GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.3 727 ( M R , D R , I R ). The program calculates automatically the induced magnetization vector, M I , and the total magnetization vector, M , by the following equations: (2) (3) Methods of forward modelling. Modelling of any specific archaeological feature by one of the basic ArchaeoMag shapes should start with a guess about the burial depth and with a characterization of the NRM component, which is predominant in most of the situations that can be studied by magnetic methods. The burial depth influences the lateral width of an Fig. 1 - Four examples of archaeological anomalies that can only be modelled by sources with a significant component of remnant magnetization. The magnetic profiles show observed and model anomalies (black and green lines, respectively), and the error curve (observed - calculated, in red) along selected traces (white lines). The buried objects arc indicated by black lines and white dots. Model parameters are listed in the object properties dialog boxes.A:Astrong dipole anomaly whose peak exceeds 620 nT, most probably a furnace (Powell et al. , 2002). B: AT - structure, probably representing a combination of a segment of a long and 2m large WNW-ESE oriented wall and a transversal smaller wall. C: A small cylindrical structure, 70 cm diameter by 20 cm height, characterized by a very anomalous inclination ( I = –85°) of remnant magnetization. D: A composite anomaly, resulting from the superposition and coalescence of the anomalies associated with three distinct buildings. The upper profile refers to the black trace oriented WSW-ENE. The parameters of the selected object (delimited by white dots) are listed in the dialog window. The northernmost feature has D = 30°, I = 5°, M = 1.8 A/m, while the western prism has D = 30°, I = 60°, M = 0.3 A/m.