Depositional environments

The need to represent depositional environments in maps arose with F° 223 “Ravenna” made by the Region of Emilia-Romagna. For this sheet, area symbols using different colours for different environments were laid on top of the base colour of the synthem of origin. This approach respected the principle whereby the same base colour is used for each stratigraphic unit, but it did not use the texture colours provided for in the Quaderno, serie III, n. 2 – (although the SGN considered this the lesser evil). However given that the current decision to link texture colour to origin does not allow this criterion to be followed, an alternative solution was developed which will be used in the new sheets. In general, depositional environments will be represented using different shades of the colour used for the stratigraphic unit to which the various deposits belong, chosen from the shades in the SGN chromatic manual. Should it become necessary (e.g. when a large number of environments is involved) it will be possible to use the same colours banded with 2-mm wide sloping white parallel lines. The various shades will be overlaid by the texture area symbols using different colours according to the process involved, following the genetic criterion described above. This criterion will also be adopted for marine areas in order to create uniformity between emerged and submerged areas. It should be pointed out that the representation of depositional environments is optional and it is up to the operators to decide whether to add this type of information to the map. The coordination of the Area Committees is obviously required for the purposes of guaranteeing homogeneous maps. These are general guidelines and justifiable exceptions will be examined on a case by case basis.