Detrital zircon <scp>U–Pb–Hf</scp> data from Cambrian sandstones of the Ougarta Mountains Algeria: Implication for palaeoenvironment

We report new detrital zircon U–Pb ages and Hf isotopic signatures of detrital zircons in Cambrian sedimentary rocks from the Ougarta Mountains of Algeria in the West African Craton (WAC) in order to provide constraints on the palaeo‐catchments of the Early Palaeozoic river systems draining Gondwana. The Cambrian sedimentary samples from the Ougarta Mountains have near‐identical age spectra with a dominant age peak at 618 Ma and an additional age peak at 2,035 Ma. The oldest detrital zircon grain is 3,407 Ma. The εHf (t) values of the 618 Ma age peak spans from εHf (t) +12 to −25 with a dominant mode at −1; the εHf (t) of the Palaeoproterozoic zircon ranges from 6 to −27 with an average of −10; the pre‐2,300 Ma zircon Hf lie along a crustal evolution trajectory ( 176 Lu/ 177 Hf = 0.01) back to the depleted mantle at ~3,100 Ma. The maximum depositional age of the sandstones in the Sebkhet el Melah Formation is constrained by the youngest detrital zircon age of 559 ± 13 Ma and by the underlying volcaniclastic rocks dated at 555 ± 7 Ma (Late Ediacaran to the Early Cambrian). The 618 and 2,035 Ma age peaks are consistent with a proximal provenance from the WAC, and it is possible that recycling of eroded material from the Cadomian arc and Pan‐African rocks may have been a potential source of the Ediacaran detrital zircons analysed herein. There were four (0.9%) Stenian detrital zircons identified in this study, and our results are consistent with the lack of WAC Stenian detrital zircon noted in previous studies, except those reported from a single Middle Cambrian sample in Morocco. Correlative sedimentary successions further to the east contain ubiquitous ca. 1.0 Ga detrital zircon that was likely supplied from the Trans‐Gondwana Mountain chain. It is noteworthy that the WAC and Sahara Metacraton are surrounded on three sides by Neoproterozoic orogenic systems, with the Rokelide, Dahomeyide, Pharuside, Anti‐Atlas, and Brasiliano orogens (reconstructed position from Gondwana palaeogeography) around the WAC and the Dahomeyide, Pharuside, East African orogen, and Oubangides orogens around the Sahara Metacraton. We posit these orogenic belts acted as drainage divides that controlled sediment routing pathways. Additionally, the occurrence of Stenian detrital zircon in Morocco could be explained by longshore drift coming from the east (present‐day coordinates).

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.