Sedimentary Structures

Question 1

What is the difference between primary and secondary structures? List some examples.

Answer 1

Primary structures occur during deposition. Ex) Ripple marks
Secondary structures occur after deposition. Ex) Intrusion, deformation

Question 2

How are biological structures different in primary or secondary structures?

Answer 2

Primary biological structures are things like tracks and trails. They occur on the surface of the sediment.
Secondary biological structures occur below the surface, like burrows.