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Characterizing the Plio-Pleistocene evolution of sea surface conditions using the alkenone organic proxy.

機譯：使用烯酮有機替代物表征海表條件的上新世更新世演化。

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摘要

Concern about future changes in Earth's climate has generated intense interest in the past behavior of the climate system. Over the past 5 million years the Earth's climate has transitioned from the warm early Pliocene interval, to the colder, more variable late Pliocene and Pleistocene periods, which were marked by the growth of large ice-sheets in the Northern Hemisphere. This dissertation applies a novel approach to understanding this important climatic transition by using the alkenone organic proxy to characterize past climatic variations in sea surface temperature and productivity. This work reviews the discovery, development, calibration, and potential caveats to the application of the alkenone organic proxy, explicitly examining the use of this method to study climatological problems over long (>1 Myr) timescales and concluding that there is enormous potential to apply this valuable tool to the study of long-term paleoclimate. Additionally, this dissertation documents the application of the alkenone organic proxy to the characterization of long-term climatic change at sites in the Coral Sea, eastern equatorial Pacific (EEP) and North Atlantic. Results from the western Coral Sea indicate that the late Quaternary rise of the Australian Great Barrier Reef was not caused by a warming of regional sea surface temperatures as previously proposed and highlights the ability of the alkenone organic proxy to provide valuable climate information in regions where carbonate diagenesis has rendered other commonly used carbonate-based techniques unreliable. Work from the EEP and North Atlantic provide the first continuous, high-resolution records of variations in sea surface conditions through the Plio-Pleistocene climatic transition. These records indicate marked spatial heterogeneity in the evolution of sea surface temperature and productivity during this time interval. These datasets probe the validity of several existing theories for the Plio-Pleistocene transition and lay the foundation for an array of sites that will provide a spatial fingerprint of Pliocene to modern sea surface conditions.
機譯：對地球氣候未來變化的擔憂引起了人們對氣候系統(tǒng)過去行為的濃厚興趣。在過去的五百萬年中，地球的氣候已經從上新世早期的溫暖期過渡到了上新世和更新世晚期的冷，多變時期，其特征是北半球大冰蓋的生長。本文通過使用烯酮有機替代物表征過去的海面溫度和生產力的氣候變化，運用一種新穎的方法來理解這一重要的氣候變化。這項工作回顧了烯酮有機替代物的應用的發(fā)現(xiàn)，開發(fā)，校準和潛在的警告，明確檢查了該方法在長期（> 1 Myr）范圍內研究氣候問題的使用，并得出了應用的巨大潛力這個長期研究古氣候的有價值的工具。此外，本論文還證明了烯酮有機替代物在表征珊瑚海，赤道東太平洋和北大西洋的長期氣候變化中的應用。西部珊瑚海的結果表明，澳大利亞大堡礁第四紀晚期的上升不是由先前提議的區(qū)域海表溫度升高引起的，并且突顯了烯酮有機替代物在碳酸鹽含量較高的地區(qū)提供有價值的氣候信息的能力。成巖作用使其他常用的基于碳酸鹽的技術不可靠。 EEP和北大西洋的工作通過上新世-上新世氣候過渡，提供了第一批連續(xù)的高分辨率海面條件變化記錄。這些記錄表明，在此時間間隔內，海表溫度和生產力的演變具有明顯的空間異質性。這些數(shù)據(jù)集探究了上新世至上新世過渡的幾種現(xiàn)有理論的有效性，并為一系列站點提供了基礎，這些站點將為現(xiàn)代海面條件提供上新世的空間指紋。

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  • 作者

    Lawrence, Kira Trillium.;

  • 作者單位

    Brown University.;

  • 授予單位 Brown University.;
  • 學科 Geology.; Geochemistry.
  • 學位 Ph.D.
  • 年度 2006
  • 頁碼 268 p.
  • 總頁數(shù) 268
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 地質學;地質學;
  • 關鍵詞

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