The Lajedo de Pai Mateus is an archaeological site that has a rocky elevation of 1.5 km², with countless other stone blocks. It stands out for its beauty and attracts tourists from all over the country.
No northeastern Brazil, in sectors where outcropping crystalline basement (composed by igneous and/or metamorphic rocksAs pimples e gneisses), the occurrence of forms of saprolitic relief – this is reliefs from rocks profoundly altered by chemical action, depending on water penetration.
These features result from the formation of a mantle of chemical alteration in the subsurface, which is removed by subsequent erosive action, leaving the surface of blocks that have not been completely altered or that are larger than the removal/transport capacity (Twidale, 2002) .
These shapes are found associated with the past occurrence of tropical climates wetter, or, more precisely, to the alternation between wetter and drier climates (Maia and Nascimento, 2018).
Video about Lajedo de Pai Mateus in Paraíba
The more humid climates allow the chemical alteration of the rock in the subsurface (dissolution, rotting of the rock, facilitated by the set of fractures that surface crystalline rocks commonly present), and drier climates imply the removal of altered material, leaving large rocky blocks in the landscape (Twidale, 2002).
The main result of rock alteration is the loss of granular cohesion, thus allowing the evacuation of unconsolidated debris (friable: Vidal Romaní and Temiño, 2004).
Thus, the removal of friable debris resulting from alternations between erosive cycles (humid and dry climates) will originate saprolitic reliefs through the inability of erosion systems to remove the larger granite blocks (Vidal Romaní and Twidale, 1998) (Figure 1 ).
A great example of the evolution of this type of geoform is Lajedo de Pai Mateus. The Lajedo de Pai Mateus is a granite relief located in the city of Headboards, located in the center of the State of Paraíba, 180 km from the capital João Pessoa.
It has an area of approximately 1,5 km² and has about one hundred large rounded rocky blocks that can weigh tons, which stand out amidst the flattened surface that characterizes the cariri paraibano.
Inside, the granite pattern in Lajedo de Pai Mateus presents a great diversity of forms, such as slabs (flat and recessed granite surfaces), boulders (rock fragments of metric dimensions), granite balls e Thu (rocky outcrop that rises abruptly in the middle of a flatter surface) (Figures 2 and 3).
Another type of feature present in Lajedo de Pai Mateus are the basal cavities that form in the large granite blocks, called tafone (tafoni in the plural.). These are concave features that expand upwards from the base of the granite block to consume its interior.
This expansion expands to the point of breaking the side of the block, thus generating access to the inner part of the material. Inside the rocky block, the expansion of the cavity occurs by the progressive desquamation of the internal surfaces accompanied by granular disintegration (Maia and Nascimento, 2018) (Figure 4).
Another smaller feature that occurs in the area are the fluting, which represent shallow vertical grooves produced by chemical erosion (dissolution).
When they occur in profusion, they are called karrens, being characterized by well-marked channels, arranged parallel from the top to the base of the granite block (Maia and Nascimento, 2018). (Figure 5).
In summary, it is assumed that the development of saprolitic granitic morphology, in Lajedo de Pai Mateus and in other locations in the Northeast and around the world, takes place in two steps. At first, it occurs chemical change in the soil base, and in the second one checks the gradual exposure of saprolites through erosion (Roque et al., 2013).
The rock formation would look like this the result of the erosion of the Earth's surface over millions of years, depending on the existence of natural cracks (which allow the penetration of water) and variations between wetter and drier climates, occurring in humid climates to chemical change it is us dry climates, removal of the weathering mantle and exhumation of saprolites. Here is the secret of the origin of these geoforms!
In some blocks of Lajedo de Pai Mateus there are paintings, attributed to Cariri Indians, who have inhabited the region since the early Holocene (10 thousand years).
A toponymy However, the place has another origin: legend has it that Pai Mateus would have been a hermit healer who would have lived in the region around the XNUMXth century, and which would have been much sought after by pilgrims in the region. He owes the historical name of this geomorphological site.
Lajedo de Pai Mateus is located on private property, and access is via a dirt road, from the center of Cabeceiras.
O geosite represents a set of spectacular granite geoforms, whose knowledge is expanding nowadays, and has been the object of increasing visitation. After visiting the area, all that remains is to vibrate with the following greetings: long live geomorphodiversity from Lajedo de Pai Mateus! Live the geomorphic richness from the Brazilian Northeast!
The tourist spot is 25 km away from the center of Headboards, a municipality known throughout the country as “Roliúde Nordestina”, for having been the stage for several cinematographic productions, including the film O Auto da Compadecida, from 2000.
The Lajedo de Pai Mateus, was used as a “Ceremonial Center or Sacred Place” by the prehistoric indigenous peoples who inhabited the region for at least 10.000 years, and that is why many people today find a “mysticism” in its stones.
Its “positive energy” does not go unnoticed by visitors with some sensitivity or “open” to this type of mystical experience.
But regardless of this side, Lajedo is indeed a special region with a unique and beautiful look, in a region marked by the roughness of nature and the sweetness of its natives.
Paraíba and Northeast Tourism Guide – Lajedo de Pai Mateus in Paraíba