**1. Introduction**

The term Pontine Plain generally refers to the flat territory of Lazio between Terracina, Anzio, Circeo, and the Lepini Mountains obtained through reclamation of the Pontine Marshes in the 1930s. The history began more than two thousand years ago with the ancient people of the Volsci and ended in the first decades of the twentieth century with the "integral reclamation" of the 1930s (**Figure 1**) [1, 2]. As shown in **Figure 2**, the northward motion of the Adriatic Plate is affected by the interaction with the African Plate, which pushes from the south, and also by that of the Aegean Microplate, which moves toward the southwest at high speed [3]. The tectonics of Italy has shaped its morphology, especially the Apennines and Alps chains. Conversely, the Italian Plains (e.g., Po Plain and Pontine Plain) formed during the recent period of Pleistocene climate variation. The Roman area of interest lies between the Apennine chain and the Tyrrhenian Sea. The Apennine chain is a complex structural unit, with a series of thrusts toward the E–NE that formed mainly between the upper Miocene and lower Pliocene. Following the tectonic shortening

#### **Figure 1.**

*Recent geological map of the study area 1:1000000). From project CARG Piana Pontina. North arrow like in Figure 3.*

#### **Figure 2.**

*Main structural and tectonic features of the central Apennines and the peri-Adriatic zones: (1) Ligurian and southern Alps; (2) Foredeep basins; (3, 4) axial and outer belts of the northern Apennines; (5) Latium–Abruzzi and southern Apennines carbonate platforms; (6) outer belt of the southern Apennines; (7) Dinarides carbonate platforms; (8) Adriatic foreland; (9) Calabrian arc; (10) compressional features: A = outer front of the Alps and Apennines; b, c = active and inactive thrusts, d = fold axes; (11) Transcurrent and extensional features: A, b = active and presumably active strike-slip faults; c = normal faults. Scale 1:1000000 (modified from [3, 4]. North arrow like Figure 3.*

phases, the internal sector of the chain underwent a progressive process of extension toward the west with the formation of the Tyrrhenian back-arc basin. In particular, the Lazio anti-Apennine south of the Tiber is composed of the anti-Apennine volcanic zone with the Alban Hills, an isolated group that retains traces of volcanic activity including various solfataras. Southeast of the Alban Hills, the topography rises into the Lepini Mountains, and further south into the Ausoni and Aurunci Mountains [3].

*Introduction to the Sedimentary Geology, Genesis, and Evolution of the Pontine Plain in Relation… DOI: http://dx.doi.org/10.5772/intechopen.111683*

#### **Figure 3.**

*Geological-structural scheme of Central Italy. 1-Plio–Pleistocene continental marine deposits and recent alluvial coverings; 2-vulcanites (Pleistocene); 3-syntectonic terrigenous deposits (Cellino formation, lower Pliocene); syntectonic terrigenous deposits (clay–arenaceous formation, upper Tortonian p.p.-upper Messinian); syntectonic terrigenous deposits (Frosinone formation, upper Tortonian p.p); 6-syntectonic terrigenous deposits (Marly–arenaceous formation, Burdigaliano p.p-Langhiano); 7-stratigraphic succession in transition facies (upper Triassic–lower Miocene); 8-stratigraphic succession in carbonate platform facies (upper Triassic–middle Miocene); 9-direct fault; 10-transtensive fault; 11-fault with complex kinematics; 12-transcurrent fault; 13-overrun; 14-perception. Modified after Ref. [4].*

The Pontine Plain extends between the Lepini Mountains and the sea. Beyond this, the promontory of Mount Circeo forms a short (5 km long) limestone chain. **Figure 3** shows the sedimentary terrains surrounding the study area (Pontine Plain). We will focus on the origin of the Pontine Plain in relation to the sedimentology and paleoclimatology, along with a volcanological outline.
