Experimental calibration of garnet- and pyroxene-diffusion-chronometry and -thermometry for applications to terrestrial and planetary samples

适用于陆地和行星样品的石榴石和辉石扩散计时和测温的实验校准

• 批准号: 321555708
• 负责人: Professor Dr. Sumit Chakraborty, Ph.D.
• 金额: --
• 依托单位: Department of Materials
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321555708?language=en
• 关键词: Experimental; calibration; garnet; pyroxene; diffusion

There is an increasing recognition that many geological processes occur in pulses, or are too short to be captured by long-lived radiogenic isotopes. Moreover, thermal histories in many high temperature settings in the Earth (e.g. metamorphic, plutonic and volcanic systems) as well as in planetary systems such as asteroid parent bodies or the lunar or Martian interior often follow non-linear paths. These require tools that can monitor processes continuously and over a range of different timescales. Diffusion chronometry is one such tool that is being increasingly used to address these issues. In spite of the rapid developments, there remain critical experimental parameters that are needed for the determination of timescales in all of the above settings that could not be collected so far because of experimental limitations. New experimental developments now make it possible to determine these critical parameters. In this project we wish to use these novel experimental advances to determine diffusion coefficients and partition coefficients (required as geothermometers for use as boundary conditions in diffusion models) in the garnet- orthopyroxene-clinopyroxene system, which can be widely used in all of the above settings. Therefore, results from this study would considerably expand the scope of diffusion chronometry. An added advantage of studying this system is that compositions of these phases are used to determine pressures, temperatures and fluid activities. Thus, timescales obtained from diffusion chronometry with these minerals can be directly related to specific processes and conditions that a rock experienced during its evolution.

人们越来越认识到许多地质过程发生在脉冲中，或者太短，无法被长寿命的放射原同位素捕获。此外，地球许多高温设置（例如变质，岩石和火山系统）以及行星系统（例如小行星母体或月球或火星内部）通常遵循非线性路径的热量历史。这些需要工具，可以连续监视过程，并在不同的时间范围内监视过程。扩散时间表是一种越来越多地用于解决这些问题的工具。尽管有快速的发展，但仍需要关键的实验参数来确定上述所有设置，这些时间尺度由于实验局限性而无法收集。现在，新的实验发展使确定这些关键参数成为可能。在该项目中，我们希望使用这些新颖的实验进步来确定石榴石 - 邻苯二甲烯 - 纤维素二磷酸系统中的扩散系数和分区系数（作为扩散模型中的边界条件的地热测定器所需的扩散系数（需要用作边界条件），这可以在上述所有设置中广泛使用。因此，这项研究的结果将大大扩大扩散时间表的范围。研究该系统的另一个优点是，这些阶段的组成用于确定压力，温度和流体活动。因此，通过这些矿物质从扩散时间表获得的时间尺度可以直接与岩石在其演化过程中经历的特定过程和条件有关。