Cyclochronology of the Eocene-Oligocene transition from the Cape Roberts Project-3 core, Victoria Land basin, Antarctica

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• 作者：Simone Galeotti^a ; ^{simone.galeotti@uniurb.it} ; Luca Lanci^a ; Fabio Florindo^b ; Tim R. Naish^c ; ^d ; Leonardo Sagnotti^b ; Sonia Sandroni^e ; Franco M. Talarico^f
• 关键词：Antarctica ; CRP-3 drill hole ; Cyclostratigraphy ; Eocene&ndash ; Oligocene climate transition
• 刊名：Palaeogeography ; Palaeoclimatology ; Palaeoecology
• 出版年：2012
• 期刊代码：68_00310182
• 类别：ear
• 出版时间：1 June, 2012
• 卷：335-336
• 期：Complete
• 页码：84-94
• 文件大小：1927 K

摘要

About 34 million years ago, at the Eocene-Oligocene (E-O) transition, Earth's climate underwent a substantial change from relatively ice-free 鈥済reen house鈥?conditions to a glacial state marked by the establishment of a permanent ice sheet on Antarctica. Our understanding of the Antarctic cryospheric evolution across the E-O climate transition relies on indirect marine geochemical proxies and, hitherto, it has not been possible to reconcile the pattern of inferred ice-sheet growth from these 鈥渇ar-field鈥?proxy records with direct physical evidence of ice sheet behaviour from the proximal Antarctic continental margin. Here we present a correlation of cyclical changes recorded in the CRP-3 drill hole sediment core from the western Ross Sea, that are related to oscillations in the volume of a growing East Antarctic Ice Sheet, with well dated lower latitude records of orbital forcing and climate change across the E-O transition. We evaluate the results in the light of the age model available for the CRP-3A succession. Our cyclostratigraphy developed on the basis of repetitive vertical facies changes and clast peak abundances within sequences matches the floating cyclochronology developed in deep-sea successions for major glacial events. The astrochronological calibration of the CRP-3 succession represents the first high-resolution correlation of direct physical evidence of orbitally controlled glaciation from the Antarctic margin to geochemical records of paleoclimate changes across the E-O climate transition.