[ It makes sense that one's maturity level matches one's lifespan - someone who will live hundreds of years likely wouldn't be entirely an adult before their first century. Not that Magneto knows this applies to Alec. He's just amused. ]

Teach. Research - same as any other degree in the sciences. Also geology is the basis for studies of oceanography and astrophysics. Environmental sciences and engineering as well. Or working with paleontologists. It's actually a broad field.