25 Million Years of Mantle Upwelling below the Mid Atlantic Ridge: The Vema Lithopsheric Section Revisited

大西洋中脊以下地幔上涌 2500 万年：重温维玛岩石层剖面

• 批准号: 0551288
• 负责人: Enrico Bonatti
• 金额: $ 34.13万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0551288&HistoricalAwards=false
• 关键词: 25; Million; Years; Mantle; Upwelling

ABSTRACT Bonatti (0551288)Intellectual Merit: This research is the continuation of a project that studies an uplifted sliver of oceanic lithosphere that exposes upper mantle and seafloor crustal units along the Vema Lithospheric Section. This field area provides an opportunity to monitor how processes of seafloor lithospheric generation have changed over the last 25 million years. The project combines multibeam, gravity, magnetics and seismic reflection geophysical data with geochemical and isotopic analyses of closely spaced geochemical samples of the exposed mantle ultramafic basal units and the crustal basaltic units. Samples of peridotites, gabbros, and basalts (including fresh glass) were collected during the April-May 2005 field season augmenting the original study by 32 additional sites and extending the time coverage of the sample suite by 10 million years. Geochemical work includes major and trace element analyses of mantle equilibrated pyroxenes and spinels. These data will be used to refine patterns of mantle thermal properties, composition, and melting processes. Major and trace element analyses of basaltic glasses will be used to obtain independent estimates of the extent of mantle melting. Sr-Nd-Pb isotope compositions of pyroxenes from peridotites and basaltic glasses will be used to determine genetic links between the mantle and crustal basalts. Results will test the idea that short-scale isotopic heterogeneities of upper mantle peridotites are homogenized in the melt that derives from a broad region of the upper mantle. Combined geochemical and geophysical data from the study will permit 3D modeling of lithosphere formation. Broader impacts: This project will fund researchers from New York State, one of whom is a female, early career scientist. Undergraduates will be involved in the research as will faculty and students at the urban Queens College campus of the City University of New York which has a high enrollment of minorities under-represented in the sciences. Analytical data will be archived and made available to the public through the PetDb petrologic database at Lamont-Doherty Earth Observatory.

摘要Bonatti（0551288）智力优点：这项研究是研究一个研究的项目，该项目研究了沿Vema岩石圈部分沿着海底地幔和海底地壳单元暴露的海洋岩石圈的升高。 该野外区域提供了一个机会，可以监视过去2500万年中海底岩石层产生的变化。 该项目结合了多束，重力，磁性和地震反射地球物理数据与地球化学和同位素分析的裸露地幔超镁质基底单位和地壳底层单位的地球化学样品的地球化学和同位素分析。 在2005年4月 - 5月的田间季节中收集了橄榄岩，gabbros和玄武岩的样品（包括新鲜玻璃），从而增加了32个地点的原始研究，并将样本套件的时间覆盖范围延长了1000万年。 地球化学工作包括地幔平衡的辉石和尖晶石的主要和痕量元素分析。 这些数据将用于完善地幔热性能，组成和熔化过程的模式。 玄武岩玻璃的主要和痕量元素分析将用于获得地幔熔化程度的独立估计。 来自橄榄岩和玄武岩玻璃的辉石的SR-ND-PB同位素组成将用于确定地幔和地壳玄武岩之间的遗传联系。 结果将测试以下观点：上地幔橄榄岩的短尺度同位素异质性是在熔化的熔体中匀浆的，该熔体来自上地幔的宽区域。研究的地球化学和地球物理数据将允许岩石圈形成的3D建模。更广泛的影响：该项目将为纽约州的研究人员提供资金，其中一位是女性的早期职业科学家。本科生将参与这项研究，纽约市皇后大学校园的教职员工和学生将参与研究，纽约市皇后学院校园的少数民族少数人数不足。 分析数据将通过Lamont-Doherty Earth天文台的PETDB Petrologic数据库进行存档并提供给公众。