a typical layer or group of layers (for example, of coal), the top or bottom layers of stratigraphic subdivisions, the boundaries between rocks with a different composition and physical properties, the surfaces of stratigraphic and structural disconformities, the surfaces of bodies composed of magmatic rocks, or surfaces that delimit ore bodies and deposits. Basic horizons are studied during geological research and exploration for minerals in order to identify the conditions of occurrence of rocks at depths and the shape and size of ore bodies and deposits. Drilling and the geophysical analysis of geological maps and cross sections are used to study the position of basic horizons. The structure of basic horizons is represented on structural and geological maps (with isolines) and in geological cross sections.
A. E. MIKHAILOV