It is a vertical section of soil, extending from the surface to the depth, taken in such a way as not to compromise the physical properties and morphological characteristics of the original soil horizons (such as colour, structure, stoniness, porosity and roots).
How is it made?
Once the soil to be sampled has been selected in the territory, the section is taken by undisturbed sampling techniques and then consolidated through impregnation procedures with resins or varnishes.
What’s it for?
The realization of monoliths allows to bring sections of soil in the museums, in the classrooms … They are authentic testimonies of the landscape, to be touched by hand and preserved over time.
What does it represent?
The exhibited monolith is representative of the stratigraphic succession of pyroclastic soils and deposits of the Somma-Vesuvius, from the Neolithic to the last Vesuvian eruptions. The cyclical nature of the phases of formation and burial of volcanic soils is demonstrated in the monolith by the alternation of pedological horizons and eruptive levels.
Some intervals have not been sampled to limit the size of the monolith and represent the most significant soils.
Meaning of some “soil horizons”
A- is a surface horizon, composed of both mineral and organic fraction. The latter is the product of plant growth and decomposition of biological substances by microorganisms, worms and other small soil animals. This horizon is intensely altered and mixed by roots and pedofauna; when it is cultivated it is indicated by Ap.
B – is a depth horizon that is formed by processes of alteration of sediments and rocks, or by migration of materials (clay, iron oxides, carbonates, humus) from the surface to the deep parts of the soil.
C- is a horizon relatively uninterested in processes of alteration of both chemical and biological nature (that of organisms). The original structure of the sediment is almost completely unchanged.
Various suffixes are used in the profile description in order to better define the characteristics of the soil horizons.
They are present in this monolith:
b – this symbol is used for mineral soils and indicates buried horizons identifiable with main genetic figures that developed before burial.
w – this symbol is used to indicate in situ alteration of horizon B of alteration
For description and sampling purposes, when a horizon has a considerable thickness and a certain vertical variability, it is possible to make subdivisions. Each sub-horizon is designated with a progressive number from top to bottom.
PHASES OF ON-SITE COLLECTION OF MONOLITHIC SECTIONS
IMPREGNATION AND RECONSTRUCTION PHASES OF THE MONOLITH IN THE LABORATORY