Lesson 5 overview
==================

This week we will be introduced to the equations that govern the flow of viscous materials.
At depths greater than those where rocks deform in a brittle manner, crustal and mantle rocks can be treated as viscous fluids with very high viscosities.
Ice also behaves as a viscous fluid in glaciers, which will be further explored in :doc:`this week's exercise <exercise-5>`.

1. :doc:`Rock and ice as viscous materials lecture slides <rocks-ice-viscous-fluids>`
2. `Gemmer et al., 2004 - Modelling salt tectonics <https://dx.doi.org/10.1111/j.1365-2117.2004.00229.x>`__ *(optional)*
3. :doc:`Notes on viscous flow down an incline <viscous-flows>` *(optional)*
4. :doc:`Theory for Exercise 5 <exercise-5-theory>`
5. :doc:`Exercise 5 <exercise-5>`

Learning objectives
-------------------

After completing this week's lesson you should be able to:

- State what a fluid is and how its flow is related to its viscosity
- Explain why geological fluids deform in a nonlinear fashion
- Model the flow of ice in valley glaciers using viscous flow equations

Lesson videos
-------------

.. admonition:: Lesson 5.1 - Rocks and ice as viscous materials

    .. raw:: html

        <iframe width="560" height="315" src="https://www.youtube.com/embed/OHDCUkB6cD0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
        <p>Dave Whipp, University of Helsinki <a href="https://www.youtube.com/channel/UClNYqKkR-lRWyn7jes0Khcw">@ Quantitative Geology channel on Youtube</a>.</p>

.. admonition:: Lesson 5.2 - Overview of Exercise 5

    .. raw:: html

        <iframe width="560" height="315" src="https://www.youtube.com/embed/bFCrjD9EY0U" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
        <p>Dave Whipp, University of Helsinki <a href="https://www.youtube.com/channel/UClNYqKkR-lRWyn7jes0Khcw">@ Quantitative Geology channel on Youtube</a>.</p>