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New magnetostratigraphic insights from Iceberg Alley on the rhythms of Antarctic climate during the Plio-Pleistocene

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Reilly, BT, Tauxe, L, Brachfeld, S, Raymo, M, Bailey, I, Hemming, S, Weber, ME, Williams, T, Garcia, M, Guitard, M, Martos, YM, Perez, LF, Zheng, X, Armbrecht, L ORCID: 0000-0002-1213-1257, Cardillo, FG, Du, Z, Fauth, G, Glueder, A, Gutjahr, M, Hernandez-Almeida, I, Hoem, FS, Hwang, J-H, Iizuka, M, Kato, Y, Kenlee, B, O'Connell, S, Peck, V, Ronge, TA, Seki, O, Tripathi, S and Warnock, J 2021 , 'New magnetostratigraphic insights from Iceberg Alley on the rhythms of Antarctic climate during the Plio-Pleistocene' , Paleoceanography and Paleoclimatology, vol. 36, no. 2 , pp. 1-27 , doi: 10.1029/2020PA003994.

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Abstract

International Ocean Discovery Program (IODP) Expedition 382 in the Scotia Sea’s Iceberg Alley recovered among the most continuous and highest resolution stratigraphic records in the Southern Ocean near Antarctica spanning the last 3.3 Myr. Sites drilled in Dove Basin (U1536/U1537) have well-resolved magnetostratigraphy and a strong imprint of orbital forcing in their lithostratigraphy. All magnetic reversals of the last 3.3 Myr are identified, providing a robust age model independent of orbital tuning. During the Pleistocene, alternation of terrigenous versus diatomaceous facies shows power in the eccentricity and obliquity frequencies comparable to the amplitude modulation of benthic δ18O records. This suggests that variations in Dove Basin lithostratigraphy during the Pleistocene reflect a similar history as globally integrated ice volume at these frequencies. However, power in the precession frequencies over the entire ∼3.3 Myr record does not match the amplitude modulation of benthic δ18O records, suggesting Dove Basin contains a unique record at these frequencies. Comparing the position of magnetic reversals relative to local facies changes in Dove Basin and the same magnetic reversals relative to benthic δ18O at North Atlantic IODP Site U1308, we demonstrate Dove Basin facies change at different times than benthic δ18O during intervals between ∼3 and 1 Ma. These differences are consistent with precession phase shifts and suggest climate signals with a Southern Hemisphere summer insolation phase were recorded around Antarctica. If Dove Basin lithology reflects local Antarctic ice volume changes, these signals could represent ice sheet precession-paced variations not captured in benthic δ18O during the 41-kyr world.

Item Type: Article
Authors/Creators:Reilly, BT and Tauxe, L and Brachfeld, S and Raymo, M and Bailey, I and Hemming, S and Weber, ME and Williams, T and Garcia, M and Guitard, M and Martos, YM and Perez, LF and Zheng, X and Armbrecht, L and Cardillo, FG and Du, Z and Fauth, G and Glueder, A and Gutjahr, M and Hernandez-Almeida, I and Hoem, FS and Hwang, J-H and Iizuka, M and Kato, Y and Kenlee, B and O'Connell, S and Peck, V and Ronge, TA and Seki, O and Tripathi, S and Warnock, J
Keywords: magnetostratigraphy, Iceberg Alley, Antarctic climate, Plio-Pleistocene
Journal or Publication Title: Paleoceanography and Paleoclimatology
Publisher: Wiley-Blackwell Publishing Inc.
ISSN: 2572-4517
DOI / ID Number: 10.1029/2020PA003994
Copyright Information:

© 2021. American Geophysical Union.

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