Geology and soils in Vierville-sur-Mer
Extract from the IGN card at 1/25000
(details) IGN card at 1/25000, whole of the municipality
Illustration mentioned in the fund, but absent from this copy: CarteGeoPerceeCollevilleP.jpg (document absent from this copy)
(Details) for the record the geological map of the site and its explanatory note
The geological map drawn by Arcisse de Caumont in 1825 at the beginning of the 19th century, when he was apparently 23 years old.
And consult the site:
https://patrimoine.mines-paristech.fr/Cartes_geologiques_XIXe
Arcisse de Caumont map details
Our cliffs, seen by A. de Caumont
Paleo environment at the time of the glacial maximum, 20,000 years ago
1895 and 20th century
Above, the geological section, between Formigny, Louvières and Vierville. The valley is that of the Véret (sketch by Eugène Hausermann around 1895)
(details) Geological map at 1/80000, (old) extract
Geologically, the Bessin region is a contact area between the sedimentary soils of the west of the Paris basin and the land of the Precambrian, of the eastern limit of the Armorican massif, present in the Norman bocage.
The subsoil is made up of calcareous layers that alternate with clayey or marly layers.
Vierville-sur-Mer is part of the Paris Basin which has a subsoil consisting of Jurassic age geological formations with a predominantly limestone covered by superficial formations.
The municipality is first based on the formation of the "Marnes de Port en Bessin" (j2a, Lower and middle Bathonian, in dark orange) visible on the seafront, on which the formation of the "Calcares de St Pierre du Mont" (j2b, medium Bathonian, in light orange) was deposited.
Quaternary formations, more recent, have come to cover a large majority of the municipal territory: they are mainly plateau silts (LP) which are deposits of Aeolian origin that were brought by the polar winds during the glacial periods of the Quaternary.
Excerpt from the geological record associated with the old map at 1/80,000
A. Movable formations due to periglacial solifluxion. These silts are of very complex formation in terms of their composition: on the one hand they come from the alteration of the underlying rock, but also a part derives from a loessic origin; at the base there is a "head". These silts cover the terrace of the Bas Normannien.
a1b. Limons of the trays. The extreme abundance of precipitation and the low thickness of deposits has generally left only lehms. The distinction between these lehms and the products of the decomposition of the underlying rock is sometimes difficult.
jII. Medium Bathonian. it is formed of coarse limestone, in thick banks of about thirty meters of power, where beds of blond flint are interstratified; no fossils have been reported. They are well exposed in the cliffs between Pointe de la Percée and Grandcamp.
jIII. Lower Bathonian. These are marls and gray clays (Marnes de Port-en-Bessin on the Caen leaf) whose power reaches 50 meters. Fossiliferous towards the base: there are two fossiliferous banks of marly and hard limestone, containing oppelia aspidoides, Morphoceras pseudo anceps, Belemnopsis bessinus, Good outcrops are formed by the cliffs, from the Pointe de la Percée towards the East.
The geological map at 1/50000, extract from Port en Bessin à la Percée
Legends
Pedo-geological study of a plowing area intended for spreading manure, (island 1 south of Vierville, on the map below)
