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 (d18O and d13C) 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 MPa and at a maximum burial depth of c. 4 km. This Palaeocene faulting may reflect far-field stresses from shortening in the Alps.
Palaeocene faulting in SE Sweden from U–Pb dating of slickenfibre calcite / Bradley W. Goodfellow; Giulio Viola; Bernard Bingen; Perach Nuriel; Andrew R.C. Kylander-Clark. - In: TERRA NOVA. - ISSN 0954-4879. - STAMPA. - 29:5(2017), pp. 321-328. [10.1111/ter.12280]
Palaeocene faulting in SE Sweden from U–Pb dating of slickenfibre calcite
VIOLA, GIULIO;
2017
Abstract
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 (d18O and d13C) 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 MPa and at a maximum burial depth of c. 4 km. This Palaeocene faulting may reflect far-field stresses from shortening in the Alps.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.