Provenance of Palaeozoic sandstones from the Carnic Alps (Austria): petrographic and geochemical indicators

Abstract

An integrated approach of petrographic analysis, whole rock geochemistry and microprobe analysis has been applied to obtain information on the geodynamic development and the provenance for Ordovician to Permian siliciclastic successions exposed within the Carnic Alps (Austria). Sandstone detrital mode and geochemical results refine previous geodynamic interpretations. Late Ordovician samples indicate a stable craton and recycled orogenic and, possible, extensional setting. The Early Carboniferous is interpreted to represent a compressional environment, followed by a Late Carboniferous molassetype foreland basin, and a Permian extensional geodynamic setting. Contrasting geochemical patterns of postVariscan and Permian sequences suggest a rift setting. Electron microprobe data of detrital white mica also indicate changes in the provenance. Compositional data reflect a shift from low-to medium-grade metamorphic (Ordovician) to high-grade metamorphic (Carboniferous) to low-to medium-grade metamorphic and plutonic source rocks (Permian). Additionally, our data show that various chemical discrimination diagrams do not include all possible ranges of sandstones, and that high contents of detrital mica and ultra-stable heavy minerals may cause misclassification. Consequently, we propose the use of multi-method approach for provenance studies, including the control of geochemical data by modal analysis and heavy mineral investigations.

Birth and evolution of the Paleocarnic Chain in the Southern Alps: a review

“…It is likely that further north, a number of parallel systems of wrench faults were active in the same way as is suggested here. Sonntag et al (1997), Mader and Neubauer (2004), Mader et al (2007), and Neubauer et al (2007), based on the study of detrital white micas from Mississippian synorogenic sandstones, propose a classic frontal convergence setting, marked by a compressional accretionary wedge and a related flexural basin associated with a peripheral bulge, whose occurrence might be confirmed by shallow-water deposits.…”

Tectonic Evolution of the Proto‒Tethys in the Early Devonian: Insights From the Turbidite in the North Qilian Belt, NW China

“…The composition of clastic sedimentary rocks have been widely used to imply the depositional tectonic setting (Bhatia, 1985; Bhatia & Crook, 1986; Floyd et al., 1991; Guo et al., 2012; Mader & Neubauer, 2004; Taylor & McLennan, 1985; Yan et al., 2016). On the SiO 2 /Al 2 O 3 versus K 2 O/Na 2 O tectonic discrimination diagram, the sandstone samples from the Jiayuguan mélange plot within an evolved arc setting (A1) and an arc setting (A2) with a supply of felsic‒plutonic, basaltic and andesitic detritus (Figure 10a), which is in accordance with their petrology.…”

“…It exists widely in orogenic belts and also mingles with the basalt and/or limestone blocks of seamounts that are incorporated into accretionary complexes during the process of ocean subduction. The ages and provenances of the turbidites in an accretionary complex record the tectonic evolution of the subduction zone (Fergusson & Coney, 1992; Floyd & Leveridge, 1987; Mader & Neubauer, 2004; Maynard et al., 1982; Yan et al., 2016, 2021). Voluminous early Paleozoic turbidites and blocks of high pressure/low temperature (HP/LT) metamorphic rocks, seamount‒related basalts and limestones, and ophiolites occur in the North Qilian belt as subduction related accretionary complexes (S. Song et al., 2013; Xiao et al., 2009; Yan et al., 2021; Zhang et al., 2015).…”

Petrology and geochemistry of greywackes of the ~1.6 Ga Middle Aravalli Supergroup, northwest India: evidence for active margin processes

“…The major and trace element compositions of sediments have been widely used to infer the plate tectonic setting of ancient sedimentary basins (Bhatia and Crook 1986;Roser and Korsch 1986;Mader and Neubauer 2004;Verma and Armstrong-Altrin 2013). But such an approach has been contested by some researchers (e.g.…”