If you're trying to generate electricity by exploiting a difference in two temperatures, it would probably be more cost effective to just drop a cable into the ocean.
What actually matters is the temperature difference between two points.
But to answer your question, sure, probably - assuming your materials can withstand the extreme heat, and assuming you can get at it, which as sp332 pointed out here (http://news.ycombinator.com/item?id=3708465), we can't.