Geo Teams:
I suspect that they can only increase accessability now. No new mineral finds are being made, and teams with below 140 skill will complete a survey without doing anything or increasing their skill. +140 teams can increase their skill however.
The Tritanium amount in the image below shows such an accessability increase(from 0.4 to 0.7) but no new minerals.
edit: The team in question did not increase its skill from getting that accessability increase, though it has previously.
edit2: the team managed to make a mineral find on venus, and its skill went up for it.
edit3: had a skill increase for finding nothing on Mars.
edit4: Alright, I've seen a < 140 skill team skill up, so the geo teams probably are working as intended.