The Adelaide Hills has a diverse, ancient geology.
The Adelaide Rift Complex (or Adelaide Geosyncline) stretches from the Flinders Ranges via the Barossa Valley and Fleurieu Peninsula through to Kangaroo Island. It is estimated that its sediments were deposited between 500 and 870 million years ago.
The geography and climate of the region has contributed to soils that are highly variable in structure and chemistry.
However, in general terms, they can be described as a mixture of sandy loams, loams and clay loams over clay subsoils. These vary in structure and it is not unusual to find these soils combined with shale and ironstone.
They are generally acidic, in some cases neutral in pH, but rarely alkaline.
Soil depth is also variable due to topography, which can range from steep slopes to undulating hills, resulting in shallow stony soils to the top of hills and deep peat-like clays at the bottom of hills.
The variation in topography and soil type can affect vine growth, and contributes greatly to wine style. Low lying areas with heavy soils provide potential for greater vigour, while higher well drained stony soil allow better vigour control, both of which can be utilised depending on the variety and wine style required.