Ok well given the fact you will be running a resonably heavy gantry at higher feeds then I may be inclined to go with servo's due to linear torque.

Other option is to use higher pitch screws 2020 so you can get the same speed at lower motor RPM. Obviously you will lose some resolution but do you need more than 0.01mm.? I think you won't for ice.
20mm will put the motor in a 450 RPM range where torque is strong for the same speed as 10mm pitch. Where with 10mm at 9M/min you will be in the 900rpm range where torque starts to drop away.

Also I think if you contact belt manufactures there will be belts than can handle the cold so you could either use servo's or steppers with higher pitch screws to increase torque with a ratio.