at the University of Toronto. She is a skilled scientist and a natural teacher who has made a substantial contribution to this thesis. Sandra let me learn geochronology at my own pace, even when that meant I might not do something perfectly the first time. When I did make a mistake, we discussed it not as a failure, but as a learning experience. In doing so, she gave me the confidence to try more lab work, then helped me realize that it is something that I can do, and more importantly, something that I really enjoy.

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Joint Interpretation of Magnetotelluric and Potential Field Data From North-Eastern Norrbotten, Sweden

Vadoodi

Rasmussen

2022

Pure Appl. Geophys.

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Potential field data in databases of the Geological Survey of Sweden (SGU) combined with newly acquired broadband magnetotelluric data are used to map and interpret geological units and structures of a 200 km by 250 km area in the Paleoproterozoic Norrbotten ore province (northern Sweden, latitudes 66°–68.5° and longitudes 19°–24°). In order to achieve this, a new approach is proposed with respect to extracting and analysing the possible correlation between modelled physical properties as well as their patterns with respect to depth variation within the crust. In this study, we propose the use of a neural net self-organising map procedure (SOM) for simplification, data reduction, and domain classification of the models derived from independent 3-D geophysical inversion of magnetotelluric, gravity, and magnetic data. The crustal model of the electrical conductivity structure was obtained from previous 3-D inversion of the magnetotelluric data. Processing and 3-D inversion of the regional magnetic and gravity field data were performed using an open-source object-oriented code called SimPEG. The input data to the SOM analysis contain resistivity, magnetic susceptibility, and density model values within the Norrbotten area for some selected depth levels of the entire crust. The domain classification is discussed with respect to the geological boundaries and composition of the crust. Consistency between model domain classification and geological boundaries is observed in general but an apparent discrepancy is noted for some areas. The reason for the apparent discrepancy is likely related to that most geological boundaries represent surface features whereas the geophysical data includes information at depth.

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2. 45 Ga break-up of the Archaean continent in Northern Fennoscandia: Rifting dynamics and the role of inherited structures within the Archaean basement

Cited by 21 publications

References 66 publications

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

Testing the Paleogeography of Late Archean Supercraton Superia using Pre-Breakup 2.51-1.98 Ga dyke and Sill Provinces – with a Focus on the Relationship Between the Karelia-Kola and Superior Cratonic Fragments

Joint Interpretation of Magnetotelluric and Potential Field Data From North-Eastern Norrbotten, Sweden

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2. 45 Ga break-up of the Archaean continent in Northern Fennoscandia: Rifting dynamics and the role of inherited structures within the Archaean basement

Cited by 21 publications

References 66 publications

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

Testing the Paleogeography of Late Archean Supercraton Superia using Pre-Breakup 2.51-1.98 Ga dyke and Sill Provinces – with a Focus on the Relationship Between the Karelia-Kola and Superior Cratonic Fragments

Joint Interpretation of Magnetotelluric and Potential Field Data From North-Eastern Norrbotten, Sweden

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2. 45 Ga break-up of the Archaean continent in Northern Fennoscandia: Rifting dynamics and the role of inherited structures within the Archaean basement