A Field-based Test of Remagnetization Hypothesis for the Ecstall Pluton, Coast Mountains Batholith, British Columbia

不列颠哥伦比亚省海岸山脉基岩 Ecstall 冥王星重磁化假说的现场测试

• 批准号: 0440029
• 负责人: Paul Renne
• 金额: $ 26.54万
• 依托单位: Berkeley Geochronology Center
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0440029&HistoricalAwards=false
• 关键词: Field; based; Test; Remagnetization; Hypothesis

This research is focused on clarifying the origin and timing of magnetization recorded in a granitoid body (the Ecstall Pluton) within the Coast Mountains of British Columbia. Research to date has revealed that this pluton was likely magnetized by a process only recently recognized, which arises during unmixing of specific iron-titanium oxides. The unmixing process requires either slow cooling or reheating following the initial intrusion of the magma. The magnetism of the Ecstall pluton varies geographically in such a way that reheating due to a hot shear zone appears likely. The larger importance of this research is that the origin of the variation in magnetism will clarify the outstanding question of whether large portions of the western North American continental crust were accreted to the continent from thousand of kilometers away, as has been inferred from magnetism of this and other rock units in the region. The research entails fieldwork, geochronology, rock magnetism and paleomagnetism, and mineralogical studies including electron microscopy and other materials science techniques.

这项研究的重点是澄清不列颠哥伦比亚省海岸山脉内的花岗岩体（Ecstall Pluton）记录的磁化的起源和时间。迄今为止的研究表明，这种深成体可能是通过最近才认识到的过程被磁化的，该过程是在特定铁钛氧化物的分解过程中产生的。分离过程需要在岩浆最初侵入后缓慢冷却或重新加热。 Ecstall 岩体的磁性因地理位置而异，因此很可能由于热剪切带而重新加热。这项研究更重要的是，磁性变化的起源将澄清一个悬而未决的问题，即北美西部大陆地壳的大部分是否是从数千公里外吸积到大陆上的，正如根据该地区和该地区其他岩石单元的磁性推断的那样。该研究涉及实地考察、地质年代学、岩石磁性和古地磁学以及包括电子显微镜和其他材料科学技术在内的矿物学研究。