The Geological Map of Italy 1 250'000 scale
The Geological Survey of Italy (now ISPRA - Land Protection and Georesources Department) has realized, in the occurrence of the 32nd IGC, a geological map of Italy at 1:1,250,000 scale based on the re-elaboration of a geological map prepared by the same workgroup to the scale of 1:500,000.
The innovation of the new 1:1,250,000 geological map of Italy is mainly the elaboration of the useful cartographic products so far formed for the Italian 1:50,000 geological cartographic project (CARG), subject of new geological field works. In areas not yet covered by geological surveys of CARG, data were recovered by the previous 1:100,000 national geological cartography or by recent geological maps from literature.
For this map were adopted original criteria, based on:
- main orogenic cycle subdivision;
- geological events.
Particularly, for sedimentary rocks, legend was organized based on a litho-chronostratigraphic subdivision related on a regional scale event, whether geodynamic or biologic, and subdivided in paleogeographic environments.
Volcanics, subdivided on a chemical or petrogenetic affinity level, have been also grouped on the basis of the paleogeographic domains affected by magmatic episodes with geodynamic meaning. The age of emplacement has been considered an important distinctive criterion for those volcanics, belonging to these groups, showing the same chemical features.
Further on, regarding plutonic rocks, we have distinguished them in two main categories on the basis of the age of the emplacement, in turn grouped by general petrochemical features related to decreasing magma evolution.
Finally, concerning metamorphic rocks, we made a first distinction on the basis of the age of the metamorphic event. Then, we have grouped these rocks by metamorphic degree and eventually by the high-pressure features; when the protolithes is recognizable it is assimilated to the parent rock.
The goal of this work is the compliance of a great number of rock formations combining them by the same tectonostratigraphic event meaning.
The result is a new conception of synthesis “geological map” in which is possible to identify evolutionary geodynamic significance in addition to the conventional lithological connotation.
The synthesis procedure allowed us to put in evidence areas and thematics in which to develop careful studies for a better comprehension of Italian geological history.
