Dear Sir,
As per FMC150 user manual Table 2, external clock input bandwidth is 3-800MHz so 10MHz should be fine. You might want to check A/D datasheet to know whether or not the A/D chip can have such a low sample clock.
Stability/quality of the clock have a direct impact on the acquisition (jitter, etc..) so an extremely good signal quality should be used for the clock. Normally you need to have expensive filtering otherwise effective number of bits will be affected.
I hope that helps,
Arnaud