30 Plunging Folds

Elizabeth Johnson

What is a Plunging Fold?

A plunging fold is a fold that is tilted downwards in space, parallel to the fold hinge plane.

Figure 26. Plunging anticline (left) and plunging syncline (right). The interactive diagrams are linked below.

Interactive SketchUp diagram of a plunging anticline:

https://3dwarehouse.sketchup.com/embed/6cdfda2db2406141f0a2f88f187c27f1

Interactive SketchUp diagram of a plunging syncline:

https://3dwarehouse.sketchup.com/embed/eed7e3f10e065481f0a2f88f187c27f1

 

Plunging Anticline

Figure 27 shows a plunging anticline.  The direction the fold is plunging into the Earth is represented by an arrow in the map view.

Figure 27. A plunging anticline. Older rocks are in the center of the fold in map view.

3D interactive model of Figure 27: http://app.visiblegeology.com/model.html#ahFzfnZpc2libGUtZ2VvbG9neXIPCxIFTW9kZWwYme-rmQEM

Plunging Syncline

Figure 28 shows a plunging syncline.  The direction the fold is plunging into the Earth is represented by an arrow in the map view.

Figure 28. A plunging syncline. Younger rocks are in the center of the fold in map view.

3D interactive model of Figure 28: http://app.visiblegeology.com/model.html#ahFzfnZpc2libGUtZ2VvbG9neXIPCxIFTW9kZWwYyYLTlgEM

 

Questions

Figure 29. Folds for Questions 14-16.

3D interactive model of Figure 29: http://app.visiblegeology.com/model.html#ahFzfnZpc2libGUtZ2VvbG9neXIPCxIFTW9kZWwY2dDTlgEM

Question 14. What type of fold is “1” in Figure 29?

  • Plunging anticline
  • Plunging syncline

 

Question 15. In which direction is fold “1” in Figure 29 plunging?

  • Towards the north
  • Towards the east
  • Towards the south
  • Towards the west

 

License

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Physical Geology Laboratory by Elizabeth Johnson is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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