权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

In-situ observation of the crystallization kinetics and texture evolution of basalts

玄武岩结晶动力学和结构演化的原位观察

基本信息

批准号：
129863361
负责人：
Professor Dr. Hans Keppler
金额：
--
依托单位：
Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik (BGI)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2009
资助国家：
德国
起止时间：
2008-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/129863361?language=en
关键词：
situ observation crystallization kinetics texture

项目摘要

Crystal size distribution (CSD) theory has been used extensively to interpret the textures of igneous rocks and to extract information on the time scales of crystallization. In a series of experiments using a newly developed high-temperature cell with moissanite (SiC) anvils, it was possible to directly observe the crystallization of magmas under the microscope. The data show that classical CSD theory is fundamentally flawed and does not properly describe the textural evolution of a crystallizing magma. In particular, nucleation of crystals is limited to short events and does not continue once crystals of a phase started to grow. CSD curves are not shifted parallel to themselves with time, but they are rotated due to the effects of proportionate growth, grain coalescence and Ostwald ripening. In the continuation of this project, experiments shall clarify (1) whether crystal nucleation is always limited to short events in the crystallization of a magma, (2) under which conditions proportionate growth occurs (i.e. the growth rate is proportional to the size of a crystal), and (3) whether information on time scales can be reliably extracted from CSD diagrams. To this end, and to provide a quantitative calibration of igneous textures, crystallization experiments with variable cooling rates are planned for basaltic to andesitic melts.

晶体粒度分布（CSD）理论已被广泛用于解释火成岩的结构和提取结晶时间尺度的信息。在一系列实验中，使用新开发的带有碳硅石（SiC）砧的高温池，可以在显微镜下直接观察岩浆的结晶。数据表明，经典的CSD理论是根本性的缺陷，并没有正确地描述结晶岩浆的结构演化。特别地，晶体的成核限于短事件，并且一旦相的晶体开始生长就不继续。CSD曲线不随时间平行移动，但由于成比例生长、晶粒聚结和奥斯特瓦尔德熟化的影响，它们发生旋转。在本项目的后续工作中，将通过实验阐明（1）晶体成核是否总是局限于岩浆结晶过程中的短事件，（2）在何种条件下会发生成比例生长（即生长速率与晶体的大小成比例），以及（3）是否可以从CSD图中可靠地提取时间尺度信息。为此，并提供一个定量校准的火成岩纹理，结晶实验与可变冷却速率计划玄武岩安山质熔体。