Do you know which firms or organizations are big in your field ? You might be able to view some resumes on linked in
Here’s some names you might research and even contact if you peruse.
I imagine you can find lots in lots of geological majors involved.
As for multiple emails, profs are busy. Not all are engaging, and perhaps they are one and done.
You can keep trying.
Better might be on a school visit - even locally - ask admissions if they can set up a meeting with Dr So and So so you can learn more about opportunities at the school. Admissions is trying to sell you - a good AO will jump through hoops for you.
Good luck
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