Skip to main content
Geosciences LibreTexts

2.2: Thin Sections

  • Page ID
    11103
  • Learning Objectives

    • Describe the parts of a standard thin section.
    • Describe the differences between a standard petrographic thin section, a thin section prepared for electron or ion microbeam analyses, and a thick section.
    • Describe the steps necessary to produce a standard thin section, in the correct order.

    Prior Knowledge and Skills

    None

    HomeWhat is a Thin Section?

    Figure 2.2.1. A thin section on a petrographic microscope stage.

    Figure 2.2.1. A thin section on a petrographic microscope stage.

    The general procedure for creating thin sections has remained nearly the same since the modern version was created nearly 200 years ago. In this section, we review examples of modern thin section making procedures.

    Guided Inquiry

    Figure 2.2.2. Interactive diagram showing different types of thin sections.

    The original version of this chapter contained H5P content. You may want to remove or replace this element.

    Question 2.2.1.

    The original version of this chapter contained H5P content. You may want to remove or replace this element.

    Question 2.2.2 An electron microprobe determines the composition of a mineral in thin section by comparing X-rays generated from a beam of electrons hitting the atoms within the mineral to a set of compositional standards. What is the difference between a “microprobe” thin section and a standard thin section, and why do you think this difference is necessary?

    Question 2.2.3 Thick sections are prepared for special analyses, such as fluid inclusion work (https://en.Wikipedia.org/wiki/Fluid_inclusion) or FTIR spectroscopic analyses which is sensitive to epoxy and glass, so the rock section must be removable from the glass and glue. How is a thick section different from a standard thin section?

    How are Thin Sections Made?

    Guided Inquiry

    Preparation in a University Lab:

    Use Hirsch, Dave (2012; Ret. 11/21/2018) How to make a thin section. https://davehirsch.com/other/thinsections/ to answer these questions:

    Question 2.2.4 What do you do to a glass slide to “frost” it?

    Question 2.2.5 What is a rock chip?

    Question 2.2.6 Why do the instructions say to grind one corner off the glass slide?

    Question 2.2.7 What should you do to the rock before you cut a slab out of it?

    Question 2.2.8

    The original version of this chapter contained H5P content. You may want to remove or replace this element.

    Guided Inquiry

    Professional Preparation: Watch these videos from Spectrum Petrographics, a professional thin section and petrography company, about how they create thin sections:

    Thumbnail for the embedded element "Thin Sections ft. Spectrum Petrographics: Welcome to Spectrum"

    A YouTube element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/petrology/?p=44

    Thumbnail for the embedded element "Thin Sections ft. Spectrum Petrographics: Behind the Scenes"

    A YouTube element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/petrology/?p=44

    Question 2.2.9 Why does Spectrum Petrographics put quartz grains in the rim of each thin section billet?

    Question 2.2.10 How does Spectrum Petrographics label the glass slides?

    Question 2.2.11 Approximately how thick is the section after it is initially cut in the cutoff saw?

    Additional Resources for Learning to Make Thin Sections

    A screenshot of a video on how to use the rock saw
    Figure 2.2.3 Screenshot of rock saw video.

    If you are interested in more detailed descriptions of the thin section equipment and steps to make thin sections, please see the following resources:

    Return to Table of Contents