EGU25-7790, updated on 14 Mar 2025
https://doi.org/10.5194/egusphere-egu25-7790
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Insight into the Turonian to Santonian Foraminiferal Biostratigraphy in the Southern Hemisphere 
Ibrahim Hilali, Erik Wolfgring, Anna Waskowska, and Michael Kaminski
Ibrahim Hilali et al.
  • Saudi Aramco, Geological Operations Department , Saudi Arabia (ibrahim.hilali@aramco.com)

 

The majority of micropaleontological observations of Cretaceous successions were conducted on deposits in the Atlantic and Tethyan oceans. However, the southern high-latitude Cretaceous formations remains understudied. During expedition Leg 369 of the International Ocean Discovery Program (IODP), 73 cores were collected from Site 1512 in the Australian Bight, targeting deposits of the Turonian to Santonian interval.

Twenty-nine samples were analyzed using plain polarized light microscope. From each sample, approximately 300 foraminifera specimens were extracted and classified into distinct groups based on their morphological characteristics. These groupings enabled further analysis, which involved sorting the specimens according to taxonomic types. To highlight key distinguishing features, selected taxa were examined using scanning electron microscopy (SEM). A total of fifty-nine taxa were identified, forty-two of which were formally defined at the species level. Species identification depended on established taxonomic frameworks.

Several of the southern-latitude taxa exhibit significant variation in morphology compared to the formerly described planktonic, calcareous, and agglutinated foraminifera from the Northern Hemisphere. Seven newly reported species were identified in the current material: Sculptobaculites sp. 1, Bulbobaculites sp. 1, Bulbobaculites sp. 2, Bulbobaculites sp. 3, Gerochammina sp. 1, Rectogerochammina sp. 1, and Praedorothia sp. 1. In addition, two Turonian biozones defined in the Northern Hemisphere were recognized. The first is planktonic Whiteinella brittonensis foraminiferal biozone consisting of Whiteinella brittonensis, Whiteinella aumalensis, Whiteinella baltica, Muricohedbergella delrioensis, and infrequently observed Planohedbergella prairiehillensis. The second is Bulbobaculites problematicus biozone characterized by agglutinated foraminifera, including Bulbobaculites problematicus, Spiroplectammina navarroana, Eobigenerina variabilis, Textulariopsis rioensis, Textulariopsis texhomensis, and Gerochammina lenis.

The establishment of these biozones provides valuable connections to those in the Northern Hemisphere during the Turonian age. Additionally, this research sheds light on the enigmatic 'Austral Province', a previously understudied region of Late Cretaceous foraminifera. By analyzing the faunal composition, we gain insights into key drivers of foraminifera distribution, including ocean circulation patterns (paleoceanography) and climate conditions (paleoclimate). These findings have significant implications for understanding the dynamics of the Tethys and Atlantic oceans.

 

How to cite: Hilali, I., Wolfgring, E., Waskowska, A., and Kaminski, M.: Insight into the Turonian to Santonian Foraminiferal Biostratigraphy in the Southern Hemisphere , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7790, https://doi.org/10.5194/egusphere-egu25-7790, 2025.