Late Cretaceous stratigraphy and paleoceanographic evolution in the Great Australian Bight Basin based on results from IODP Site U1512

Authors

K. G. MacLeod, University of MissouriFollow
Lloyd T. White, University of Wollongong, AustraliaFollow
Carmine C. Wainman, University of Adelaide, AustraliaFollow
Mathieu Martinez, University of Rennes, France.Follow
Matthew M. Jones, University of MichiganFollow
Sietske J. Batenburg, Géosciences Rennes, FranceFollow
Laurent Riquier, Sorbonne Université, FranceFollow
Shannon J. Haynes, Princeton UniversityFollow
David K. Watkins, University of Nebraska at LincolnFollow
K. A. Bogus, University of Exeter, UKFollow
H.-J. Brumsack, University of Oldenburg, GermanyFollow
R. do Monte Guerra, Unisinos University, BrazilFollow
Kirsty M. Edgar, University of Birmingham, UKFollow
Trine Edvardsen, University of Exeter, UKFollow
Dennis Harry, Colorado State UniversityFollow
Takashi Hasegawa, Kanazawa University, JapanFollow
R. W. Hobbs, Durham University, UKFollow
Brian T. Huber, Smithsonian InstitutionFollow
T. Jiang, China University of Geosciences in Wuhan, ChinaFollow
J. Kuroda, University of Tokyo, Japan,Follow
E. Y. Lee, Chonnam National University, South KoreaFollow
Yong-Xiang Li, Nanjing University, ChinaFollow
Alessandro Maritatai, University of Tasmania, AustraliaFollow
Lauren K. O'Connor, University of ArizonaFollow
Maria Rose Petrizzo, University of Milan, ItalyFollow
Tracy M. Quan, Oklahoma State UniversityFollow
C. Richter, University of Louisiana at LafayetteFollow
Maria Luisa Garcia Tejada, Japan Agency for Marine-Earth Science and TechnologyFollow
G. Tagliaro, University of Texas at AustinFollow
Erik Wolfgring, University of Vienna, AustriaFollow
Zhaokai Xu, Institute of Oceanology, Chinese Academy of SciencesFollow

Date of this Version

2-25-2020

Citation

Published in Gondwana Research 83 (2020), pp 80–95.

DOI: 10.1016/j.gr.2020.01.009

Comments

Copyright © 2020 International Association for Gondwana Research. Published by Elsevier B.V. Used by permission.

Abstract

The Upper Cretaceous sedimentary sequence at International Ocean Discovery Program Site U1512 in the Ceduna Sub-basin of the Great Australian Bight represents a continuous, N 690 m thick interval of black silty clay and claystone spanning the lower Turonian through Lower Campanian (~10 million years). Sediments were deposited in an elongate, ~E-W oriented, ~2500 km long rift system that developed between Australia and Antarctica with an open-ocean connection to the west and a continental bridge to the east. Site U1512 cores provide a unique, continuous record of Late Cretaceous deposition in the Ceduna Sub-basin on the hanging wall of the Wallaroo Fault Zone. Study of U1512 samples could provide both an important high-latitude, southern hemisphere perspective on climatic evolution during the peak and demise of the Cretaceous hothouse and an offshore record of the sedimentation history in the basin during the Late Cretaceous portion of the Gondwanan breakup.

The Upper Cretaceous sequence at Site U1512 is notable for its lithologic uniformity. Burrow-mottled to massive claystone and silty claystone make up the majority of the almost 700 m section, while rare (n = 28) isolated, 2 to 21 cm thick medium to fine sandstone beds are a minor lithology. Macrofossils present include common inoceramids and rare occurrences of other bivalves and ammonites. Microfossils include common occurrences of calcareous nannofossils, agglutinated and calcareous benthic foraminifera, radiolaria and organic-walled dinoflagellate cysts as well as rare, small, surface dwelling planktonic foraminifera. Carbonate (<7%) and organic carbon (<1.5%) contents are low. Despite the lithologic uniformity, rhythmic alternations in the intensity of magnetic susceptibility and natural gamma radiation are well-resolved in much of the recovered section and continue through minor coring gaps (as documented by downhole logs). Data from Site U1512 provide new perspectives on the deep-water frontier region between Antarctica and Australia.