Datation⁴⁰Ar-³⁹Ar du magmatisme et de filons minéralisés permiens en Provence orientale (France)

Permian continental basins in the Southern Alps (Italy) and peri-mediterranean correlations

“…In particular, it was dominated by intense volcanic activity, which led to some isotopic and geochemical data of vital importance for interregional correlation, and based also on the discovery of a great number of fossiliferous sites (vertebrate footprints, macro-and microfloral assemblages, ostracods) throughout the entire section, allowing some key beds to be fixed, for the purposes of the reliable restoration of Permian regional stratigraphy. Among these are the dating by the 40 Ar-39 Ar method of the A7 Rhyolite to 272.5 ± 03 Ma (Zheng et al 1992), i.e. to a late Early Permian (Kungurian) age, and the attribution of the Les Pradinaux, Le Mitan and Le Muy Fms., as well as the overlying La Motte (or Fabregas) Fm., to the early-mid Middle Permian (Roadian-Wordian: Durand 2006Durand , 2008Gand and Durand 2006;Bourquin et al 2007).…”

Extreme Nd isotope homogeneity in a large rhyolitic province: the Estérel massif, southeast France

“…Whole-rock K-Ar (Roubault et al 1970) and feldspar 39 Ar-40 Ar (Zheng et al 1992) age determinations indicate that most of the Estérel felsic volcanism occurred around 270 Ma. More ages are required to determine whether the Estérel felsic volcanism occurred within a time span compatible with the evolution of a single magmatic body, or over several million years.…”

“…) To demonstrate that the chemical zonations observed from A1 to A11 mirror that of a shallow magma chamber, high-resolution time constraints are required for the Estérel felsic volcanism. Although the available geochronological data suggest that the rhyolite was emplaced over a geologically short time scale (Zheng et al 1992), it is still unclear whether this corresponds to a few million years or a few thousand years. Hence, despite Gondolo's (1989) claims that the rhyolite, at least from A1 to A7, tapped a single magma body on the basis of petrological and geochemical arguments, we cannot exclude the possibility that each rhyolitic sequence (from A1 to A11) actually records a new batch of magma from one, or even several different shallow magma chambers.…”

“…Instead, the abundant mafic rocks inferred at depth from geophysical data (Recq 1972) may represent the initial magmas that generated the rhyolite through fractional crystallization. These mafic rocks may be represented by the sill FC1 (Table 1), one of the few mafic bodies emplaced before or during the felsic volcanism (Zheng et al 1992). Accordingly, the FC1 εNd i value is similar to those of the rhyolite (Table 2).…”

“…Comparable emplacement timesca. 270 Ma for the Estérel (Roubault et al 1970;Zheng et al 1992) and from ca. 285 to 240 Ma for the hypersolvus granites of Corsica (Bonin et al 1972(Bonin et al , 1978Maluski 1976;Poitrasson et al 1995aPoitrasson et al , 1998) -and the observation that Corsica was close to the Estérel shore line during the Permian, before rotation of the Corsica-Sardinia microplate (e.g., Westphal et al 1976), are further evidence for a unique Permian anorogenic magmatic province comprising both Estérel and Corsica.…”