Which of the following is NOT a sedimentary structure?

A. Magma emplacement

B. Cross-beds

C. Mud cracks

D. Ripple marks

Magma emplacements are not sedimentary structures.

The correct answer is A. Magma emplacement.

Magma emplacement is not a sedimentary structure. Sedimentary structures are termed as features which are being formed during the time of deposition. Sedimentary are being characterized by the way of bedding which is known to occur when different sizes of particles are being deposited on top of each other.

Examples of sedimentary structures include, ripple marks, graded bedding, and cross bedding, mud cracks.

Ripple marks which are symmetrical are found in the beaches and the ones which are asymmetrical are found in the wind which is found in the desert or in a river.