How are these inputs transformed into new compounds?

Mineral component

Stones/gravel is greater than 2mm in diameter. The mineral component of a soil can be fractionated into 3 particle-size classes:

Sand (Coarse Sand 2-0.02mm,
Fine Sand 0.2-0.06mm),
Silt (0.06-0.002mm) and

Clay (below 0.002mm).

Sand and silt particles are largely unaltered by chemical weathering. They are chemically the same as the mineral material in the parent rock.

Clay-sized particles have already undergone one phase of chemical weathering to go from a ‘primary mineral’ to a ‘secondary mineral’. In the clay size range there are different materials (silicon, iron, aluminium, magnesium, potassium and calcium), but we will concentrate on the aluminosilicate clay minerals. All clay minerals are composed of sheets of interlocking silica that alternate with sheets of aluminium oxide.