| 项目编号: | 1632754
|
| 项目名称: | Collaborative Research: Resolving the Controversy of REE Diffusion in Olivine |
| 作者: | Daniele Cherniak
|
| 承担单位: | Rensselaer Polytechnic Institute
|
| 批准年: | 2016
|
| 开始日期: | 2016-04-01
|
| 结束日期: | 2018-03-31
|
| 资助金额: | 16200
|
| 资助来源: | US-NSF
|
| 项目类别: | Standard Grant
|
| 国家: | US
|
| 语种: | 英语
|
| 特色学科分类: | Geosciences - Earth Sciences
|
| 英文关键词: | olivine
; ree diffusion
; ree
; diffusion
; laboratory diffusion experiment
; current controversy
; exploratory research
; team
; diffusion measurement
; multicomponent diffusion
; mineral olivine
; relative diffusion rate
; ree concentration
; new ree-in-olivine-clinopyroxene thermometer
|
| 英文摘要: | This Early Grant for Exploratory Research (EaGER) award is designed to resolve a current controversy regarding the rate of diffusion of rare earth element (REE) in the mineral olivine that is the most common phase in the Earth's upper mantle. Diffusivities of REE derived from two past studies differ by 3~4 orders of magnitude, which has profound implications for the interpretation of questions such as how fast basaltic magmas ascend from depths in the Earth and planetary interiors and if chemical variations observed in olivine-hosted melt inclusions are reliable records of mantle source heterogeneity. If REE diffusion in olivine is indeed very fast, conclusions derived from recent studies must be re-evaluated. For that reason, the petrology and geochemistry community is interested in clarifying the issue quickly. This EaGER will provide support for the training of a post-doctoral fellow.
The project will integrate theoretical, analytical and experimental approaches to evaluate and determine the source of discrepancy in the two data sets. The team hypothesizes that there is a possibility that two time scales for REE diffusion in olivine may operate under specific conditions. In order to test this hypothesis, the team will conduct a series of laboratory diffusion experiments to evaluate if the presence of major element concentration gradients, differing REE concentrations, and substitutional mechanisms are at the source of the discrepant results from different studies. The experiments will be accompanied by closure temperatures determinations of REE and Ca-Fe-Mg in olivine from natural samples using a new REE-in-olivine-clinopyroxene thermometer, enabling a better comparison of relative diffusion rates between the trivalent and divalent cations in olivine from mafic and ultramafic rocks that experienced different cooling rates. To better understand diffusion measurements from the two laboratories and their connection to observations in natural samples, the team also plans to undertake a theoretical study examining the effects of major element concentration gradient and chemical strain energy on REE diffusion in olivine. The ultimate goal of this EaGER study is not only to resolve the controversy surrounding REE diffusion in olivine, but also to develop a framework for understanding the time scales of diffusion for the trace elements and major elements during multicomponent diffusion in other rock-forming minerals. |
| 资源类型: | 项目
|
| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92599
|
| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
|
|
There are no files associated with this item.
|
| Recommended Citation: | |
Daniele Cherniak. Collaborative Research: Resolving the Controversy of REE Diffusion in Olivine. 2016-01-01.
|
|
|