Pleistocene seismic sequences may result from eustatic change but can they be used for global correlations? New insights from the Canterbury Basin, New Zealand

Author(s): McHugh, C. M.; Fulthorpe, C.; Hoyanagi, K.; Blum, P.
Author Affiliation(s): Primary:
CUNY, Queens College, Department of Earth & Environmental Sciences, Flushing, NY, United States
University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
Shinshu University, Department of Geology, Matsumoto, Japan
Texas A&M University, USIO Integrated Ocean Drilling Program, College Station, TX, United States
Volume Title: AGU 2013 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2013; American Geophysical Union 2013 fall meeting, San Francisco, CA, Dec. 9-13, 2013. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: To understand the influence of eustasy on continental margin sedimentation and test the concepts of sequence stratigraphy, Integrated Ocean Drilling Program Expedition 317 drilled four sites on the continental shelf and upper slope of the Canterbury Basin, eastern South Island, New Zealand. We present results from upper slope Site U1352 (320 m water depth). A high-resolution multiproxy approach involving geochemical elemental analyses, lithostratigraphy and biostratigraphy, calibrated to an oxygen isotope scale, was applied to understand sedimentation over the past ≈1.8 million years. Multichannel seismic data (EW00-01 survey) provided a seismic sequence stratigraphic framework against which to interpret the data. Seismic sequence boundaries are represented by a unique geochemical signature and arrangement of overlying sedimentary facies. However, several such geochemical-lithologic units are commonly contained within each seismic sequence. These higher frequency, intrasequence geochemical units generally correlate with 100 ky glacial-interglacial Milankovic variability in the late Pleistocene, revealing that it took several glacio-eustatic cycles to build each seismic sequence. These findings support prior results obtained from Pleistocene sediments recovered by Ocean Drilling Program Leg 174A that drilled on the New Jersey margin with similar objectives to those of Expedition 317. In both northern and southern hemisphere siliciclastic settings there is a strong correlation between seismic sequences and glacio-eustasy, but the correlation between isotopic cycles and sequence boundaries is not one-to-one: only a subset of the glacioeustatic cycles result in a preserved seismic sequence boundary. Furthermore, late Pleistocene sequence boundaries on the two margins are not synchronous. Local conditions cause different isotopic peaks to be preferentially preserved as sequence boundaries in each location and preserved seismic sequences contain different groupings of marine isotope stages. Therefore, high-frequency Pleistocene seismic sequences may not correlate globally even though they are driven by glacio-eustasy.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Canterbury Basin; Cenozoic; Cores; Expedition 317; Integrated Ocean Drilling Program; Marine sediments; Pacific Ocean; Pleistocene; Quaternary; Sediments; South Pacific; Southwest Pacific; West Pacific
Coordinates: S445700 S444600 E1720200 E1714000
Record ID: 2015085861
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