# 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.

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.

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.

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

# Questions

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