Nova Terra 52

&KDSWHU 468 International Journal of Earth Sciences (2021) 110:467–485 13 Introduction The Variscan Orogen resulted from the Paleozoic con- vergence between Gondwana and Laurussia that culmi- nated with the assembly of Pangea (Matte 2001; Arenas et al. 2016a; Díez Fernández et al. 2016). This orogen, which extends throughout central and western Europe, in parts of north and northwest of Morocco as well as in the Appalachian Mountains of northeastern America, contains the suture of the Rheic Ocean, other minor sutures, and sections of the thinned paleomargin of Gondwana, which hosted a long-lived (Avalonian–Cadomian) active mag- matic arc (Dalziel 1997; Fuenlabrada et al. 2010; Pereira et al. 2012a, b; Albert et al. 2015; Andonaegui et al. 2016). Variscan deformation is penetrative and strong along the orogen, and Alpine overprinting affected some areas. Yet, the Bohemian Massif in Germany, the Central and Armorican massifs in France and Iberian Massif in Iberian peninsula (Fig. 1), contain well-preserved low-strain and low-grade Neoproterozoic to Early Paleozoic sedimentary series (Linnemann et al. 2000; Fernández-Suárez et al. 2002; Murphy et al. 2002; Pereira 2015). The correlation between the sedimentary series of these nowadays distant massifs, as well as improving the knowledge of the pri- mary location of the paleobasins along the (North African) Gondwana margin, are being actively investigated through the study of paleofauna provinces and stratigraphic record, as well as provenance studies. It is widely accepted that the Late Paleozoic Gond- wana–Laurussia interplay produced a complex dismember- ing and juxtaposition of terranes as a result of their pro- gressive collision. From a paleogeographic point of view, adjoining sections of the Gondwana margin dispersed along the Variscan Orogen should have an analogous sedimentary record between Late Ediacaran and Early Cambrian times. However, the common azoic nature of many of these series and the complex deformation associated with Variscan tec- tonics, make it difficult to recognize the primary configura- tion of the sedimentary series and to establish correlations between them. For this reason, valuable information can be obtained from whole-rock major and trace element and Nd isotopic geochemistry, combined with U–Pb radiometric ages and Hf systematics of detrital zircon (Fernández-Suárez et al. 2002; Linnemann and Romer 2002; Pereira et al. 2006, 2015; Linnemann et al. 2008; Fuenlabrada et al. 2020). The Sm–Nd isotopic geochemistry of siliciclastic rocks provides an excellent approach to the average composition, provenance and isotopic sources of the materials which form the upper continental crust (McLennan et al. 1990; McLennan and Hemming 1992). In provenance studies, siliciclastic rocks may provide more significant informa- tion than the associated igneous rocks (granitoids), since the juvenile material that may be involved in the genera- tion of many igneous rocks can be mixed with older initial Fig. 1 Zonation of the European Variscan Orogen (Díez Fernández and Arenas 2015). Based on Franke (1989), and Martínez Catalán (2011). Location of Figs. 2 and 3 is shown