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Palaeocene faulting in SE Sweden from U–Pb dating of slickenfibre calcite
Author(s) -
Goodfellow Bradley W.,
Viola Giulio,
Bingen Bernard,
Nuriel Perach,
KylanderClark Andrew R.C.
Publication year - 2017
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12280
Subject(s) - calcite , geology , tectonics , fault (geology) , shear (geology) , mineralogy , geochemistry , slip (aerodynamics) , seismology , paleontology , physics , thermodynamics
Estimating the timing of faulting is crucial to modelling tectonics, palaeoseismicity, landscape evolution and fault mechanics. Four slickenfibre calcite samples from a conjugate strike‐slip fault set in a platformal limestone, SE Sweden, were dated using U–Pb. Three of the samples yielded an average age of 64.8 ± 6.5 Ma, while the fourth yielded a marginally younger age of 54.7 ± 5.5 Ma. Precipitation of the fibres is interpreted as syn‐deformational. Age uncertainty and dispersion reflect incorporation of common Pb and tiny host‐rock components into the dated calcite and/or possible fault reactivation through ca. 55 Ma. We infer from crystal characteristics, stable isotopes (δ 18 O and δ 13 C) and rare‐earth elements that fibres formed in an environment rich in deep‐seated fluids, at temperatures of 40–200°C, with shear stresses exceeding 10 MP a and at a maximum burial depth of c. 4 km. This Palaeocene faulting may reflect far‐field stresses from shortening in the Alps.