- The Territory -
Brief geological history of the Sorrentine Peninsula
by Salvatore Palomba
- Part II -
It is only at the beginning of the Miocene period (23-7 million years ago) that the now deformed and overlapping cretaceous sediments returns to a marine environment. The sea, initially shallow, rapidly tends to deepen, lithotypes from areas not yet submerged are deposited (form sediments) on the cretaceous limestones forming a progressively deeper marine succession.
We therefore have a sedimentation characterised first by rough sediments, in a neritic marine environment (shallow sea), followed by progressively finer sediments common to a rapidly deepening marine environment.
In the Sorrentine Peninsula, in fact, the Miocene succession is characterised by a calcarenite graticule containing typical fossil remains such as mineralised oyster shells, selachian teeth clearly visible in a number of points of the Gulf of Salerno, followed by coarse sandstones which become finer as they rise to become clays in the highest section of the succession.
In this phase, in which horizontal tectonic movements are prevalent, sediments accumulated in the ocean over tens of millions of years, compressed between the two converging continental masses, move and overlap in increasingly complex forms.
The more flexible sections fold and separate; in the strata stack the higher sections slide to overlap the lower, covering rock of the same age or younger, in such a way that the older rock overlays more recent rocks to produce mountain chains characterised by typical overlapping faults.
Examples of this kind of phenomena are also present in the Sorrentine Peninsula, the clearest example being the cretaceous limestones of Monte San Costanzo at the western tip of the peninsula which cover the Miocene sandstone sediments; the phenomenon is plainly visible in the bay between Punta Vaccola and Punta San Lorenzo.
To a lesser extent, similar situations are evident in many other locations of the peninsula, localised above all via bores performed for geognostic surveys, well digging and water searches.
Returning to the subject of Sorrentine Peninsula geological history, at the end of the Miocene period we can say that the Apennine chain structure is complete, although its current form and dimensions are not yet apparent.
Formation will be completed during the Pliocene period in which horizontal movements will prevail.
At the end of the Pliocene period the Sorrentine Peninsula has in fact almost assumed its final structure; the contours of the Monti Lattari are practically those recognisable today from Punta Campanella-Monte San Costanzo to the peaks of Monte Faito.