Tracing the detrital Carboniferous Culm signature: correlation of the Algerian Kabylian and the Betic-Rif Belt to constrain the Gondwana tectonics

The Carboniferous Culm deposits of the northern Gondwana continental margin constitute a significant knowledge gap in our understanding of the Paleotethyan tectonic evolution. This study presents novel detrital data of sandstone rocks from the Kabylian Culm in Algeria, providing critical insights. The available coarse sandstones (25 samples) in five representative sections of the Kabylide Domain (Chenoua Massif, Great Kabylia, and Little Kabylia) were sampled. The quartzolithic metamorphiclastic composition indicates the influence of a high-to-low metamorphic grade source. Most of the detritus is moderately sorted, consisting of plutonic-gneissic rock fragments and, suggesting low-to-medium-grade metamorphic lithics. Coeval volcanic activity (andestitic to rhyolitic) is also testified. A significant ophiolite-derived content suggests the existence of a lost oceanic branch. Some samples were determined to be metasediments exhibiting greenschist-facies (<450 °C), linked to the later Paleotethyan tectonic phase. We have found similarities and a few differences in metamorphism, magmatism and ophiolitic suites, when compared with neighboring paleogeographic sectors in the Rif-Betic Chain, belonging to the Paleo-Mesomediterranean Terrane (northern Gondwana). The presence of impure chert detritus probably represents the erosion of a lowermost Carboniferous cherty marker bed, which is absent in Kabylia but present in the Rif-Betic Chain. The Culm cycle in the southern margin of the Paleo-Mesomediterrean Terrane represents the foredeep depozone of the foreland basin of the Culm Cycle. This terrane, together with the Iberian-French massifs, should act as the hinterland. The detrital signatures seem to indicate a lost oceanic closure, subduction, magmatic arc, tectonic stacking, and continental collision, all of which occurred in the northern Gondwana during the Visean Variscan s.s. paleotectonic phase. Southward, the basin transitioned into an oceanic branch of the western Paleotethys. In this context, the Paleo-Saharian-Atlas band constituted the distal passive margin before being deformed by the subsequent Paleotethyan phase that deformed the basin.