The significance of Benthic Foraminiferal Deep-Sea Drilling data in the Cretaceous Austral Realm

Benthic foraminiferal studies from the Cretaceous of Australia provide critical insights into paleoenvironmental and biostratigraphic correlations across the Southern Hemisphere. This study contextualizes data from International Ocean Discovery Programme (IODP) Sites U1512, U1513, U1514 and U1516 , and significant data from other sources. We present the significance of calcareous and agglutinated benthic foraminiferal data for our understanding of palaeoenvironmental dynamics in the mid- to Upper Cretaceous sediments of the southern hemisphere, relying on complementary data from planktonic foraminifera as well as calcareous nannofossils.
In the Albian, the benthic foraminiferal record at Site U1513 illustrates transitions from neritic to upper bathyal environments, initially marked by the dominance of agglutinated taxa such as Ammodiscus and Haplophragmoides. The shift to calcareous benthic foraminifera, including the markers Gavelinella intermedia and Osangularia schloenbachi, reflects increasing marine influence. These assemblages correlate with records from the Kerguelen Plateau, the Great Artesian Basin, and South America, providing a coherent framework for Southern Hemisphere biostratigraphy during the Albian.
The Cenomanian-Turonian interval captures the impact of Oceanic Anoxic Event 2 (OAE 2). At Sites U1513, U1516, and U1512, a reduced diversity in calcareous benthic foraminifera and the increased dominance of agglutinated taxa highlights the environmental stress linked to dysoxic conditions. These changes are mirrored across the Southern Hemisphere, with parallels in South Africa and Walvis Ridge.
The Coniacian and Santonian successions at Site U1513 document stable bathyal environments dominated by calcareous benthic taxa such as Gavelinella berthelini and Notoplanulina rakauroana. These assemblages exhibit remarkable correlations with other Southern Hemisphere records, including the Falkland Plateau and New Zealand. This synthesis underscores the significance of calcareous and agglutinated benthic foraminifera for correlations through the Southern Hemisphere and helps to improve our understanding of the interplay between local and global paleoenvironmental dynamics, and oceanographic and climatic developments during the Cretaceous.