Electron Microscopy and Rock Magnetism of Ocean Floor Basalts with Implications for Paleo-Intensity Measurements

洋底玄武岩的电子显微镜和岩石磁性对古强度测量的影响

• 批准号: 9804765
• 负责人: Rob Van der Voo
• 金额: $ 20.8万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804765&HistoricalAwards=false
• 关键词: Electron; Microscopy; Rock; Magnetism; Ocean

9804765 Van der Voo A rock magnetic and electron microscope investigation, using convergent beam electron diffraction, is proposed for iron titanium oxides in ocean-floor basalts that vary between Recent and Jurassic in age, to determine the causes of the observed changes in intensity of marine magnetic anomalies and to examine their implications for paleo-intensity studies. Previously, the reduced magnetic intensity of older ocean-floor basalts was thought to be due to maghemitization, but recent observations have raised questions about this mechanism. If it can be shown that fine-grained titanomagnetite has not always been oxidized in older basalts, then it may well be a source of information about ancient geomagnetic intensities. Because ocean-floor basalts are abundant for times since 150 Ma, unoxidized titanomagnetites could become a promising tool for paleo intensity determinations.=20

9804765货车德沃 岩石磁性和电子显微镜调查，使用会聚束电子衍射，提出了在大洋底玄武岩，不同的最近和侏罗纪的年龄，以确定所观察到的海洋磁异常强度变化的原因，并检查其影响古强度研究。 以前，较老的海底玄武岩的磁场强度降低被认为是由于磁化作用，但最近的观察对这一机制提出了质疑。 如果能够证明细粒钛磁铁矿在更古老的玄武岩中并不总是被氧化的，那么它很可能是关于古代地磁强度的信息来源。 由于海底玄武岩自150 Ma以来一直很丰富，因此未氧化的钛磁铁矿可能成为古强度测定的一种有前途的工具。20