Are assets parked in an irrevocable trust also considered marital property?

It depends on when you establish that irrevocable trust.

If you establish that irrevocable trust prior to marriage using non marital assets, then maybe they get protected.

But if you have a marital asset that you earned during the marriage and now you transfer it into an irrevocable trust for the purpose of saving it from your marriage and saving it in a divorce.

That might not work.

So it really depends on when you establish that irrevocable trust and whether it's pre marital or marital property going into that irrevocable trust.