SGER: Direct Calibration of the Time Scale of Global Climatic Change

SGER：全球气候变化时间尺度的直接校准

• 批准号: 9204884
• 负责人: Chris Hall
• 金额: $ 1.91万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-15 至 1993-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204884&HistoricalAwards=false
• 关键词: SGER; Direct; Calibration; Time; Scale

This pilot project will attempt obtain precise radiometric ages from critical levels to of an Ocean Drilling Program drill core (site 758). Feldspar mineral grains will be separated from 18 different volcanic tephra layers and then subjected to analysis using the laser 40Ar/39Ar dating technique. This method has unprecedented sensitivity and precision, and if suitable material can be extracted from these volcanic horizons, ages with accuracies to within a few thousand years can be obtained. Since this core been studied using oxygen isotopic and paleomagnetic methods, the time-scale derived could precisely calibrate the entire magnetic and global climate change chronology over the past 5 million years. Divergences between the theoretically expected periodicities of oxygen isotope ratio variations and the standard magnetic reversal time scale have raised serious questions about its accuracy. Laser 40Ar/39Ar dating has probably the greatest potential for resolving these questions. However, the project is 'high-risk' in the sense that is not yet known if sufficient datable material can be obtained from ODP cores. If successful, this project could not only improve the currently accepted time scale of global climatic change, it also has the potential for being able to estimate the response rate of the earth to the now well-established astronomical inputs to the earth's climate system.

该试点项目将尝试获得精确的辐射测量 年龄从临界水平到大洋钻探计划的钻探 核心（地点758）。 长石矿物颗粒将从 18个不同的火山熔岩层，然后进行分析， 采用激光40 Ar/39 Ar定年技术。 该方法具有 前所未有的灵敏度和精度，如果合适的材料， 可以从这些火山层中提取出精确的年龄 在几千年内就可以得到。 由于这个核心 利用氧同位素和古地磁方法进行了研究， 得出的时间尺度可以精确地校准整个磁场 以及过去500万年的全球气候变化年表。 理论上预期的周期之间的分歧 氧同位素比值变化和标准磁反转 时间尺度引起了对其准确性的严重质疑。 激光 40 Ar/39 Ar定年法可能是解决 这些问题。 然而，从某种意义上说，该项目是“高风险”的。 目前还不知道是否有足够可确定日期的材料， 从ODP核心获得。 如果成功，这个项目就不会 只是改进了目前公认的全球气候时间尺度， 变化，它也有潜力能够估计 地球对现在公认的天文学的反应率 对地球气候系统的影响。