High southern latitude record of Cretaceous ocean anoxic event (OAE) in the Hikurangi Plateau (Southwest Pacific)

Author(s): Woodhouse, Adam D.; Malié, Pierre; Crundwell, Martin P.; Shepherd, Claire L.; Rabinowitz, Hannah S.; Hollis, Chris; Aze, Tracy L.; Wallace, Laura; Saffer, Demian; Pecher, Ingo; Barnes, Philip M.; Petronotis, Katerina; LeVay, Leah J.
Author Affiliation(s): Primary:
University of Leeds, School of Earth and Environment, Leeds, United Kingdom
Other:
University of Montpellier, France
GNS Science, New Zealand
Brown University, United States
Pennsylvania State University, United States
University of Auckland, New Zealand
National Institute of Water and Atmospheric Research, New Zealand
Texas A&M University, United States
Volume Title: Geological Society of America, 2018 annual meeting & exposition
Source: Abstracts with Programs - Geological Society of America, 50(6); Geological Society of America, 2018 annual meeting & exposition, Indianapolis, IN, Nov. 4-7, 2018. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Deep-sea records of Ocean Anoxic Events (OAEs) are relatively rare, especially within the high southern latitudes. Consequently, their occurrence is valuable to our interpretation of the paleoceanographic evolution of our planet during global climatic shifts due to their heightened sensitivity to seawater chemical and temperature perturbations. During International Ocean Discovery Program (IODP) Expedition 375, Site U1520 penetrated the sedimentary cover of the incoming Pacific Plate on the Hikurangi Subduction Margin (HSM) to 1045.75 mbsf. Included in this record are ∼30 m (15.45 m recovered) of dark gray clayey siltstones and organic-rich mudstones interbedded with volcanoclastic conglomerates of late Cenomanian-early Turonian age. Shipboard investigation of these lithologies revealed heightened Total Organic Carbon (TOC) values varying from ∼4-14%. Our evidence infers that the section preserved at this site records the first occurrence of OAE2 within the HSM, illustrating the environmental perturbations through an OAE from a high southern paleolatitude (∼70-80° S) site proximal to the Cretaceous Antarctic mainland. We investigated the foraminiferal, calcareous nannofossil, radiolarian and geochemical record preserved within the HSM to document the environmental stresses and paleoceanographic mechanisms driving the observed shifts of the microfossil communities within this high-southern latitude marine setting. Foraminifer assemblage analyses reveal variably preserved populations of rare foraminifers, suggesting fluctuating environmental conditions recorded throughout the section. Planktonic foraminiferal diversity and abundance remains relatively low, composed primarily of muricohedbergellids. As well as TOC and faunal analysis, this investigation details high resolution benthic foraminiferal, and bulk isotopic analysis (δ18O and δ13C) through the OAE, detailing the localised environmental perturbations and their relationship with similar high latitude sites.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Anaerobic environment; Assemblages; C-13/C-12; Carbon; Cretaceous; Foraminifera; Hikurangi Trough; IODP Site U1520; International Ocean Discovery Program; Isotope ratios; Isotopes; Marine environment; Mesozoic; Microfossils; Nannofossils; O-18/O-16; Oceanic anoxic events; Organic compounds; Oxygen; Pacific Ocean; Paleo-oceanography; Paleoenvironment; Radiolaria; South Pacific; Southwest Pacific; Stable isotopes; Total organic carbon; Upper Cretaceous; West Pacific
Coordinates: S385810 S385810 E1790756 E1790756
Record ID: 2019023715
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States