Brittle tectonothermal evolution in the Forsmark area, central Fennoscandian Shield, recorded by paragenesis, orientation and 40Ar/39Ar geochronology of fracture minerals

Sandström, B; Tullborg, Eva‐Lena; Larson, Sven Åke; Page, Laurence

doi:10.1016/j.tecto.2009.08.006

Cited by 38 publications

(52 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15, Table 2) suggests multiphase reactivation of the brittle deformation zones in different mineral stability fields and this is supported by the analysis of the fault-slip data (Saintot et al, 2011). Epidote formed when the rocks behaved in a ductile-brittle manner around 1.8 Ga and probably later in the brittle regime, but prior to the initiation of the 1.1-0.9 Ga tectonic development in Scandinavia (Sveconorwegian orogeny; Sandström et al, 2009). By contrast, hematite-stained adularia and laumontite formed in connection with (Sandström et al, 2009) and possibly also prior to the Sveconorwegian event.…”

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 64%

“…Inspection of the total magnetic field anomaly map (Fig. 6) suggests that at least the bulk strike-slip (Sandström et al, 2008b(Sandström et al, , 2009, inside an inferred brittle deformation zones inside the Forsmark tectonic lens (Carlsten et al, 2006;Stephens et al, 2007), modelled as a steeply dipping zone with ENE-WSW strike (ZFMENE0060C, see also Fig. 8A).…”

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 99%

“…The fractures along a deformation zone are coated or filled by minerals belonging to different mineral groups, which formed at different times during the tectonic evolution (Sandström et al, 2008b(Sandström et al, , 2009). Examples include epidote, laumontite, pyrite and clay minerals, in order from older to younger.…”

Section: Identification and Characterisation Of Brittle Deformation Zmentioning

confidence: 99%

“…Epidote formed when the rocks behaved in a ductile-brittle manner around 1.8 Ga and probably later in the brittle regime, but prior to the initiation of the 1.1-0.9 Ga tectonic development in Scandinavia (Sveconorwegian orogeny; Sandström et al, 2009). By contrast, hematite-stained adularia and laumontite formed in connection with (Sandström et al, 2009) and possibly also prior to the Sveconorwegian event. Other minerals, including sulphides, quartz, adularia and clay minerals, formed later during the Phanerozoic (Sandström et al, 2009).…”

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 99%

“…Previously published work has addressed some aspects in the current paper and is also made use of here. These aspects include reflection seismic data (Bergman et al, 2006;Brojerdi et al, 2013;Juhlin and Stephens, 2006), geochronological data bearing on the geological evolution (Hermansson et al, 2007(Hermansson et al, , 2008aSandström et al, 2009;Söderlund et al, 2009), hydrothermal alteration (Petersson et al, 2012;Sandström et al, 2008a) and the reconstruction of paleostress fields throughout geological time (Saintot et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Review of the deterministic modelling of deformation zones and fracture domains at the site proposed for a spent nuclear fuel repository, Sweden, and consequences of structural anisotropy

Stephens

Follin²,

Petersson³

et al. 2015

Tectonophysics

View full text Add to dashboard Cite

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 64%

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 99%

Section: Identification and Characterisation Of Brittle Deformation Zmentioning

confidence: 99%

Section: Spatial Distribution and Geological Properties Of Modelled Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Review of the deterministic modelling of deformation zones and fracture domains at the site proposed for a spent nuclear fuel repository, Sweden, and consequences of structural anisotropy

Stephens

Follin²,

Petersson³

et al. 2015

Tectonophysics

View full text Add to dashboard Cite

Polyphase vein mineralization in the Fennoscandian Shield at Åkerlandet, Järvsand, and Laisvall along the erosional front of the Caledonian orogen, Sweden

et al. 2016

View full text Add to dashboard Cite

The Åkerlandet, Järvsand, and Laisvall deposits in Sweden are calcite-fluorite-sulfide vein deposits and occurrences located close to the current erosional front of the Caledonian orogen and hosted by crystalline basement rocks in the Fennoscandian Shield. At Laisvall, basement-hosted veinlets occur beneath Ediacaran to Cambrian sandstones that host a strata-bound Pb-Zn deposit. The mineralized fractures at Åkerlandet and Järvsand occur along fault systems oriented N–S to NNW–SSE. Veins or veinlets strike NNW–SSE and NW–SE at Åkerlandet, NNE–SSW at Järvsand, and NNW–SSE and NNE–SSW to NE–SW at Laisvall. At Åkerlandet and Järvsand, fractures acted as conduits for hydrothermal fluids of variable composition and formed during separate tectonic events. At Åkerlandet, the fault zone with NNW–SSE strike shows kinematic indicators consistent with ~NE–SW bulk horizontal extension. At Järvsand, the calcite-fluorite-galena veins formed along R-Riedel shears related to the host N–S to NNW–SSE fault system. The kinematic indicators are consistent with ~NW–SE bulk horizontal extension, similar to the extensional deformation during the later part of the Caledonian orogeny (Silurian to Devonian). At Åkerlandet, adularia-quartz deposition was followed by sphalerite ± galena and finally by precipitation of fluorite and calcite. 40Ar-39Ar thermochronology of a single adularia sample did not yield a well-defined plateau age but the gas released at higher temperatures suggests an early Tonian (980 to 950 Ma) crystallization age, i.e., during the later part of the Sveconorwegian orogeny, although the data do not exclude other less likely interpretations. Previous fluid inclusion microthermometry and geochronological studies and new petrographic and geochemical results suggest that sphalerite ± galena mineralization formed from saline, relatively oxidizing, moderate-temperature, and slightly acidic hydrothermal fluids, either during the Ediacaran or the Middle Ordovician. Metals and H2S were derived from local basement rocks. Based on petrographic evidence, rare earth element composition, and S, C, and O isotope data, fluorite and calcite precipitated under near neutral and relatively reducing conditions. Occurrence of solid bitumen in veins at Åkerlandet and C and O isotope data of calcite at Åkerlandet and in the Laisvall basement veinlets suggest that the precipitation of calcite and fluorite was triggered by interaction of hot and evolved hydrothermal fluids (87Sr/86Sr = 0.718–0.732) with organic matter. Structural, petrographic, and geochemical data at Laisvall suggest that the basement structures hosting calcite-fluorite ± pyrite veinlets were utilized in the Middle Ordovician as the plumbing system for the oxidizing, slightly acidic, metal-bearing brines that caused the economic Pb-Zn mineralization in the overlying sandstones

show abstract

Onsite chelate resin solid-phase extraction of rare earth elements in natural water samples: its implication for studying past redox changes by inorganic geochemistry

et al. 2017

View full text Add to dashboard Cite

Brittle tectonothermal evolution in the Forsmark area, central Fennoscandian Shield, recorded by paragenesis, orientation and 40Ar/39Ar geochronology of fracture minerals

Cited by 38 publications

References 67 publications

Review of the deterministic modelling of deformation zones and fracture domains at the site proposed for a spent nuclear fuel repository, Sweden, and consequences of structural anisotropy

Review of the deterministic modelling of deformation zones and fracture domains at the site proposed for a spent nuclear fuel repository, Sweden, and consequences of structural anisotropy

Polyphase vein mineralization in the Fennoscandian Shield at Åkerlandet, Järvsand, and Laisvall along the erosional front of the Caledonian orogen, Sweden

Onsite chelate resin solid-phase extraction of rare earth elements in natural water samples: its implication for studying past redox changes by inorganic geochemistry

Contact Info

Product

Resources

About