Detrital modes of Carboniferous sandstones reveal the sedimentary budget of convergent plate boundaries during the Variscan s.s. to Paleotethysian orogenic time span (≈420–300Ma) within the Paleo-Mesomediterranean Domain. These sedimentary strata are usually referred to the regional Culm lithostratigraphic depositional unit, and cover an important gap of information to the area located between the Iberian-French massifs and the African Paleo-Atlas, in the western Paleotethys. The studied sandstones belong to the Middle Carboniferous deep-water turbidites of the Almogia and Marbella Conglomerate formations in the Malaguide (Betic Cordillera) and Ghomaride (Rif Chain) Complexes. Here, the sandstone composition is quartzolithic and records an important high-to-medium-low grade metamorphic content in both area (Criniti et al., 2023, 2024), with an increasing trend towards Morocco. The source area was a lithic-transitional recycled orogen with a signature of volcanic and ophiolitic detritus (≈330Ma and/or older). These supplies seem to be derived mainly from a mid-crustal deformed and thrusted terrane prior to the Early Carboniferous, that was involved into the plate convergence south eastwards of the Variscan s.s. orogenic system, rapidly exhumed and uplifted during the mid- Late Carboniferous time. Consequently, a metamorphic basement should be already structured during Middle Carboniferous when thrusting took place, allowing the Culm deposition in the Malaguide and Ghomaride Complexes, suggesting pre-Middle Carboniferous metamorphic highlands. The presence of ophiolitiferous detritus (≈330Ma and/or older) could indicate an obducted oceanic branch, while the synsedimentary volcanic activity (mainly andesitic) should be related to a lost magmatic arc, in good agreement with a nearby subduction area. As a consequence, the thick terrigenous Culm strata could be deposited in a complex foreland basin system 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 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, removing the whole principal source rocks. Criniti S. et al. (2023) - New constraints for the western Paleotethys paleogeography-paleotectonics derived from detrital signatures: Malaguide Carboniferous Culm Cycle (Betic Cordillera, S Spain). Sed. Geol., 458, 106534, https://doi. org/10.1016/j.sedgeo.2023.106534. Criniti S. et al. (2024) - Detrital signatures of the Ghomaride Culm Cycle (Rif Cordillera, N Morocco): new constraints for the northern Gondwana plate tectonics. J. Mar. Pet. Geol., 165, 106861, https://doi.org/10.1016/j.marpetgeo.2024.106861.
Detrital modes of the Culm facies in the Betic-Rifean chain.
Criniti Sara
;
2024-01-01
Abstract
Detrital modes of Carboniferous sandstones reveal the sedimentary budget of convergent plate boundaries during the Variscan s.s. to Paleotethysian orogenic time span (≈420–300Ma) within the Paleo-Mesomediterranean Domain. These sedimentary strata are usually referred to the regional Culm lithostratigraphic depositional unit, and cover an important gap of information to the area located between the Iberian-French massifs and the African Paleo-Atlas, in the western Paleotethys. The studied sandstones belong to the Middle Carboniferous deep-water turbidites of the Almogia and Marbella Conglomerate formations in the Malaguide (Betic Cordillera) and Ghomaride (Rif Chain) Complexes. Here, the sandstone composition is quartzolithic and records an important high-to-medium-low grade metamorphic content in both area (Criniti et al., 2023, 2024), with an increasing trend towards Morocco. The source area was a lithic-transitional recycled orogen with a signature of volcanic and ophiolitic detritus (≈330Ma and/or older). These supplies seem to be derived mainly from a mid-crustal deformed and thrusted terrane prior to the Early Carboniferous, that was involved into the plate convergence south eastwards of the Variscan s.s. orogenic system, rapidly exhumed and uplifted during the mid- Late Carboniferous time. Consequently, a metamorphic basement should be already structured during Middle Carboniferous when thrusting took place, allowing the Culm deposition in the Malaguide and Ghomaride Complexes, suggesting pre-Middle Carboniferous metamorphic highlands. The presence of ophiolitiferous detritus (≈330Ma and/or older) could indicate an obducted oceanic branch, while the synsedimentary volcanic activity (mainly andesitic) should be related to a lost magmatic arc, in good agreement with a nearby subduction area. As a consequence, the thick terrigenous Culm strata could be deposited in a complex foreland basin system 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 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, removing the whole principal source rocks. Criniti S. et al. (2023) - New constraints for the western Paleotethys paleogeography-paleotectonics derived from detrital signatures: Malaguide Carboniferous Culm Cycle (Betic Cordillera, S Spain). Sed. Geol., 458, 106534, https://doi. org/10.1016/j.sedgeo.2023.106534. Criniti S. et al. (2024) - Detrital signatures of the Ghomaride Culm Cycle (Rif Cordillera, N Morocco): new constraints for the northern Gondwana plate tectonics. J. Mar. Pet. Geol., 165, 106861, https://doi.org/10.1016/j.marpetgeo.2024.106861.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
