|OTHER PRIMARY ROCK STRUCTURES|
|There are a number of other primary structures that may be useful in distinguishing between layered sedimentary and layered volcanic rocks.|
|FEATURES FOUND IN SEDIMENTARY ROCKS|
The back-and-forth motion of waves in shallow water throws the bottom sediment into a series of ripples.
Similar looking ripples appear on the surface of solid rock. How did they form?
Drying mud forms a network of cracks.
Similar looking cracks appear on the surface of solid rock. How did they form?
A sand dune has been excavated for commercial purposes. Sets of inclined, parallel layers intersect each other at distinct angles. (Geologists call this 'cross bedding'.)
Similar looking structures appear in solid rock. How did they form?
Shells lie scattered along a beach.
Imprints of shells appear in solid rock. How did they form?
|Here's an explanation of how ripples might be preserved in rock:|
|FEATURES FOUND IN LAVA FLOWS|
Here's an explanation for columnar jointing:
|To check your answers and get additional hints and information, click on the link.|