"a sample of post apocalyptic fiction is"
- A good clean* introduction would be: When the Tripods Came by John Christopher
- A more serious, thoughtful and longer example: The Children of Men by PD James
- Easy 'airport' reading: Without Warning by John Brimingham
- A fascinating but harrowing read: Oryx and Crake by Margret Attwood
"post apocalyptic bible"
The first thing that comes to mind is a special study bible that emphasises the post-apocalyptic! (Some Study Bibles: NIV Study Bible, lots of notes and very popular but a bit bland. ESV Study Bible very pretty to look at, good if you prefer the ESV translation. Spirit of the Reformation Study Bible: My favorite which as you'd expect has notes that are theologically focused on reformed theology.)
"was it a comet or asteroid road cormac"
The Road by McCarthy Cormac is set after a massive devastating apocalypse of some sort. Cormac leaves the disaster ambiguous however the two most likely scenarios are a large nuclear war or a comet/asteroid strike, both of which would cause nuclear winter and have global ramifications.
The lack of radiation and the washed up boat both suggest a 'natural' disaster. However the lack of widespread water damage the intact beach intact combined with references to the riots and breakdown of society suggest a some sort of nuclear war or other more inexplicable event. Interestingly there isn't a reference in the story to a sudden civilisation altering event.
*Clean = no sex and limited violence.