Stratigraphy of the Cretaceous/Paleogene boundary interval at the Lord Howe Rise, Southwest Pacific

Created 17/10/2025

Updated 17/10/2025

During Deep Sea Drilling Project (DSDP) Leg 21, Cenozoic and latest Cretaceous sediments were recovered at Site 208 on the Lord Howe Rise, Southwest Pacific. We provide new biostratigraphic, magnetostratigraphic and geochemical data of cores from Site 208 to constrain stratigraphy around the Cretaceous/Paleogene (K/Pg) boundary. Biostratigraphic data on calcareous nannofossils indicate a nearly continuous deposition of sediment from the Maastrichtian of the Late Cretaceous to the Danian and Selandian of the Paleocene at depths of 540-590 meters below seafloor (mbsf). The biostratigraphic data suggest that the K/Pg boundary corresponds to a siliceous claystone at the bottom of an interval of silicified sediment at the depths of 576.0-576.8 mbsf. Carbonate carbon isotopic composition (δ13Ccarb) reveals a negative shift across this interval, which is consistent with the global pattern of δ13C across the K/Pg boundary. Osmium concentration and Os isotopic composition (187Os/188Os) are used for identification of the K/Pg boundary, as the K/Pg boundary is marked by a peak in Os concentration and a drop in 187Os/188Os values to 0.12-0.15 caused by the K/Pg bolide impact. Our 187Os/188Os data indicate a similar variation with that of the coeval ocean water, with the lowest 187Os/188Os value of 0.12-0.16 in the siliceous claystone. However, the concentration of Os is low (<80 pg g-1) in this sample. This suggests that the siliceous claystone was deposited around the K/Pg boundary, but may not include the boundary itself. This study has revealed that while the sedimentary record across the K/Pg boundary interval at Site 208 may not be completely continuous, it nevertheless captures a time interval that is close to the K/Pg bolide impact. Citation: Junichiro Kuroda, Kyoko Hagino, Yoichi Usui, Paul R. Bown, Kan-Hsi Hsiung, Saburo Sakai, Ron Hackney, Saneatsu Saito, Masafumi Murayama, Takuto Ando, Naohiko Ohkouchi; Stratigraphy around the Cretaceous-Paleogene boundary in sediment cores from the Lord Howe Rise, Southwest Pacific. GSA Bulletin 2021;; 134 (5-6): 1603–1613. doi: https://doi.org/10.1130/B36112.1

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Title Stratigraphy of the Cretaceous/Paleogene boundary interval at the Lord Howe Rise, Southwest Pacific
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/6b5c8776-62c7-4642-a26d-e1862d871ab4
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Geoscience Australia Data
clientservices@ga.gov.au
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Geospatial Coverage
Map data © OpenStreetMap contributors
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This dataset was originally found on Geoscience Australia "Stratigraphy of the Cretaceous/Paleogene boundary interval at the Lord Howe Rise, Southwest Pacific". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/stratigraphy-of-the-cretaceous-paleogene-boundary-interval-at-the-lord-howe-rise-southwest-paci