Definition - What does Geology mean?
Per general definition, geology refers to the earth science consisting of the study of solid Earth, the processes in how it changes and the rocks by which it is composed.
For wine, geology is one of the main factors which make up terroir. The geology and/or earth and its components where a vineyard grows will have an impact on the type of grapes selected and the characteristics which will form.
WineFrog explains Geology
The geology of a vineyard site is a factor considered by viticulturists when deciding which grapes may be grown and how they are to survive. A cross-section of the soils are often examined to determine the type or types of soil found below the topsoil. It is essential to obtain such information to determine the mineral and nutrient level of the soil to ensure the survival of the vine.
The geology of a vineyard site is a subject used to describe how a wine obtains certain characteristics, based on its specific region.