Timing and extent of late neogene glacials/interglacials using magnetostratigraphy

利用磁地层学研究新近纪晚期冰川/间冰期的时间和范围

• 批准号: 581-2006
• 负责人: Barendregt, René
• 金额: $ 1.43万
• 依托单位: University of Lethbridge
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=388301
• 关键词: Timing; extent; late; neogene; glacials

Ongoing studies reveal complexities of Earth's climate system.  Realities of global warming (and cooling) affect all people.  Quality of life is strongly allied to economic productivity, environmental health, and population dynamics, and each are affected by or adapt to climate changes. Glaciation and deglaciation of Canada rank amongst the most extreme and fundamental climatic events. Investigations of northern and western regions of Canada reveal extensive suites of sediments containing paleoclimatic proxies extending back 3.0 million years.  Sediments from these regions occur in climate zones that are particularly sensitive to global warming and cooling.   Sedimentary records span a wide spectrum of time scales, ranging from decades to millions of years and are expressed with varying powers of resolution.  A longstanding issue in use of proxy data is correlation of terrestrial and marine records.  Each contains valuable information that can assist in the interpretation of the other.  Magnetostratigraphy affords the best opportunity to correlate sedimentary and fossil records from these two environments, largely because reversals of the Earth's magnetic field are essentially synchronous over the surface of the earth and are independent of the type of sedimentary facies in which the record is held. Ongoing research will focus on: (1) new magnetostratigraphies that will better constrain timing and extent of ice sheets.  Particularly important are paleomagnetic measurements of glacial tills and outwash (direct evidence of glaciation), and paleosols which develop during ice-free periods.  (2)  The magnetic "finger-printing" of preglacial, glacial, and non-glacial sediments in gold and diamond producing areas can  provide valuable information about provenance, age, mode of deposition, and relationship to ice margins, explaining why only some deposits contain placers. (3) In the past 4 years paleosecular records have been developed from rythmites deposited by glacial outburst floods.  Here magnetostratigraphy provides a means to assess length of time over which deposits were laid down, and a better understanding of dynamics of deglaciation.

正在进行的研究揭示了地球气候系统的复杂性，全球变暖（和变冷）严重影响所有人的生活质量，这与经济生产力、环境健康和人口动态密切相关，并且每个人都受到气候变化的影响或适应气候变化。加拿大的冰消期是最极端和最根本的气候事件之一。对加拿大北部和西部地区的调查显示，大量沉积物含有可追溯到 300 万年前的古气候指标。这些沉积物发生在对全球变暖和变冷特别敏感的气候带中。沉积记录的时间尺度很广，从几十年到几百万年不等，并且以不同的分辨率来表达，这是一个长期存在的问题。代理数据的核心是陆地和海洋记录的关联。每个记录都包含有助于解释另一个的有价值的信息，磁地层学为关联这些记录和化石记录提供了最佳机会。两种环境，主要是因为地球磁场的反转在地球表面基本上是同步的，并且与记录所在的沉积相类型无关，正在进行的研究将集中在：（1）更好的新磁地层学。限制冰盖的时间和范围特别重要的是冰碛物和冲刷（冰川作用的直接证据）以及无冰期间形成的古土壤的古地磁测量。 (2) 黄金和钻石产区的冰期前、冰期和非冰期沉积物的磁性“指纹”可以提供有关来源、年龄、沉积模式以及与冰缘关系的宝贵信息，并解释为什么(3) 在过去的 4 年中，古地质记录是根据冰川爆发洪水沉积的节律岩形成的。意味着评估沉积物沉积的时间长度，并更好地了解冰川消融的动态。