Clim. Past Discuss., 9, 2217-2233, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Climate of the Past (CP). Please refer to the corresponding final paper in CP.
Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology
K. T. Lawrence1, I. Bailey2, and M. E. Raymo3
1Lafayette College, Department of Geology and Environmental Geosciences, 102 Van Wickle Hall, Easton, PA 18042, USA
2National Oceanography Centre Southampton, University of Southampton, European Way, Southampton SO14 3ZH, UK
3Lamont-Doherty Earth Observatory, Columbia University, P.O. Box 1000, 61 Route 9W, Palisades, NY 10964, USA

Abstract. Recently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent mis-identification of the depth to the Gauss-Matuyama (G/M) polarity chronozone reversal boundary (2.581 Ma) based on preliminary shipboard paleomagnetic data and offers a new chronology which includes a hiatus between ~ 3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~ 2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology is not valid. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age-model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982.

Citation: Lawrence, K. T., Bailey, I., and Raymo, M. E.: Re-evaluation of the age model for North Atlantic Ocean Site 982 – arguments for a return to the original chronology, Clim. Past Discuss., 9, 2217-2233, doi:10.5194/cpd-9-2217-2013, 2013.
Search CPD
Discussion Paper