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An assessment of Antarctic ice sheet dynamics from a Pliocene polar paleoclimate archive.

机译：来自上新世极古气候记录的南极冰盖动力学评估。

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摘要

The potential impact of East Antarctic Ice Sheet (EAIS) response to warming over the next century is of major concern, particularly due to its influence on sea level rise. Efforts to understand its impact are limited due to the restrictions of short-term modeling, as well as the assumption that all ice behaves similarly across the EAIS, meriting the need for further study over longer time periods. The early Pliocene (5.33-2.58 Ma) is the most suitable period of time in which to assess EAIS dynamics because of its similarity to modern tectonic configuration and similar CO2 estimates (~400 ppm). Due to a paucity of records, the present study expands on the existing knowledge of ice sheet dynamics by providing a reconstruction of ice-rafting history in a previously unstudied sector of the EAIS. The aim of this study is to evaluate the behavior of the Wilkes Land ice sheet and whether its response is part of a continental response or on a smaller, local scale. A high-resolution record of ice-rafting history in the Wilkes Land region from IODP Site U1359 was used to (1) identify periods of advance and retreat during the early Pliocene, (2) determine the orbital variations within the ice-rafting record, (3) assess the effects of warming on the interaction between the ice sheet and Southern Ocean during the Pliocene Climatic Optimum and (4) evaluate the behavior of the EAIS during early Pliocene warmth through regional correlation. A time series analysis to assess the orbital variations of the ice sheet determined a transition from obliquity forced to precession forced variability of ice-rafting ~4.6 Ma. Concurrently, geochemical analysis revealed enhanced downwelling may have lead to greater venting of CO2 during deglaciation, accompanied by higher productivity in response to increased iron-bearing dust fertilization. A regional correlation shows that the ice sheet was susceptible to warming during the Pliocene Climatic Optimum, as opposed to the later mid-Pliocene Warm Period, where the ice sheet remained in a retreated position.
机译：南极东部冰盖（EAIS）对下一世纪变暖的潜在影响引起了人们的极大关注，特别是由于其对海平面上升的影响。由于短期建模的限制以及假设所有冰在整个EAIS中的行为类似，因此了解其影响的努力受到限制，因此有必要在更长的时间内进行进一步研究。上新世早期（5.33-2.58 Ma）是评估EAIS动态的最合适的时间段，因为它与现代构造构造相似且对CO2的估算也相似（约400 ppm）。由于缺乏记录，本研究通过重建EAIS以前未被研究的部门中的浮冰历史，从而扩展了冰原动力学的现有知识。这项研究的目的是评估威尔克斯陆地冰原的行为，以及其响应是大陆响应的一部分还是局部规模较小的响应。来自IODP网站U1359的威尔克斯陆地地区滑冰历史的高分辨率记录用于（1）确定上新世早期的进退时期，（2）确定滑冰记录内的轨道变化， （3）在上新世气候最佳时期评估变暖对冰盖与南大洋相互作用的影响，（4）通过区域相关性评估在上新世早期温暖时期EAIS的行为。评估冰盖轨道变化的时间序列分析确定了从倾角强迫向旋进〜4.6 Ma的进动强迫变化的过渡。同时，地球化学分析表明，下沉深度的增加可能会导致在冰消融过程中释放出更多的二氧化碳，并伴随着含铁粉尘施肥的增加而提高了生产率。区域相关性表明，在上新世气候最佳时期，冰盖容易变暖，而在上新世中期后期，冰盖仍处于后退位置。

著录项

  • 作者

    Hansen, Melissa A.;

  • 作者单位

    Montclair State University.;

  • 授予单位 Montclair State University.;
  • 学科 Paleoclimate science.;Climate change.;Marine geology.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 239 p.
  • 总页数 239
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 等离子体物理学;
  • 关键词

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