Optical Microscopy Systems and Video Display in Under- graduate Petrography Laboratories

岩石学中的现代实验室研究，即研究岩石的矿物学和结构，远远超出了传统的透射式光学显微镜方法。我们需要一个光学显微镜系统，以便将新的设备和技术引入我们的本科课程。该设备包括一个带有透射光和反射光系统的偏振显微镜，以显示所有三种类型的图像。阴极发光对矿物中的特定微量元素很敏感；它突出了连续晶体生长产生的微妙结构，这些结构在透射光中看不到，并允许快速识别某些矿物。反射光可以识别不透明的矿物并研究它们的相互生长。有了视频系统，我们可以极大地提高岩石学方法的教学效率和清晰度：我们都将同时看到相同的特征。另一种选择是与每个学生进行艰苦的互动，轮流在显微镜下观看一张图像。学生们将在一系列新的课堂练习和本科生研究中使用这些仪器。视频展示还允许在入门课程中进行指导性演示，以展示综合几种类型信息的重要性。

Modern laboratory investigations in petrography, the study of the mineralogy and textures of rocks, go far beyond traditional methods of transmitted light microscopy. We are requesting an optical microscopy system to bring new equipment and techniques into our undergraduate curriculum. The equipment includes a polarizing microscope with both transmitted and reflected light systems to display all three types of images. Cathode luminescence is sensitive to specific trace elements in minerals; it highlights subtle textures produced by sequential crystal growth that are not visible in transmitted light, and permits rapid identification of certain minerals. Reflected light allows identification of opaque minerals and study of their intergrowths. With the video system we can dramatically increase efficiency and clarity in instruction of petrographic methods: we will all be looking at the same feature at the same time. The alternative is painstaking interaction with each student, taking turns viewing an image in the scope. The students will use the instruments in a series of new classroom exercises and in undergraduate research. The video display also allows instructive demonstrations in introductory classes to show the importance of synthesizing several types of information.