Underpressure damage
Introduction
In archaeology, excavation is the process of analyzing the natural and anthropogenic stratigraphies that settle in a certain place. The excavation process consists of removing the deposits in the reverse order in which they have been formed. For this reason it is necessary to understand at all times during an excavation: 1. the limits and nature of the deposits that make up the stratification; 2. the formative processes that have given rise to these deposits; 3. the order or sequence relative to which the deposits have been formed.
As it is a destructive activity (that is, each time an excavation is carried out, the original position of the deposits is removed and destroyed) it is necessary to carefully document and record the different elements that make up the stratification of a site.
Until a few years ago, only strata, constructions and other elements endowed with materiality were taken into consideration in archaeological documentation. Based on the contribution of Edward Harris, the category of Stratigraphic Unit has been introduced to define both the stratigraphic actions that involve a contribution of matter (positive Stratigraphic Units), and the contribution of the same (negative Stratigraphic Units).
Archaeological objects are only significant depending on the archaeological deposits in which they are contained, in such a way that the purpose of the excavation is not to recover buried remains - buildings, objects or vestiges of human activities - but to construct a stratigraphy based on the stratification that gives meaning to these objects.
It is first necessary to distinguish the type of site that is to be excavated. In general, one can distinguish between places of habitation and places of burial; Sometimes, rooms and graves appear intimately linked. Cave sites must be studied as a separate case, due to the special way in which work sometimes has to be carried out.
Excavations in habitation sites
In ancient populations, remains from different periods often exist in the same place, so it is necessary to specify whether stratigraphy exists. The cases of Hisarlik Hill are famous, with its overlapping of 10 towns with remains of all of them; that of Susa with its three cities, etc.
Such complicated overlays are not offered often. In any case, whenever there are objects that do not seem to fit into the same historical period, it is advisable to determine if they all appear at the same stratigraphic level, if there are differences in coloration depending on depth, etc. The best method to not lose any of these observations is to previously open deep and narrow trenches that reach the virgin earth and will provide a living section of the site.