Assuming you had a layer of peat over your site with varying thicknesses you would need to start a new drawing and create a point group with the borehole/trial pit locations as the East/North and the peat/stratum thickness as the Z value (needs to be positive)
Create a surface (Peat Depths) from this point group and add other points as necessary based on site knowledge/judgement to cover the ground survey you have
Shortcut the original ground topo survey into this drawing
Create a Volume Surface with the Peat Depths as Base and original topo as Comparison - call it VS Inferred Peat Horizon
Create a new surface called Inferred Base of Peat and paste the Volume Surface in - this can now be used as a regular surface for profiles sections etc etc. but check the levels reported at the borehole locations (OG Level less Base of Peat level) with the recorded depths of peat to see if it has worked.
You can also tweak the Peat Depths surface to add areas where the peat may be absent etc and add additional depth data to the surface which will dynamically update the Inferred Base of Peat surface
Access a broad range of knowledge to help get the most out of your products and services.