A M-sequence geomagnetic polarity time scale that minimizes global spreading rate variations and incorporates cyclostratigraphic information

M 序列地磁极性时间尺度，可最大限度地减少全球扩散率变化并包含旋回地层信息

• 批准号: 0926306
• 负责人: Alberto Malinverno
• 金额: $ 9.81万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926306&HistoricalAwards=false
• 关键词: sequence; geomagnetic; polarity; time; scale

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-2).Current Late Jurassic-Early Cretaceous time scale based on the M-sequence marine magnetic anomalies are not well constrained due to the lack of accurate radiometric ages and due to their reliance on the assumption of constant oceanic spreading rates. While geomagnetic polarity time scales (GPTS) built on the basis of magnetic lineations are gradually being superseded by cyclostratigraphy in the Cenozoic, the marine magnetic anomaly record is still indispensable in the M-sequence GPTS. The PI will endevor to improve the construction of the M-sequence GPTS by: 1) Generating by Monte Carlo sampling a range of GPTSs that result in minimal spreading rate fluctuations in all the magnetic anomaly profiles used, and 2) Using magnetic polarity chron durations estimated from cyclostratigraphic studies to calibrate the GPTS. The key advances of the procedure are the overcoming the constant spreading rate assumption and integration of marine magnetic anomaly data and cyclostratigraphy, which is accomplished by accounting for the respective uncertainties. An important benefit of this quantified uncertainty is that the GPTS can be easily updated with additional data. Broader impacts include student involvement and the usefulness of an accurate time scale for the Late Jurassic and Early Cretaceous Periods for the use of wider community.

该奖项是根据2009年美国复苏和再投资法案（公法111-2）资助的。目前晚侏罗世-早白垩世的时间尺度的基础上的M序列海洋磁异常没有得到很好的限制，由于缺乏准确的放射性年龄，并由于他们的依赖于恒定的海洋扩张速率的假设。虽然建立在磁线理基础上的地磁极性时标在新生代逐渐被旋回地层学所取代，但在M序列地磁极性时标中，海洋磁异常记录仍然是不可缺少的。PI将致力于通过以下方式改进M序列GPTS的构建：1）通过蒙特卡罗采样生成一系列GPTS，这些GPTS导致所有使用的磁异常剖面中的扩展速率波动最小，以及2）使用根据旋回地层学研究估计的磁极性年代持续时间来校准GPTS。该程序的主要进展是克服了恒定扩展率假设，并通过考虑各自的不确定性将海洋磁异常数据和旋回地层学相结合。这种量化的不确定性的一个重要好处是，GPTS可以很容易地更新额外的数据。更广泛的影响包括学生的参与和一个准确的时间尺度为更广泛的社区使用的晚侏罗世和早白垩世时期的有用性。