Welcome to Music Banter Forum! Make sure to register - it's free and very quick! You have to register before you can post and participate in our discussions with over 70,000 other registered members. After you create your free account, you will be able to customize many options, you will have the full access to over 1,100,000 posts.
For information on what metalcore is, go to the hardcore metal section here.
I'm not an expert, but here are some rough indicators on how I view different styles of hard rock and metal (those with relation to metalcore). See the previous link for information on the genres:
Hybrid Mode