Collaborative Research: Incorporating Temperature-dependent Physical Properties into Numerical Models of Magmatic and Related Hydrothermal Systems

该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。地球内部的大多数地质过程都是由热量传递驱动的。这些过程包括岩浆生成、火山作用、地热系统和几种类型矿床的生成。目前用于研究这些过程的数学和计算机模型通常假定岩石的几个基本属性为固定值，例如热容量，即岩石的保热能力，热扩散率，即岩石传递热量的能力，以及熔化岩石所需的热量。许多类型岩石的这些性质的值，特别是它们如何随温度变化，仍然鲜为人知，研究的一个方面集中在实验室的实验测量上。然后，这些新值将被用于模拟地壳内通过持续或断续的岩浆注入而具有良好特征的岩浆体的生长，以及这些深成岩的生长和结晶如何驱动周围岩石和地热系统的变质作用。该项目将提供一个机会，培训学生和年轻科学家进行研究，这些研究将包括实验室、计算和现场组成部分。从多个角度观察复杂自然过程的能力是培养成功的地学家的关键。由于对花岗岩岩体如何构成的理解最近取得了进展，而且侵入引起的变质和地热系统通常比简单的传导和对流热模型预测的持续时间更长，因此需要改进岩石随温度变化的属性数据，并将其纳入综合热模型中。从将深成岩浆视为以底辟形式存在于单个脉冲中的大量岩浆，转变为将深成岩浆视为在较长时期内生长的物体，从数万年到数百万年不等。岩浆的长期注入会影响深成岩浆的结晶历史和变质-地热系统的持续时间，所有这些都受热传递的控制。该项目的目的是确定矿物和岩石随温度变化的性质，并开发岩浆-变质-地热系统的综合数值模型。该模型将通过检查黑山Harney Peak花岗岩岩体的生长及其对热晕的影响来进行现场测试。这些实验室数据将对研究许多其他地质环境中的过程的工作人员有用。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Most geologic processes within the interior of the Earth are driven by heat transfer. These processes include magma generation, volcanism, geothermal systems, and generation of several types of ore deposits. Current mathematical and computer models used to study these processes generally assume fixed values for several fundamental properties of rocks such as heat capacity, that is the ability of rocks to hold heat, thermal diffusivity, that is the ability of rocks to transfer heat, and the amount of heat that is necessary to melt rocks. The values of these properties for many types of rocks, in particular how they vary with temperature, are still poorly known, and one aspect of the research focuses on experimental measurements in the laboratory. The new values will then be applied to modeling the growth of well-characterized magma bodies within the Earth's crust by continued or episodic magma injection, and how growth and crystallization of these plutons drives metamorphism of the surrounding rocks and geothermal systems. The project will provide an opportunity to train students and young scientists in research that will have laboratory, computational and field components. The ability to view complex natural processes from multiple perspectives is key to the training of successful geoscientists.The need for improved data on temperature-dependent properties of rocks that can be incorporated into integrated thermal models is motivated by recent advances in understanding of how granitic plutons are constructed, and because intrusion-induced metamorphic and geothermal systems generally have longer durations than simple conductive and convective thermal models typically predict. There has been a paradigm shift from viewing plutons as large volumes of magmas that are emplaced in a single pulse as diapirs to viewing plutons as bodies that grow over extended periods, from tens of thousands of years to millions of years. Prolonged injection of magma has consequences for crystallization histories of plutons and duration of metamorphic-geothermal systems, all of which are controlled by heat transfer. The aim of the project is to determine temperature-dependent properties of minerals and rocks and to develop integrated numerical models for magmatic-metamorphic-geothermal systems. The modeling will be field-tested by examination of the growth of the Harney Peak Granite pluton in the Black Hills and how its growth influenced its thermal aureole. The laboratory data will be useful to workers who study processes in many other geologic settings.