Coniacian – Maastrichtian calcareous nannofossil biostratigraphy and carbon-isotope stratigraphy in the Zagros Basin (Iran): consequences for the correlation of Late Cretaceous Stage Boundaries between the Tethyan and Boreal realms
Razmjooei, Mohammad Javad; Thibault, Nicolas; Kani, Anoshiravan; Mahanipour, Azam; Boussaha, Myriam; Korte, Christoph
Newsletters on Stratigraphy Volume 47 Number 2 (2014), p. 183 - 209
published: Jun 1, 2014
ArtNo. ESP026004702002, Price: 29.00 €
Calcareous nannofossil biostratigraphy and stable isotope stratigraphy have been investigated in the Shahneshin section of the Gurpi Formation from the Zagros Basin (Iran). The results show that the Gurpi Formation spans the late early Coniacian to late Thanetian. The age-model shows that the Shahneshin section spans the Coniacian to mid-Campanian with a good continuity whereas condensation is highlighted in the late Campanian, across the Campanian/Maastrichtian boundary and in the late Maastrichtian. Extreme condensation is recorded after the Cretaceous-Paleogene boundary with the complete absence of the Danian, and the Selandian and lower Thanetian being comprised in only 6 m at the top of the Gurpi Formation. Correlation of the carbon-isotope profile with other reference curves allows the recognition of several Late Cretaceous excursions at the Shahneshin section such as the Beeding, White Fall, Kingsdown, Michel Dean, Haven Brow, Horseshoe Bay, Buckle, Hawks Brow, Santonian/Campanian boundary (SCBE) and Campanian/Maastrichtian boundary (CMBE) events. Correlation to a recently proposed global δ13C stack for the Late Cretaceous points to a major mismatch of this compilation with magnetostratigraphy in the Santonian – early Campanian interval. The δ13C correlation, supported by calcareous nannofossil biostratigraphy, brings insights into: (1) the position of the Coniacian/Santonian, Santonian/Campanian and Campanian/Maastrichtian boundaries with respect to carbon-isotope stratigraphy and calcareous nannofossil bio-horizons, and (2) their correlation between the Tethyan and Boreal realms.