Sites of geomorphological interest
The district of Beigua Geopark presents particularly remarkable peculiar geomorphological features.
The several block deposits
present on top of the Beigua massif are undoubtedly very important and they have always represented an extremely appealing element for researchers and excursionists.
The landscape of the higher slopes and the summit is actually characterised by the accumulation of large blocks whose heads have no rock faces as well as by some relic rock relief that attracted the attention of many geologists of the past.
Some researchers worked to study and identify the periglacial and the non-periglacial block deposits and they were able to understand both their origin and movement mechanisms. The characteristics of some openwork block deposits of the Beigua Massif present superficial forms, texture and morphological patterns similar to the features of "block stream"
. Many bodies (block field, block streams) have been identified; the block streams are always located along the valley floor with very steep slopes (10° -12°) while the block fields are present in very flat areas. Two extremely significant examples of these deposits can be observed at Prariondo (Sassello) hiking eastwards along the Alta Via dei Monti Liguri track (close to Bric Damè).
Another important site from a morphologic point of view – but also presenting an extraordinary value from the point of view of biodiversity of the area - is the Laione peat-bog
, a wetland on the Po side about three kilometres away from the divide, already preserved for the presence of different zoological and botanical endemisms. The peat-bog genesis is extremely complicated but, on the bases of the results of some recent surveys, it can be summarised as follows: the depression corresponding to the Laione (958 m) could be a paleovalley relic extending northwards and reaching the level ground of Pianpaludo (856 m).
Afterwards, tectonics carved this valley up favouring the phenomenon of fluvial captures and therefore the section south of Laione nowadays flows into the Nido brook, while the northern section flows into the Conca brook. Subsequently or simultaneously, strong periglacial processes originating the block streams that, during the last Wurmian glacial expansion, barred the peat-bog area shaped the isolated relic.
On the Tyrrhenian side there are other interesting geomorphologic sites where forms and processes testifying the present fluvial (embedded ravines and meanders) and gravitational (collapse landslides and clastic deposits) shaping are very evident. Besides, it is worth mentioning for their didactic importance the forms linked to the sea level variations, as the marine terraces
present along the coast strip between Arenzano and Varazze.