Service Entry Wire/Ground Location (100 amp service)
You'll have to use a cable or wires that are rated for wet locations. You'll most likely use Underground Feeder (Type UF) cable, Underground Service-entrance cable (Type USE) , or THWN wires.

You'll have to install a proper grounding electrode at the cabin, and bond the grounding conductor to it. 

You'll have a grounding electrode at the pole, where you'll bond the service neutral and the equipment grounding conductor. From there you'll run four wires (two "hots", one neutral, and one ground), and you'll keep the ground and neutral separate.