Processes of Metasomatism in Plutonic Rocks

深成岩的交代作用过程

• 批准号: 8903497
• 负责人: Peter Ortoleva
• 金额: $ 4万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-10-15 至 1991-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8903497&HistoricalAwards=false
• 关键词: Processes; Metasomatism; Plutonic; Rocks

Certain features in large layered intrusions suggest that infiltration-driven metasomatic reactions or other post- solidification processes have played a central role in influencing the final distribution of mineral and chemical components. Features of this kind, recently recognized in the Skaergaard Intrusion, include: a. concretion-like masses of mafic minerals in a felsic matrix; b. irregularly shaped residual islands of earlier rock within a more felsic recrystallized domain; and c. multiply-fingered dendrites of plagioclase-rich rock within a more iron-rich matrix. Phenomena of this kind have also been observed in recent simulations of the reaction/transport equations for water-rock systems. We propose to use modeling to explain the origins of these recrystallization phenomena and to predict other possible post- solidification transformations. Processes to be accounted for in these simulations include grain growth and dissolution, solute diffusion and infiltration transport, fluid flow, and pressure solution. Because our models show that these phenomena occur under well-defined conditions, we shall use the results of the models to interpret commonly observed features in the Skaergaard and other large layered intrusions.

大型分层侵入中的某些特征表明，浸润驱动的分子反应或其他固化过程在影响矿物和化学成分的最终分布方面起着核心作用。 最近在Skaergaard入侵中认可的这种功能包括：a。 长英质基质中的镁铁质矿物质的块状质量； b。 在更长英质重结晶的域内，早期岩石的不规则残留岛；和c。 在更富含铁的基质中，富含斜长石的岩石的树突倍增。 在最近对水岩系统的反应/传输方程的模拟中也观察到了这种现象。 我们建议使用建模来解释这些重结晶现象的起源，并预测其他可能的固化后转换。 这些模拟中要考虑的过程包括晶粒生长和溶解，溶质扩散和浸润运输，流体流量和压力溶液。 由于我们的模型表明这些现象发生在明确的条件下，因此我们将使用模型的结果来解释Skaergaard和其他大分层侵入中常见的特征。