How are subcultures formed?

How are subcultures formed?
i have to do a 5000 word essay on how and why subcultures are formed. so far i have 400 words. its would be great if someone could tell me HOW subcultures form and possibly some links. thanks 🙂

WARNING: [Opinion based answer only]

Suppose there’s a MAIN group of people with similar interests which has been in existence for a long time. It may have not been a culture in its own right but rather a group of people who have certain interests which classified them into a culture. Over time their interactions, ideas and/or way of thinking has been engrained in the different generations of people that have seen that group progress into something more. More likely they are a part of society and they don’t seem so foreign in a social kind of way.

Now, say a person from the group is discontent for some reason about the MAIN group. Or he/she wants to improve it. But that would mean changing the MAIN group into something that isn’t itself anymore. So it is disallowed by most members of the MAIN. He/she finds other people (supposedly from the MAIN group) that share their ideas and thoughts and change/rewrite/improve the original ideas of the MAIN group. That would form the basis of a SUB group with ties to the MAIN group due to any similarities in their ideals. And thus a subculture is formed.

Say for example: The Goth subculture
It began in England during the early 80s in the gothic rock scene, an offshoot of the Post-punk genre. Now (I believe), goth is a culture on its own and has branched out into different subcultures. For example; Steampunk and Lolita.

All of this just came off the top of my head. But I think its reasonable enough.