Quantitative Modeling of Infiltration in Layered Intrusions

层状侵入体渗透的定量建模

• 批准号: 0206905
• 负责人: A. Boudreau
• 金额: $ 15.81万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0206905&HistoricalAwards=false
• 关键词: Quantitative; Modeling; Infiltration; Layered; Intrusions

BoudreauEAR-0206905Igneous intrusions such as the Bushveld Complex of South Africa and the Stillwater Complex of Montana host much of the world's reserves of economically valuable elements such as chromium and the platinum-group elements. Although subject to numerous studies, there is still surprisingly little agreement on how they crystallized and differentiated. A significant part of the proposed study involves extending a numerical model that links an equilibrium crystallization routine (based on the MELTS algorithm of Ghiorso and coworkers) with one-dimensional heat and mass transport equations that include compaction equations of McKenzie. Examples of areas the work would be extended include the addition of spinels to the program and investigation of the formation of economically important chromite-rich layers that occur in layered intrusions. On a parallel track, we will look at details of mineral-mineral trace element partitioning to test if concentrations of temperature-dependent trace elements are affected by compaction-driven recrystallization. Specifically, laser ablation-ICP-MS and electron microprobe mineral mapping and bulk mineral analysis will test if mineral-mineral partitioning is correlated textural and/or modal variations.Finally, we wish to test if one can infer concealed intrusion geometry from crystal size distribution (CSD) data. This will be tested by comparing existing data with new Lower and Critical zone samples to be collected where the Lower is both unusually thick over footwall embayments (i.e., the "Burgersfort Bugle") and where the Lower and Critical zone onlap the floor rocks in the eastern Bushveld. If successful, this will further demonstrate that texture is locally evolved and not necessarily a function of minerals transported from elsewhere.

BoudreauEAR-0206905南非的布什维尔德杂岩体和蒙大拿州的斯蒂尔沃特杂岩体等火成岩侵入体蕴藏着世界上大部分具有经济价值的元素储量，例如铬和铂族元素。 尽管进行了大量的研究，但令人惊讶的是，对于它们如何结晶和分化仍然没有达成一致。拟议研究的一个重要部分涉及扩展一个数值模型，该模型将平衡结晶例程（基于 Ghiorso 及其同事的 MELTS 算法）与一维热和质量传输方程（包括 McKenzie 的压实方程）联系起来。该工作将扩展的领域的例子包括在计划中添加尖晶石以及调查层状侵入体中出现的具有经济意义的富铬铁矿层的形成。 在并行轨道上，我们将研究矿物-矿物微量元素分配的细节，以测试与温度相关的微量元素的浓度是否受到压实驱动的重结晶的影响。 具体来说，激光烧蚀-ICP-MS 和电子探针矿物测绘和块状矿物分析将测试矿物-矿物分配是否与结构和/或模式变化相关。最后，我们希望测试是否可以从晶体尺寸分布推断隐藏的侵入几何形状(CSD) 数据。 这将通过将现有数据与要收集的新下层和临界区样本进行比较来测试，其中下层在下盘海湾（即“伯格斯堡号”）上异常厚，并且下层和临界区重叠在底部岩石上布什维尔德东部。 如果成功，这将进一步证明质地是局部进化的，并不一定是从其他地方运输的矿物质的作用。