Macro to fill one table of data from another based on % of soil type

Hi,

This is a bit of a long shot. I'll try explain quickly

1) I have two tables - Sampler and Geology
2) Geology table has column "Soil" which is filled from some software Sampler table does not
3) I want to populate Sampler table (column soil) from Geology table based on matching depths
4) If a push has more than one soil type in then I want it to take the most dominant soil.
i.e if it was 20% Clay and 80% Sand I'd want it to be called sand.

Any help would be greatly appreciated