I have no idea what caused this crash, but here is the report

The game crashed whilst there was a severe problem during mod loading that has caused the game to fail
Error: net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from Quark (quark)

If you want the full report just ask. I am new to this. This is with the latest version of quark at the time of writing.

You need to post the full crash, yes. Put it on pastebin or gist.

Update Forge.