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

该奖项由 2009 年美国复苏和再投资法案（公法 111-5）资助。地球内部的大多数地质过程都是由热传递驱动的。这些过程包括岩浆生成、火山作用、地热系统以及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设岩石的几个基本特性为固定值，例如热容量（即岩石保持热量的能力）、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特性的值，特别是它们如何随温度变化，仍然知之甚少，研究的一方面集中在实验室的实验测量上。然后，新的值将应用于通过持续或间歇性岩浆注入来模拟地壳内特征明确的岩浆体的生长，以及这些岩体的生长和结晶如何驱动周围岩石和地热系统的变质作用。该项目将为学生和年轻科学家提供实验室、计算和现场研究培训机会。从多个角度观察复杂自然过程的能力是训练成功的地球科学家的关键。对可以纳入综合热模型的岩石温度相关特性的改进数据的需求是由对花岗岩岩体如何构造的理解的最新进展所推动的，并且因为入侵引起的变质和地热系统通常比简单的传导和对流热模型通常预测的持续时间更长。范式发生了转变，从将岩体视为在一次脉冲中形成的大量岩浆作为底辟，转变为将岩体视为在数万年到数百万年的较长时期内生长的物体。岩浆的长时间注入会对岩体的结晶历史和变质地热系统的持续时间产生影响，所有这些都受到传热的控制。该项目的目的是确定矿物和岩石与温度相关的特性，并开发岩浆-变质-地热系统的综合数值模型。该模型将通过检查布莱克山哈尼峰花岗岩岩体的生长及其生长如何影响其热光环进行现场测试。实验室数据对于研究许多其他地质环境中的过程的工作人员将很有用。

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.