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Eccentricity‐Paced Southern Hemisphere Glacial‐Interglacial Cyclicity Preceding the Middle Miocene Climatic Transition
Author(s) -
Ohneiser C.,
Wilson G. S.
Publication year - 2018
Publication title -
paleoceanography and paleoclimatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.927
H-Index - 127
eISSN - 2572-4525
pISSN - 2572-4517
DOI - 10.1029/2017pa003278
Subject(s) - geology , glacial period , oceanography , paleoclimatology , ice age , interglacial , paleontology , southern hemisphere , climatology , climate change
We present new paleoclimate proxy data from the Southwest Pacific spanning the middle Miocene climatic transition (circa 16.2–13.5 Ma), which indicate a dynamic South Pacific Oceanic system with two periods of increasing and decreasing current strength in response to orbitally paced ice volume variations. A magneto‐biostratigraphic age model provides age control for magnetic susceptibility and Anisotropy of Magnetic Susceptibility data from a mudstone succession in Western Southland, New Zealand. Magnetic susceptibility in this succession reflects changes in carbonate content, which we suggest is proxy for ocean productivity or sea level variations and therefore a proxy for ice volume variations. The Anisotropy of Magnetic Susceptibility data carry a record of deep current strength in response to ice volume changes. Our data show that periods of increased ice volume resulted in the northward migration of erosive currents in this sector of the Pacific and that large, dynamic ice sheets may have persisted in Antarctic during the middle Miocene climatic optimum.