Distinction between textures and meaning of colours
Distinction between textures is currently only foreseen for
alluvial deposits. The general guideline states that the
distinction between textures should also be applied to aeolic,
lacustrine, palustrine and emerged marine (eg. deltic, beach, tidal
plain) deposits.
If preferred, it is possible not to distinguish between textures
for lacustrine, palustrine and deltic deposits, using the generic
symbol described in the Quaderno, serie III, n. 2.
The textures are as follows: gravel, sand, silt /loam, clay and
peat. The polymodal granulometric distributions must be represented
by the combination of elementary symbols (no longer two).
For glacial deposits the symbology described in Quaderno, serie
III, n. 2 and subsequent additions is valid.
In ordert to make the maps easier to understand and read, the area
symbol’s colour will be the same as the one used for the
deposit origin.
The base colours (taken from the SGN chromatic manual) are as
follows:
- slope deposits caused by gravity — red
(PANTONE WARM RED)
- fluvial, fluvioglacial and slope deposits caused by scouring
— blue (PANTONE REFLEX BLUE)
- glacial deposits — violet (PANTONE
VIOLET)
- marine deposits (emerged and submerged) — light
blue (PANTONE PROCESS BLUE)
- lacustrine-palustrine deposits — green
(PANTONE GREEN)
- aeolic deposits — bistre (PANTONE
1395)
- deposits of anthropic origin – grey
(PANTONE COOL GRAY 10 or NERO)
The travertine will continue to be identified by the horizontal
blue pattern (PANTONE REFLEX BLUE)
It should be pointed out that the coordinated use of patterns
for textures and colours used for the origin makes it possible to
identify those deposits for which no specific symbol is foreseen.
For example, a loess will be represented with a bistre (aeolic)
silt texture, while a fluvial-lacustrine delta deposit will be
identified by a green (lacustrine) sand and/or gravel texture.
Specific descriptions in the legend will make it possible to
describe the deposit in detail.
The use of area symbols to identify the type of deposit and the
texture (when forseen) should be applied in case of legends
organised according to UBSU (the
criteria that should be followed, as reiterated above), given that
a synthemic unit, characterised by a single base colour, can
contain several types of deposit. The application of area symbols
is not indispensable in the following cases:
- when the synthemic unit is characterised by homogeneous
lithological deposits (eg. a synthem formed exclusively by fluvial
gravel);
- when the synthemic unit is completely divided into
lithostratigraphic units of different hierarchical ranks, each with
its own colour. The same obviously applies if only
lithostratigraphic units are used rather than UBSUs (although this
should be avoided, especially for sheets where mapping is still
underway).
In the case of legends organised according to the
lithostratigraphic criterion, deposits of the same type (eg. slope
deposits) but with different ages are to be represented using the
same area symbol applied over the corresponding colour fields.