In William Smith's footsteps: a modern take on regional stratigraphy
Summary
This activity uses modern Google Earth to view 3D geological cross sections from the British Geological Survey, in order to trace the units that formed William Smith's 'Map That Changed The World". Students use the interactive sections to examine rock type, depositional environment, palaeogeography, regional stratigraphic variations, deformation and geological history, and compare these to Smith's original map and cross sections for the southern part of the UK. It brings together the first ever geological map with 3D visualisation to embed a deeper understanding of the principles of stratigraphy, depositional environments, deformation and historical geology.
Context
Audience
This activity was designed for a first year introduction to geology unit. However it is suitable for lower levels (high school), and can be adapted to higher levels of undergraduate study, including courses in sedimentology, stratigraphy or regional geology. It is easy to include more of the BGS cross sections, or choose more complex areas of the UK to analyse, with or without accompanying rock specimens. The BGS database contains hundreds of 3D cross sections across all of the UK, including some areas of classic geology.
Skills and concepts that students must have mastered
Students should be aware of the basic principles of stratigraphy including the Law of Superposition, the principle of original horizontality and the principle of lateral continuity. Some experience of identifying basic sedimentary rock types in hand specimen is useful, especially if you want to include appropriate samples.
Students should also be familiar with, or encouraged to research William Smith, and "The Map That Changed The World". Students should be familiar with Google Earth.
How the activity is situated in the course
This is used as one activity of a first year practical class during a themed week called Geology of Continents. It brings together a number of basic concepts covered in preceding weeks. Students have studied basic minerals, the rock types and rock cycle, and covered basic deformation.
Goals
Content/concepts goals for this activity
The primary goals of this activity are to a) interrogate the interactive cross sections to understand the regional stratigraphic layering, lithologies and distribution, b) put this information into a regional context by describing the variations of key regional units in terms of thickness and extent.
Higher order thinking skills goals for this activity
Students will need to synthesize the information and formulate hypotheses as to the distributions of key units. This will include determining unconformities and their significance, reasons why certain units may be absent or terminate, and what the depositional settings would have looked like through geological time.
Other skills goals for this activity
Students will work in groups, tabulate all of their observations and hypotheses, sketch palaeogeographic maps, and give an oral presentation of their findings.
Description and Teaching Materials
The students need access to Google Earth. Geological cross sections from across the UK can be downloaded from:
https://geologyviewer.bgs.ac.uk/
For this exercise specifically related to the Smith map, I have chosen a subset of 9 ~N-S lines across the southern UK, but this can be adapted as needed. My sections included lines 180, 221, 236, 282, 317, 318, 241, 246, 283.
Students should also have access to either a digital or hard copy version of William Smith's map.
Students complete a series of questions and interrogate the interactive cross sections to populate a table of data. Students then synthesize their observations to sketch out palaeogeographic maps for various horizons and complete a geological history. In my labs I assign each group a unit or a series of related units for which they need to think about palaeogeographic setting and depositional environment.
William Smith's map (Acrobat (PDF) 6.5MB Dec1 24)
Data collation table (Microsoft Word 2007 (.docx) 14kB Dec1 24)
Student instructions (Microsoft Word 2007 (.docx) 4.4MB Dec1 24)
Teaching Notes and Tips
Be aware that some of the sections can only be viewed looking east, and appear dark when viewed looking west (and vice versa). I usually include a variety of rock types representing lithologies from the sections, as this provides a visual and practical aspect. Depending on the level of the class, you can go into depth about any aspect appropriate to your course. I focus on regional changes to the layering, why some layers disappear, others get thicker, where the faults are etc. You could expand this activity by including any other classic areas, for example the Moine Thrust, ring dyke complexes, the classic Welsh stratigraphic sections, accretionary complexes in Wales and Scotland, the Southern Uplands Faults - the list is endless.
I also talk to them about William Smith, how his map came to be, and how it was originally received.
Assessment
I usually make students give an oral presentation in the lab, rather than a submitted piece of work. This is due to the placement of the activity in the unit. It is more about consolidating basic skills learnt in previous weeks. I capture the palaeogeographic maps drawn on the whiteboard for further discussion in later weeks. Different groups have to comment on different units.
References and Resources
British Geological Survey Geology Viewer https://geologyviewer.bgs.ac.uk/
UK Onshore Geophysical Library https://ukogl.org.uk/william-smith/