I loaded into a world and the treasure map showed treasure   

a. Under the water (quite a way)

b. Dg around (You need to look lower than the map tells you I found it using fill command to get rid of gravel)

c. The location was not under sand but under gravel and stone instead

To experience:

1. Use seed -4786893271456824633
2. Go to the above ground ruins 
3. Follow the map 
4.  Try to find where it tells you