Communication Dans Un Congrès Année : 2021

δ18Op geographical variability within the South African Karoo Basin during Permo-Triassic based on tetrapod apatite

Résumé

The Beaufort Group of the Main Karoo Basin of South Africa represents an uninterrupted accumulation of fluvio-lacustrine sediments from the Middle Permian to the Middle Triassic and covers approximately 200000 km², about 20% of the country’s surface area. A diverse vertebrate fauna that includes fish, therapsids, amphibians, archosauromorphs and parareptiles, has been recovered from this rock succession and allows geochemical studies over a large temporal and geographical range. Questions relating to temporal and biological variation of oxygen stable isotope ratios (δ18Op) have been addressed, but geographical variation of the bioapatite-recorded δ18Op has not yet been studied on the Permo-Triassic of South Africa. Here we highlight possible variations in δ18Op recorded on a large-scale basin during the Permo-Triassic. Several tetrapods, mainly therapsids, were sampled from four different biozones, two Permian (Cistecephalus AZ and Dicynodon-Theriognathus AZ) and two Triassic (Lystrosaurus declivis AZ and Trirachodon-Kannemeyeria AZ). For each of these biozones, fossils were sampled from several localities to compare their recorded δ18Op values. While the results showed no variation for both Permian AZ, restricted to the south-western part of the Basin, a north to south decrease of the δ18Op values was noted for both Triassic AZ. Also, a ‘high’ set of values can be separated from a ‘low’ set for each AZ. The lack of variation for the Permian samples may be the result of the sampled localities being in close proximity as well as a unique source for the δ18Op. Triassic latitudinal variation of the δ18Op values results from either a latitudinal gradient of temperature, the continental effect or even the distance from the sources of the watershed or a combination of those. The two set of values suggest two different sources of water, one from the north-east and the other from the south.

BD2021-BookofAbstracts-30.pdf (134.96 Ko) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)
Licence

Dates et versions

hal-04851654 , version 1 (02-01-2025)

Identifiants

  • HAL Id : hal-04851654 , version 1

Citer

Kévin Rey, Romain Amiot, François Fourel, Julie Luyt, Frédéric Fluteau, et al.. δ18Op geographical variability within the South African Karoo Basin during Permo-Triassic based on tetrapod apatite. 9th International Bone Diagenesis Meeting, Sep 2021, Evora, Portugal. ⟨hal-04851654⟩
128 Consultations
22 Téléchargements

Partager

  • More