Following the deposition of a sequence of sedimentary rocks, which event is the first to occur to produce an angular unconformity?

Answer: To develop an angular unconformity, the following steps has to be taken place-

Firstly, layers of different pre-existing rocks must be present. The layers then gets tilted in any direction. Erosion occurs on the tilted bed. Lastly, recent sedimentary particles gets deposited, maintaining an angular relationship.

This is how angular unconformity is formed.

Hence, the first step initially required to form an angular unconformity is the tilting of the previously existing rocks.