Dry River Geomonument

Category: Nature > Reserva natural

District: Lisboa > Lisboa > Lisboa > Ajuda

Location

Located in the Ajuda parish, in Lisbon, the Rio Seco Geomonument is a rocky outcrop integrated into the urban environment. This site offers a unique opportunity to observe a part of the city's geological history, presenting itself as a natural element directly accessible within the surrounding fabric of Ajuda.

The geomonument consists of a natural exposure of rocks that is discreetly revealed in the landscape, allowing visitors an uncommon perspective on Lisbon's subsoil.

A Journey Through Geological Time

The Rio Seco Geomonument is a direct testament to a distant period of Earth's history. Approximately 97 million years ago, in the Late Cretaceous, the area where Lisbon is now located was covered by a shallow, clear, and warm sea. These conditions were ideal for the proliferation of marine organisms that formed skeletons and shells of a calcareous nature.

Among these organisms, rudists, colonial mollusks that formed reef banks, stand out. The limestone layers visible in this geomonument are the direct result of the accumulation and fossilization of these beings, offering a unique opportunity to understand the marine landscape that existed in this location millions of years ago.

The Legacy of Lisbon's Limestone

The limestone present in this geomonument, known in some varieties as lioz, has been a material of great importance for the construction of the city of Lisbon over the centuries. Since antiquity, this stone has been the basis for the masonry, stonework, and statuary that have shaped the architectural identity of the Portuguese capital.

At the Rio Seco Geomonument site itself, this limestone was not only extracted for direct use in construction but also for the manufacture of lime. Thus, visiting this geomonument allows the visitor a tangible understanding of the origin of a material that not only supports many of Lisbon's historic buildings but also reveals its deep connection with the region's geological past.

License: https://creativecommons.org/licenses/by-sa/4.0/deed.pt