First report of a Middle-Upper Permian magmatism in the SE Iberian Ranges: characterisation and comparison with coeval magmatisms in the western Tethys

Abstract

A multiple basic to intermediate sill is reported for the first time in the south-eastern Iberian Ranges. It is composed of several tabular to irregular levels intercalated within the fluvial sediments of the Alcotas Formation (Middle-Upper Permian). The sill could represent the youngest Paleozoic subvolcanic intrusion in the Iberian Ranges.The igneous rocks are classified as basaltic andesites. They show a subophitic microstructure constituted by plagioclase (An62 -An6), augite (En48Wo44Fs7 -En46Wo39Fs15), pseudomorphosed olivine, minor amounts of oxides (magnetite and ilmenite) and accessory F-apatite. According to the mineralogy and whole-rock composition, their geochemical affinity is transitional from subalkaline to alkaline.Radiometric dating of the sill is not feasible due to its significant alteration. Field criteria, however, suggest an emplacement coeval to the deposition of the Alcotas Formation (Middle-Upper Permian). This hypothesis is supported by the transitional affinity of these rocks, similar to other Middle-Upper Permian magmatisms in the western Tethys, e.g., from the Pyrenees.Taking into account their isotopic signature (ε Sr : -6.8 to -9.2; ε Nd : +1.7 to +8.3), an enriched mantle source with the involvement of a HIMU component has been identified. This interpretation is supported by the trace element contents.

Protracted volcanism after large impacts: Evidence from the Sudbury impact basin

“…The contacts with the fragmental units of the Onaping Formation are irregular, although overall, aphanitic intrusions tend to form relatively tabular, dyke‐ or sill‐like bodies. The irregular margins are wavy and characterized by millimeter to meter size undulations which can be considered “billows” [ Befus et al ., ; Lago et al ., ]. Where the margins are disrupted, they generate millimeter to meter size globules of vitric material dispersed into the host Onaping Formation.…”

“…Aphanitic intrusions in the Onaping Formation can be considered coeval with the deposition of the breccias and tuffs given their wavy, billowed margins that often transition into peperite (Figure ) and globules of vitric material intermixing with the Onaping Formation. These relations are normally found where magma has come in contact with water‐saturated, unconsolidated sediments [ Kokelaar , ; White et al ., ; Hooten and Ort , ; Skilling et al ., ; Befus et al ., ; Lago et al ., ; Cas and Giordano , ]. Hence, field relationships between aphanitic intrusions and host rocks provide evidence of syndepositional intrusion of magma into wet and not fully consolidated breccias and tuffs throughout the Onaping Formation.…”

Sources of Sr and S In Aluminum-Phosphate-Sulfate Minerals In Early-Middle Triassic Sandstones (Iberian Ranges, Spain) and Paleoenvironmental Implications for the West Tethys

“…At the end of the Variscan Orogeny, the early stages of the breakup of Pangea resulted in the formation of new rift systems, such as the Iberian, Pyrenean, and Catalonian basins in the Iberian plate (Fig. 2;López-Gó mez and Arche 1993a;De Vicente et al 2009;Vargas et al 2009;Lago et al 2012).…”

The enriched Variscan lithosphere of NE Iberia: data from postcollisional Permian calc-alkaline lamprophyre dykes of Les Guilleries

“…In spite of the similarities, significant variations among LGL dykes show up for mobile elements and the highest differences occur for F, Ba, Sr, Cr, Zn, Ni, Rb, Pb and Cs concentrations. 1994) and the south-eastern Iberian Ranges (Lago et al, 2004;Lago et al, 2012). Variscan spessartites, kersantites and minettes from the inner parts of the Variscan Belt are from: minettes, kersantites and spessartites from Vosges, Schwarzwald and Black Forest, Soder (2017); kersantites and spessartites from Erzgebirge in Bohemian massif, Seifert (2008); lamproites from Bohemian massif, Krmíček et al (2015).…”

“…D) Zr/TiO 2 vs. Nb/Y diagram (afterWinchester and Floyd (1977)) in which LGL dykes plot in the fields of andesite to sub-alkaline basalt. Data sources: Aiguablava spessartites,Enrique (2009) andUbide et al (2010); Cretaceous camptonites from the Catalan Coastal Ranges (CCR),Ubide (2013); camptonites from the Spanish Central System,Orejana et al (2008); spessartites from Maladeta (Pyrenees),Perini et al (2004); high-K basaltic andesite dykes from Sarrabus (Sardinia),Ronca et al (1999); Permian volcanic calc-alkaline andesites and alkaline basalts from eastern Pyrenees (Serra del Cadí,Innocent et al, 1994) and the south-eastern Iberian Ranges(Lago et al, 2004;Lago et al, 2012). Variscan spessartites, kersantites and minettes from the inner parts of the Variscan Belt are from: minettes, kersantites and spessartites from Vosges, Schwarzwald and Black Forest, Soder (2017); kersantites and spessartites from Erzgebirge in Bohemian massif,Seifert (2008); lamproites from Bohemian massif,Krmíček et al (2015).…”