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Oxygen isotopic paleotemperatures across the Runangan—Whaingaroan (Eocene—Oligocene) boundary in a New Zealand shelf sequence

Abstract
Oxygen isotopic compositions of the tests of mainly benthic foraminifera, from sections of conformable Late Eocene (Runangan) to Early Oligocene (Whaingaroan) shelf mudstones, at both Cape Foulwind and Port Elizabeth, western South Island, indicate. that shelf sea paleotemperatures followed the global open-ocean trend towards a Paleogene minimum near the Eocene-Oligocene boundary. Throughout the latest Eocene, temperatures declined steadily by 3°C, showed a temporary minor warming at the Eocene-Oligocene boundary, dropped sharply by 2°C in the Early Oligocene, and ameliorated significantly later in the Early Oligocene. The qualitative temperature trends for New Zealand shelf waters at this time are similar to those inferred from earlier paleontologic syntheses and limited oxygen isotopic work, but involve a range of temperatures within the warm and cool temperate climatic zones and an absolute temperature depression across the Eocene-Oligocene boundary of only 5°C (from about 17 to 12°C). Results are consistent with isotopic paleotemperatures determined from deep-sea sediment cores south of New Zealand where the cooling is inferred to mark the onset of production of Antarctic bottom waters at near-freezing temperatures. © 1981 Taylor & Francis Group, LLC.
Type
Journal Article
Type of thesis
Series
Citation
Burns, D. A., & Nelson, C. S. (1981). Oxygen isotopic paleotemperatures across the Runangan—Whaingaroan (Eocene—Oligocene) boundary in a New Zealand shelf sequence. New Zealand Journal of Geology, and Geophysics, 24(4), 529-538. https://doi.org/10.1080/00288306.1981.10422743
Date
1981-07-01
Publisher
The Royal Society of New Zealand
Degree
Supervisors
Rights
This article has been published in the journal: New Zealand Journal of Geology and Geophysics. © 1981 The Royal Society of New Zealand. Used with permission.