Shandal Visual Lab
The principles of geology as animations you control: play, pause, change the conditions, answer the questions and download each scene as an image, PDF or video for your class.
- 1Watch the process unfold step by step, or drag the time bar.
- 2Change the conditions — the type of boundary, the spreading rate, the kind of unconformity — and see the result.
- 3Test yourself with the questions under every lesson.
- 4Download the scene as PNG, JPG or PDF, or record the whole lesson as a video.
Stratigraphy
How layers record time, and how to read the order of events in a cross-section.
Superposition and original horizontality
Why the oldest layer is at the bottom, and why tilted layers tell of later movement.
Lateral continuity and correlation
Matching layers across a valley, and where a layer ends.
Cross-cutting relationships and inclusions
Read the story of a cross-section: layers, a fault, a dike, erosion and a new layer.
Unconformities: gaps in the record
Angular unconformity, disconformity and nonconformity, built step by step.
Plate tectonics
What happens where plates move apart, collide or slide past each other.
Divergent boundaries: ridges and rifts
Sea-floor spreading with magnetic stripes, and a continent splitting into a new ocean.
Convergent boundaries: subduction and collision
The Andes, the island arcs of Japan and the Zagros of Iraq and Iran.
Transform boundaries
Ridge offsets and fracture zones in map view, and the Dead Sea fault on land.