Iron Age (300-1800 AD) Geomagnetic Paleointensity of Southern Africa

铁器时代（公元 300-1800 年）南部非洲的地磁古强度

• 批准号: 0838185
• 负责人: John Tarduno
• 金额: $ 22万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-15 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838185&HistoricalAwards=false
• 关键词: Iron; Age; 300; 1800; AD

The precipitous decay in the intensity of the Earth's dipole magnetic field since 1840 is a robust feature defined by magnetic observatory data. The drop is related to a low magnetic intensity region called the South Atlantic Anomaly, which may be driven by the growth of a prominent reversed magnetic flux core patch off the coast of South Africa. The magnetic dipole history prior to the era of modern observatory measurements is uncertain because of the near lack of archeomagnetic data from the Southern Hemisphere. A paleointensity record of the geomagnetic field for the Southern Hemisphere is potentially held in Iron Age (300 to 1800 AD) ceramics of southern Africa. The Paleomagnetism Research Group at the University of Rochester is analyzing this record. They are combining these paleointensity data with magnetic directions obtained from analyses of oriented archeological materials and other field strength measures using a new technique (the analysis of single grain pottery temper). The ultimate goal of the project is to use the new magnetic records to test geomagnetic field models and contrasting interpretations of the long-term nature of the modern dipole decrease. A Southern Hemisphere archeomagnetic record is of interest to a broad range of scientists, ranging from those studying processes active in the Earth?s core to those interested in the efficiency of magnetic shielding from solar energetic particles. The investigation involves international collaboration with South African archeologists and geologists. The work incorporates graduate and undergraduate student studies and a small number of K-12 activities. The latter integrate the teaching efforts of the University of Rochester Paleomagnetism Research Group with the Rochester community. Outreach activities also include dissemination of the research results in South Africa. This award is co-funded by NSF's Geophysics Program and the Office of International Science and Engineering.

自 1840 年以来，地球偶极子磁场强度的急剧衰减是磁观测数据定义的一个强有力的特征。这种下降与称为南大西洋异常的低磁场强度区域有关，该区域可能是由南非海岸附近一个突出的反向磁通核心斑块的增长驱动的。 由于几乎缺乏来自南半球的古地磁数据，现代天文台测量时代之前的磁偶极子历史是不确定的。 南半球地磁场的古强度记录可能存在于南部非洲铁器时代（公元 300 至 1800 年）的陶瓷中。罗切斯特大学的古地磁研究小组正在分析这一记录。他们使用新技术（单粒陶器回火分析）将这些古强度数据与通过定向考古材料分析和其他场强测量获得的磁方向相结合。 该项目的最终目标是利用新的磁记录来测试地磁场模型以及对现代偶极子减少的长期性质的对比解释。南半球古磁记录引起了广泛科学家的兴趣，从那些研究地核活跃过程的科学家到那些对太阳高能粒子的磁屏蔽效率感兴趣的科学家。该调查涉及与南非考古学家和地质学家的国际合作。这项工作包括研究生和本科生研究以及少量 K-12 活动。后者将罗切斯特大学古地磁研究小组与罗切斯特社区的教学工作结合起来。 外联活动还包括在南非传播研究成果。该奖项由美国国家科学基金会地球物理计划和国际科学与工程办公室共同资助。