Carboniferous Culm correlation of the Algerian Kabylian and the Betic-Rif Belt

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.

Synthetic column of the Paleozoic succession in the Kabylides.

cite as: Criniti, S., Talmat, S., Martín-Martín, M. and Critelli, S. (2026): Tracing the detrital Carboniferous Culm signature: correlation of the Algerian Kabylian and the Betic-Rif Belt to constrain the Gondwana tectonics. Journal of African Earth Sciences, Volume 241, 106194. https://doi.org/10.1016/j.jafrearsci.2026.106194

Alicante University geology students visit Ojos Negros quarry

Students of the third course of Geology of the Alicante University within the subject of Regional Geology: visit the abandon Ojos Negros quarry. This is an excellent Ordovician-Silurian section of the Hirnantian glaciation.

The picture shows the student at the quarry border.

Ojos Negros quarry

Malaguide Carboniferous culm cycle in the Betic Cordillera

Carboniferous sandstone within the Paleo-Mesomediterranean Domain (Malaguide Subdomain), in southern Spain, represents a key detrital mode within the sedimentary budget of convergent plate boundaries during the Variscan s.s. to Paleotethysian orogenic time span (≈420–300 Ma). This Carboniferous detritus corresponds with Culm lithostratigraphic depositional unit, and it covers an important gap of information (paleogeographic, paleotectonic, source areas) to the area located between the Iberian-French massifs and the African Paleo-Atlas, in the western Paleotethys. Sandstone composition is quartzolithic and records an important high-to-medium-low grade metamorphic content. The source area was a lithic and transitional recycled orogen with a signature of volcanic and ophiolitic detritus (≈330 Ma and/or older). These supplies seem to be derived from a mid-crustal deformed and thrusted pre-late Ordovician to Early Carboniferous terrane, involved in the plate convergence (the southern Europe Iberian-French massifs overriding the north African area) southeatwards of the Variscan s.s. orogenic system, rapidly exhumed and uplifted at mid-Late Carboniferoous time. Consequently, in the overriding hinterland (southern Europe: Iberian-French massifs), metamorphic basement should be already structured during middle Carboniferous when thrusting took place and deposition of Culm facies started in the Malaguide Complex, suggesting Proterozoic-Early Carboniferous (most probably, ≈420 to 330 Ma) metamorphic highlands. The presence of serpentinite-like detritus (≈330 Ma and/or older) seems to indicate a metamorphosed oceanic crust being dismantled at that time. Thus, sources from ophiolitic suture (most probably developed at ≈420–330 Ma) zones are tentatively proposed in other northern Gondwana of southwestern Europe. The occurrence of a synsedimentary volcanic activity (andesitic) should be related to a lost magmatic arc (most probably developed at ≈360–330 Ma), reinforcing the idea of a nearby subduction area. Therefore, the thick terrigenous Culm deposits (≈330–300 Ma) from the Malaguide Subdomain could be deposited in a complex foreland system basin connected northward with carbonate platforms and with a crystalline highland uplifted domain from the southern Europe Iberian-French massifs and southward with the African Paleo-Atlas Domain. The studied mid- to late Carboniferous sandstone petrofacies deeply contributes to paleogeographic reconstructions since block fragmentation and spreading, during the Paleotethysian and Alpine orogenies, rearranged the Paleozoic paleogeography now part of the Cenozoic Perimediterranean Chains. After the correlation with the Carboniferous from other western Paleotethys domains, new paleogeographic-paleotectonic constraints.

Paleogeographic-paleotectonic maps: A) global pre-Pangea situation (350 Ma, Early Carboniferous); B) global Pangea situation (310 Ma, Late Carboniferous); C) detail of the Pangea situation (310 Ma, Late Carboniferous) in the northern Gondwana area; D) nowadays situation; E) geological cross-section at 310 Ma,Late Carboniferous (located in Fig. 14C). A) and B) modified from Pérez-Estaún et al. (2004) and Vera (2004), C) modified from Arenas et al. (2016), D) modified from Vera (2004). In C appears the location of the studied sectors (1–4) in the Malaguide Subdomain from the Paleo-Mesomediterranean Domain, and the corelated sectors: Iberian (sectors 5–7) and Central French (sectors 8 and 9) Massifs, E Paleo-Mesomediterranean Domain (sector 10), Bohemian Massif (sector 11), Paleo- Atlas-Saharian Domain (sectors 12–14), and Arabian (sector 15)

Paleogeographic-paleotectonic maps: A) global pre-Pangea situation (350 Ma, Early Carboniferous); B) global Pangea situation (310 Ma, Late Carboniferous); C) detail of the Pangea situation (310 Ma, Late Carboniferous) in the northern Gondwana area; D) nowadays situation; E) geological cross-section at 310 Ma, Late Carboniferous (located in Fig. 14C). A) and B) modified from Pérez-Estaún et al. (2004) and Vera (2004), C) modified from Arenas et al. (2016), D) modified from Vera (2004). In C appears the location of the studied sectors (1–4) in the Malaguide Subdomain from the Paleo-Mesomediterranean Domain, and the corelated sectors: Iberian (sectors 5–7) and Central French (sectors 8 and 9) Massifs, E Paleo-Mesomediterranean Domain (sector 10), Bohemian Massif (sector 11), Paleo- Atlas-Saharian Domain (sectors 12–14), and Arabian (sector 15).

cite as: Criniti, S.; Martín-Martín, M.; Martín-Algarra, A. New Constraints for the Western Paleotethys Paleogeography-Paleotectonics Derived from Detrital Signatures: Malaguide Carboniferous Culm Cycle (Betic Cordillera, S Spain). Sediment. Geol. 2023, 458, 106534, doi: 10.1016/j.sedgeo.2023.106534.

 

Regional geology field trip to Teruel

Students of the third course of Geology of the Alicante University within the subject of Regional Geology: visit Jarafuel triassic section, Aguaton jurassic section, Murero paleontological site, Fombuena section, Santa Cruz Paleozoic Seas Museum, Ojos Negros Mine, and Orea-Checa road Hirnatian section.

Student in the Aguatón “tunnel” section

The visit took place from 16 to 19 October of 2019 and the professors in charge were Juan Alberto Pérez-Valera and José Enrique Tent-Manclús.

Zoophycos found in the Devonian Santa Cruz de Nogueras Formation, near the village of Santa Cruz de Nogueras. The specimen is now in the Paleozoic Seas Museum.