Hey, I'm not sure what "separated" means but typically the lower end of the mast
erodes due to corrosion
from the bilge water
. The mast step itself also corrodes and the two lag screws in the mast step usually get it worse still.
If your mast is in great shape you may want to pick up a new mast step, and replace the lag bolts. You may need to move up to larger bolts, or clean/fill the holes etc. Here is a place to get a new mast step.
Search for pearson
on that page and you'll see your step pretty quickly.
If your mast is corroded you may need to cut some of it off and install a riser base for the mast step. This allows you to get rid of corroded aluminum
and also get the mast/mast step out of the bilge water
. I recently did this on my pearson
28-1 and have a few photos so that you can see one approach.
Poolio's sailing and travel blog. : Mast riser base for Pearson 28-1
There are a lot of ways to approach this more extensive repair but hopefully you won't need to get into trimming the mast etc.