• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Late Cretaceous through Cenozoic climate change on Antarctica: A view from the deep sea.
【24h】

Late Cretaceous through Cenozoic climate change on Antarctica: A view from the deep sea.

机译：通过南极新生代气候变化的白垩纪晚期：深海视野。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The climatic evolution of Antarctica is intimately linked with global climate through the processes of oceanic and atmospheric circulation. Analyses and understanding of different climatic states in the past enable a better understanding of processes that control climate and the likely impact of future climate change.; The climatic evolution of Antarctica and its association with the surrounding oceanic circulation are determined using sediment parameters in cores from around Antarctica. These measures include terrigenous flux rates and grain size analysis, bulk magnetic susceptibility values, and magnetic fabrics, measured in samples obtained from Ocean Drilling Program cores that surround Antarctica. Samples extend through the latest Cretaceous and span the time period from before ice formation occurred on Antarctica in the Cretaceous through the onset of modern conditions. Sites analyzed include the Maud Rise in the southern Atlantic Ocean, Kerguelen Plateau in the southern Indian Ocean, and Rekohu Drift in the southwestern Pacific Ocean.; Results indicate that Antarctic climate between late Cretaceous to middle Eocene oscillated between wet and dry periods (although not desert-like), and paralleled changes in global climate. The middle Eocene to middle Oligocene period encompassed the first episode of major ice growth on Antarctica, beginning at ∼36 Ma, reaching the continental margin ∼34 Ma, and remaining unstable until 30 Ma. This time period is representative of the evolution of the proto-Antarctic Circumpolar Current (ACC), the opening of the Tasman seaway, and subsequent thermal isolation of Antarctica; the Drake Passage opened to allow at least surface circulation by ∼32 Ma. The ACC and thermohaline circulation established their present configuration by approximately 23 Ma, resulting in scouring and/or large sediment accumulations by the Pacific Deep Western Boundary Current. Fluctuations related to the intensity of bottom water formation, reflecting Antarctic climate, are recorded during this time, including major growth of the East Antarctic Ice Sheet between 14-11 Ma and the initial formation of the West Antarctic Ice Sheet at ∼10 Ma. The East Antarctic Ice Sheet exhibited fluctuations from at least 6.4 Ma until ∼4 Ma. Significantly, the stable cold-based ice sheet becomes established after 4 Ma, during a period of global warmth.
机译：南极洲的气候演变通过海洋和大气环流的过程与全球气候密切相关。过去对不同气候状态的分析和理解使人们能够更好地了解控制气候的过程以及未来气候变化的可能影响。南极洲的气候演变及其与周围海洋环流的联系是利用南极洲周围岩心中的沉积物参数确定的。这些措施包括从南极洲周围的海洋钻探计划岩心获得的样品中测量的陆源通量率和粒度分析，体积磁化率值和磁性织物。样品一直延伸到最新的白垩纪，并跨越了从现代条件到白垩纪南极洲冰层形成之前的时间段。分析的地点包括南大西洋的莫德河上升，南印度洋的克格伦高原和西南太平洋的雷科胡河漂流。结果表明，白垩纪晚期至中始新世之间的南极气候在干湿期之间波动（尽管不是像沙漠一样），并且与全球气候变化平行。中始新世至渐新世中期包括南极洲主要的冰生长的第一阶段，始于〜36 Ma，到达大陆边缘〜34 Ma，并保持不稳定直至30 Ma。这个时间段代表了原南极洲极地电流（ACC）的演化，塔斯曼海道的开放以及南极洲随后的热隔离；德雷克海峡开放，至少允许地面环流〜32 Ma。 ACC和热盐环流在大约23 Ma时建立了它们当前的构造，导致太平洋深西部边界流冲刷和/或大量沉积物堆积。在这段时间内记录了与反映南极气候的底水形成强度有关的波动，包括​​东南冰盖在14-11 Ma之间的主要增长和西南冰盖在10 Ma左右的初始形成。南极东部冰盖的波动范围从至少6.4 Ma到〜4 Ma。值得注意的是，在全球变暖期间，稳定的冷基冰盖在4 Ma之后就建立了。

著录项

  • 作者

    Joseph, Leah Helen.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 205 p.
  • 总页数 205
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号