10Be in Ocean Sediments as an Indicator of past Changes in Cosmic ray Flux Produced by Terrestrial and ExtraterrestrialProcesses

10 海洋沉积物中的 Be 作为陆地和地外过程产生的宇宙射线通量过去变化的指标

• 批准号: 9017728
• 负责人: Paul Damon
• 金额: $ 5.36万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-03-15 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9017728&HistoricalAwards=false
• 关键词: 10Be; Ocean; Sediments; Indicator; past

There is increasing evidence that the geomagnetic dipole moment was less than one half of its present value prior to 15,000 B.P. This would lead to an increase in 10Be and 14C production by 40%. Short term variations in the cosmic ray flux are also thought to have occurred. For example, two spikes in 10Be concentrations in the Vostok ice core from Antarctica have been found. It seems unlikely that they were formed due to a change in climatic conditions. The increase of 10Be is probably due to an increase in production of 10Be due to increased cosmic ray activity in the atmosphere induced by supernovae or geomagnetic excursions. A hemipelagic sediment core from the Blake Outer Ridge and a varved sediment core from the Gulf of California offer a good opportunity to observe variations in 10Be and 14C production during the last 100,000 years because of continuous, constant, and high rate of sedimentation on the cores. Ocean sediments should provide an important archive of data concerning changes in 10Be production. Unlike the ice cores, the ca. 300-year residence time of 10Be in the sea minimizes local variations due to climate. Correlation of 10Be "events" between both cores should establish whether the events are of worldwide or local origin. In addition, paleomagnetic data have already been measured in the cores making correlation possible with the 10Be production curve. Sedimant samples are to be analyzed for 10Be and 14C at the TAMS facility at the University of Arizona. 9Be will be measured by atomic absorption spectrophotometry. Reservoir models will be evaluated to define the nature of the event.

越来越多的证据表明地磁偶极子 当时的价值还不到现在的一半。 15，000 B.P.这将导致10Be和14C的增加 产量40%。 宇宙线通量的短期变化 也被认为发生过。 例如，两个峰值 南极洲东方冰芯中的10Be浓度 它们似乎不太可能是由于 气候条件的变化。 10Be的增加可能是 由于10Be的产量增加，由于宇宙能量的增加， 由超新星引起的大气中的射线活动， 地磁漂移 一个半远洋沉积物岩心， 布莱克外脊和一个来自墨西哥湾的纹状沉积物岩心 加州提供了一个很好的机会来观察10 Be的变化 在过去的10万年里， 连续、恒定和高速率的沉积， 丹 海洋沉积物应该提供一个重要的档案， 关于10Be生产变化的数据。 不像冰 核心，CA。300-10Be在海水中的停留时间 最大限度地减少因气候而产生的局部变化。 10Be的相关性 两个核心之间的“事件”应该确定事件是否 是世界性的还是地方性的。 此外，古地磁 已在岩心中测得数据， 10Be生产曲线。 沉积物样品应 在美国国家航空航天局的TAMS设施进行10Be和14C分析。 亚利桑那大学。 9 Be将通过原子吸收测量 分光光度法 将对储层模型进行评价， 事件的性质。