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Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 3: Insights from Oligocene–Miocene TEX86-based sea surface temperature reconstructions

التفاصيل البيبلوغرافية
العنوان: Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 3: Insights from Oligocene–Miocene TEX86-based sea surface temperature reconstructions
المؤلفون: J. D. Hartman, F. Sangiorgi, A. Salabarnada, F. Peterse, A. J. P. Houben, S. Schouten, H. Brinkhuis, C. Escutia, P. K. Bijl
المصدر: Climate of the Past, Vol 14, Pp 1275-1297 (2018)
بيانات النشر: Copernicus Publications, 2018.
سنة النشر: 2018
المجموعة: LCC:Environmental pollution
LCC:Environmental protection
LCC:Environmental sciences
مصطلحات موضوعية: Environmental pollution, TD172-193.5, Environmental protection, TD169-171.8, Environmental sciences, GE1-350
الوصف: The volume of the Antarctic continental ice sheet(s) varied substantially during the Oligocene and Miocene ( ∼ 34–5 Ma) from smaller to substantially larger than today, both on million-year and on orbital timescales. However, reproduction through physical modeling of a dynamic response of the ice sheets to climate forcing remains problematic, suggesting the existence of complex feedback mechanisms between the cryosphere, ocean, and atmosphere systems. There is therefore an urgent need to improve the models for better predictions of these systems, including resulting potential future sea level change. To assess the interactions between the cryosphere, ocean, and atmosphere, knowledge of ancient sea surface conditions close to the Antarctic margin is essential. Here, we present a new TEX86-based sea surface water paleotemperature record measured on Oligocene sediments from Integrated Ocean Drilling Program (IODP) Site U1356, offshore Wilkes Land, East Antarctica. The new data are presented along with previously published Miocene temperatures from the same site. Together the data cover the interval between ∼ 34 and ∼ 11 Ma and encompasses two hiatuses. This record allows us to accurately reconstruct the magnitude of sea surface temperature (SST) variability and trends on both million-year and glacial–interglacial timescales. On average, TEX86 values indicate SSTs ranging between 10 and 21 °C during the Oligocene and Miocene, which is on the upper end of the few existing reconstructions from other high-latitude Southern Ocean sites. SST maxima occur around 30.5, 25, and 17 Ma. Our record suggests generally warm to temperate ocean offshore Wilkes Land. Based on lithological alternations detected in the sedimentary record, which are assigned to glacial–interglacial deposits, a SST variability of 1.5–3.1 °C at glacial–interglacial timescales can be established. This variability is slightly larger than that of deep-sea temperatures recorded in Mg ∕ Ca data. Our reconstructed Oligocene temperature variability has implications for Oligocene ice volume estimates based on benthic δ18O records. If the long-term and orbital-scale SST variability at Site U1356 mirrors that of the nearby region of deep-water formation, we argue that a substantial portion of the variability and trends contained in long-term δ18O records can be explained by variability in Southern high-latitude temperature and that the Antarctic ice volume may have been less dynamic than previously thought. Importantly, our temperature record suggests that Oligocene–Miocene Antarctic ice sheets were generally of smaller size compared to today.
نوع الوثيقة: article
وصف الملف: electronic resource
اللغة: English
تدمد: 1814-9324
1814-9332
Relation: https://www.clim-past.net/14/1275/2018/cp-14-1275-2018.pdf; https://doaj.org/toc/1814-9324; https://doaj.org/toc/1814-9332
DOI: 10.5194/cp-14-1275-2018
URL الوصول: https://doaj.org/article/998947f3137a43928d43025931311a3b
رقم الأكسشن: edsdoj.998947f3137a43928d43025931311a3b
قاعدة البيانات: Directory of Open Access Journals
الوصف
تدمد:18149324
18149332
DOI:10.5194/cp-14-1275-2018