br.gif (641 bytes)

SIGEP

Geological and Paleontological Sites of Brazil - 029

VILA VELHA

Date: 18/11/1999

Mário Sérgio de Melo 1
Élvio Pinto Bosetti 1, 2
Luiz Carlos Godoy 1, 2
Fernando Pilatti 2

1 Departamento de Geociências. msmelo@uepg.br
2 Núcleo de Estudos em Meio Ambiente - nucleam@uepg.br
Universidade Estadual de Ponta Grossa.
Praça Santos Andrade s/n. CEP 84010-790 - Ponta Grossa-PR, BRAZIL 

© Melo,M.S.; Bosetti,E.P.; Godoy,L.C.; Pilatti,F. 1999. Vila Velha. In: Schobbenhaus,C.; Campos,D.A.; Queiroz,E.T.; Winge,M.; Berbert-Born,M. (Edit.) Sítios Geológicos e Paleontológicos do Brasil. Published 18/11/1999 on Internet at the address http://www.unb.br/ig/sigep/sitio029/sitio029.htm [Actually http://sigep.cprm.gov.br/sitio029/sitio029.htm ]

(The above bibliographic reference of author copy rights is required for any use of this article in any media, being forbidden the use for any commercial purpose)

ABSTRACT

The natural sandstone sculptures of Vila Velha are an impressing example of ruiniform relief, combining the association of erosive processes with pre-existing attributes of the rocks. They are protected by a State Park, which has received about 200,000 visitors/year, what causes some risks for the preservation of such a rich natural environment.
The Vila Velha Sandstone is part of the base of the ltararé Group (Upper Carboniferous to Lower Permian of the Paraná Basin, Southern Brazil). It has a reddish coloration due to the presence of ferriferous cement. Grain size is medium to fine sand, with dispersed argillaceous intraclasts in an incipient planar to cross-bedded stratification.
The natural sculptures have an elevation of 10 to 30 m above surrounding terrain. Their tops show cracks and fracture polygons, while the walls show saliences, hollows, small anastomosing tunnels, alveolar erosive excavations, basal concave surfaces and fractures filled with iron and manganese oxides. Other structures are the sedimentary stratification, vertical and horizontal fractures and pseudo stratification formed by the cementing.
Vila Velha is a natural site with great environmental value. The large outcrop is a singular exposure of the sedimentary attributes and erosive features of the Vila Velha Sandstone. The area is appropriate for environmental study activities, not only because of the ruiniform relief but also the presence of natural preserved ecosystems, with endemic endangered species. Nevertheless, the integrity of this environment is threatened by the massive exploration of the touristic aspect, which has failed to attribute to the park its role of a preservation area.

INTRODUCTION

    Vila Velha (Old Village) is the denomination of an notable group of natural sculptures of ruiniform aspect, developed in Carboniferous sandstones of the Paraná Basin. Situated approximately 80 Km WNW from Curitiba and 20 Km ESE of Ponta Grossa, for a long time Vila Velha has been pointed as a well-known touristic attraction.
   
The singularity of the sculptures enforced the creation of the Vila Velha State Park by the State Law # 1292, of October 12, 1953. The park, 3,122.11 ha large, is much older than the Brazilian environmental legislation and this determined the divergence of aims of the three institutions that are responsible for its administration.
   
The sandstone sculptures have received a variety of names suggested by the imagination of the visiting public: Cyclops city, camel, sphinx, ship's prow, bottle, turtle, wine-glass (the symbol of Vila Velha) and others. The heights range from a few meters to about 30 meters. The erosive forms are distributed on an area of about 10 ha, that is a notable outcrop of periglacial sandstones of non-consensual genesis, where the sculptures reflect the interrelation of various factors: lithology of the sedimentary rock, tectonic and non-tectonic structures, weathering and erosion processes, beyond others.

LOCALIZATION

    Vila Velha is situated in the Municipality of Ponta Grossa, in the Campos Gerais region, State of Paraná, Southern Brazil (Figure 1), on the geographical coordinates 25o14'09''S and 50o00'17''W. The main access is the BR-376, and important road junction that connects the shores, Curitiba (the State capital) and the North of the Paraná State.

fig1.gif (8419 bytes)

Figure 1. Location of Vila Velha Site

HISTORY

    The first white men who saw the Campos Gerais region were the explorers from São Paulo (named bandeirantes paulistas) of the XVI century: Aleixo Garcia in 1526, Pedro Lobo and Francisco Chaves in 1531. It is also described that the Spanish Dom Álvar Nuñez Cabeza de Vaca, Governor of Paraguay in 1541, also came to this region.
   
In the XVII century, expeditions from São Paulo visited the region looking for gold and precious stones, as well to capture Indians. As told by Ferreira & Kersten (1990), this was the time of the first references to Vila Velha, because it was a natural mark for the travelers going south.
   
For the tribal populations, ancient inhabitants of the region, the ruiniform sculptures of Vila Velha were explained by a variety of legends, some of them still told nowadays. The most known is the legend of ITACUERETABA, the "extinct city of stone".
   
In 1876 the First Geological Commission of the Brazilian Empire visited the region of the Campos Gerais. At that time, Luthero Wagoner described the Carboniferous sandstones and Devonian fossils on underlying layers, these later named "Ponta Grossa Formation" (Formação Ponta Grossa) (Lange, 1954).
   
In 1880, the Emperor of Brazil, D. Pedro II, visited the region to know the project of the Russian-German colonization, started in 1878. He stayed in the farmhouse of Domingos Pereira Pinto, the Baron of Guaraúna, in whose lands the strange rock formation was placed.

DESCRIPTION OF THE AREA

    Vila Velha is sculptured on Carboniferous sandstones of the Paraná Basin, that is a vast intracratonic depression of South America, about 1,400,000 km2 in area, extending over Brazil (1,100,000 km2), Argentina (100,000 km2), Paraguay (100,000 km2) and Uruguay (100,000 km2) (Zalán et al., 1991; Milani et al. s.d.) (Figure 2).

The Paraná Basin Sedimentary Filling

    The basin is filled by up to 8,000 m of sedimentary and volcanic rocks, the later to a maximum depth of 1,700 m (Zalán et al., 1991). The older sediments (Rio Ivaí Group) are from the Late Ordovician to Early Silurian (Assine et al., 1994; Milani et al. 1994), and the newer (Bauru and Caiuá Groups) are from the Early Cretaceous (Fernandes & Coimbra, 1994).

fig2.gif (4990 bytes)

Figure 2 . Paraná Basin and the Vila Velha Site. V: Vila Velha; CR: Curitiba; RJ: Rio do Janeiro; BR: Brasília; BA: Buenos Aires.

Geology of Vila Velha

    Vila Velha is placed near the eastern border of the Paraná Basin, about 10 km westward the erosive contact of the Paleozoic sedimentary units over the Proterozoic basement (Figure 3).
   
The rocks of this basement (Açungui Group of the Brazilian Cycle and post-tectonic granitic stocks) form the Primeiro Planalto Paranaense (the First Paraná Plateau), which landscape is leveled between 800 and 900 m above sea level. The Paleozoic sedimentary units of the Paraná Basin form the Segundo Planalto Paranaense (Second Paraná Plateau), which is leveled by a planation surface gently inclined towards the west, with maximum altitudes in the east at about 1,100 m. The limit between the First and Second Paraná Plateau is called the "Devonian" Escarpment, that is locally named Serra de São Luís do Purunã, a mainly erosive cliff up to 200 m high.
   
In this sector of the Paraná Basin occurs the Furnas Formation (basal), that grades to the top to the Ponta Grossa Formation. The Itararé Group lies above these two units, showing clear erosive contacts.
   
Vila Velha is formed by reddish sandstones of the basal portion of the Itararé Group, that also has conglomerates, diamictites, rhythmites, argillites and shales (Maack, 1946a).

fig3.gif (21566 bytes)

Figure 3. Geologic map of Paraná State between Ponta Grossa and Lapa (MINEROPAR, 1989). 1: Proterozoic basement; 2: Furnas Formation (D); 3: Ponta Grossa Formation; 4: Itararé Group (C-P); 5: Rio Bonito Formation (P); diabase dykes (Mesozoic); 7: major faults; 8: Vila Velha; 9: urban areas.

Stratigraphy and Paleoenvironments

    Maack (1946b), named "Vila Velha" the reddish sandstones that form the natural sculptures . Recent researchers are not unanimous about the origin, stratigraphic setting and the age of these sandstones and underlying deposits of the Itararé Group.
   
França et al. (1996)  considered the Vila Velha sandstone as subaqueous lobes formed by dense gravitational flows coming from the base of coastal glaciers. Evidence of hydrodynamic flows indicates shallow water environment, with the shifting of gravitational flows and hydrodynamic processes. The sedimentary filling of the upstream subaqueous channel of the lobes of the Vila Velha Sandstone is represented by the Lapa Sandstone, which shows a linear morphology to the south of Vila Velha. The fossil content of layers included in the Lapa Sandstone permitted to date it to the Westphalian age (Upper Carboniferous). The Lagoa Azul Formation, also with an Westphalian age, is the basal unit of the ltararé Group, and comprises the deposits underlying the Vila Velha and Lapa sandstones (Milani et al., 1994) (Figure 4).

fig4.gif (116027 bytes)

Figure 4. Local Stratigraphyc chart (modified from Milani et al. s.d.)

    Canuto et al. (1997) also recognized a genetic relation among the Lapa Sandstone southward, and the Vila Velha Sandstone northward, this latter at least in part underlying the former. In this alternative model the Lapa Sandstone is seen as the filling (up to 80m thick) of a subglacial tunnel-valley carved on older sedimentary rocks of the Itararé Group, and reaching the Furnas Formation (Devonian) towards the north. The Lapa Sandstone is included in the Itararé Group, but with an uncertain age. Lithosome geometry, low dipping cross-stratification and vertical and horizontal burrows suggest a tidal influenced shallow marine setting for the Vila Velha Sandstone.

Lithology

    The Vila Velha Sandstone shows a few examples of clear sedimentary structures. Incipient bedding and massive-like rocks (Maack, 1946a) and the presence of dispersed argillaceous intraclasts suggest resedimentation by gravitational flows. Ripple marks and low-dipping cross-stratification indicate the influence of hydrodynamic processes (França et al., 1996), maybe in a marine environment influenced by the tides (Canuto et al., 1997).
   
The Vila Velha Sandstone is up to 50 m thick (Maack, 1946a). It overlies conglomeratic sandstones and sandy-clayey rhythmites of the Itararé Group with a concordant contact. The sandstone is a reddish quartzous sedimentary rock with variable sorting. Grain size varies from fine to coarse sand, with basal conglomerate levels. The sandstone minerals are quartz, feldspars (partly weathered to kaolin), muscovite, chlorite and garnet. (Maack, 1946a) also described the role of a thin film of iron and manganese oxides in the shape of many of the Vila Velha natural sculptures. This cementing process combined with differential erosion cause the formation of common mounds with wide tops and concave eroded basis (Maack,1946a) (Figure 5).
   
Iron and manganese oxides cementation is a marked feature of the Vila Velha Sandstone, being the main cause of the colors and shapes that make up the local scenic heritage. The oxides occur as the cement that joins the quartz grains and also as veins a few centimeters thick that fill vertical and horizontal rock fractures. Cementing is clearly a secondary process, and sometimes forms pseudostratification crossing the sedimentary structure.
   
Petrography analysis of samples from different levels of the natural sculptures revealed that the Vila Velha Sandstone is formed by quartz grains, with rare polycrystalline (quartzite) grains and lithic fragments of argillaceous layers, that can generate pseudomatrix (Melo & Coimbra,1996). The minerals described by Maack (1946a), such as feldspars, muscovite, chlorite and garnet should occur only in the layers below the most typical sandstones of Vila Velha.

foto1.jpg (22786 bytes)

Figure 5. Sandstone sculpture with enlarged top showing horizontal non-tectonic fractures.

    The grain size of the sandstones varies from fine to coarse sand, with a predomination of medium sand. Sorting is moderate to poor, and the grains are sub-rounded to rounded and occasionally sub-angular. The framework is closed, and the quartz grains show concave-convex to sutured contacts. Sometimes there is a secondary growth with euhedral development in secondary pores (Melo & Coimbra, 1996).
   
Adding to the ferruginous cementing, the Vila Velha Sandstone also presents a precipitation of manganese oxide, that fills the fractures of the NE-SW and E-W systems. It forms continuous metallic veins a few centimeters thick and unequal cementing of the surrounding sandstones, as botryoidal fringes about 1 cm thick (Melo et al., 1999).

Fracture trends

    The Paraná Basin shows three main trends of tectonic structures (Zalán et al., 1991):

a) NE-SW parallel to the structures of the Proterozoic basement;
b) NW-SE, related to the Gondwana break-up;
c) E-W parallel to oceanic fracture zones.

    These three trends of structures appear in Vila Velha, mainly as long fractures with no or negligible displacement.
    Other two sets of fractures appear in the sandstones
(Melo & Coimbra, 1996):

d) subvertical fractures of non-tectonic origin, exhibiting a concentric setting parallel to the borders of the rocky plateau;
e) subhorizontal structures partially controlled by bedding and formed by relaxing stresses due to load removal.

Forms of the Landscape

    The Vila Velha plateau is a "ruined inselberg" (AB'SÁBER 1977), that is sustained by very eroded sandstones. This contrasts with other nearby sandstone inselbergs, less destroyed by the erosion. This difference indicates that the Vila Velha plateau is in a more advanced erosion stage than the neighbouring inselbergs, giving rise to an exception landscape, marked by "the extravagance of its topographic forms, called ruiniform relief" (Ab' Sáber, op. cit., p.3).
   
The top of the plateau is at 1,012 m above sea level, about the same elevation of the top-surface of the Second Paraná Plateau. The main rivers of the region (Tibagi, Guabiroba) have their riverbeds at about 785 m above sea level.
   
The natural sandstone sculptures are 10 to 30 m high, corresponding to the thickness of the reddish sandstones with ferruginous cementing, that are harder and tend to support plateaux of the landscape. The height of the sculptures can be lower (a few meters), when the erosive processes have isolated them from the rockwalls and lowered their original height.
   
The forms of the sculptures remember towers, sand-clocks, walls, with different ornamentations that reflect the characteristics of the rocks, the fractures and the erosive processes (Figures 5 and 6).
   
The age of the eroded figures is interpreted by geomorphologic correlation. Vila Velha is placed in the Second Paraná Plateau, that is a southward extension of the Depressão Periférica Paulista. These two geomorphologic provinces are levelled by a Neogene planation surface (Soares & Landim, 1976; Melo et al. 1998). Besides, an important phase of lateritization with associated ferriferous cementing is recognised in Southeastern and Southern Brazil, in the limit Pliocene-Pleistocene (QUEIROZ NETO 1974, PENTEADO 1976, MELO et al. 1978), though the erosion of the ruiniform sculptures is post-Neogene.

foto2.jpg (28901 bytes)

Figure 6. Lapiés-like features in the top of the sandstone plateau.

Erosive Processes and Features

    The main erosive agents in Vila Velha are rainwater, organisms (plants, animals and lichens) and the insolation.
   
Rainwater that flows overland causes mechanical erosion, dissolution and reprecipitation. The mechanical erosion with associated dissolution of the cement can form lapiés-like features in the top of the plateau (Figure 6). In the cliffs they can form vertical hollows that evolve to isolated tower-like features, with enlarged tops.
   
As the rainwater drains the rockwalls they also promote the excavation of superficial holes, in a process named "alveolar erosion" (Fortes, 1996). It results from the combined action of mechanical erosion and dissolution of some components (Figure 7). Otherwise, mainly in the northern rockwalls that are more exposed to the sunlight, surface waters reprecipitate a thin coat of iron oxide, which protects the sandstone from erosion. When rich in organic acids from vegetation decomposition, the superficial waters, more corrosive, can dig long and narrow furrows on the surface of the plateau.
   
The rainwater that penetrate the rock massif through the fractures and pores can also give rise to strange excavation features, named "anastomosing tunnels" (Fortes, 1996). Usually such features show apertures of a few centimeters closely controlled by the horizontal fractures. Corrosion cones present in the anastomosing tunnels resemble dissolution and precipitation features (Figure 7), but in this case they must be regarded as a result of mainly mechanical erosion.

foto3.jpg (27117 bytes)

Figure 7. Corrosion cones formed by anastomosed tunnels in horizontal fractures and alveolus due to superficial erosion.

    Organic activity (tree roots, lichens, ferns, orchids, mosses, termites, swallows and "blackbirds") is co-responsible for the processes of degradation of the rocks. Lichens are abundant on the damp walls of the sculptures, which occur mainly where there is no direct sunlight. This contributes to create favorable conditions for the erosive processes, as in the formation of concave surfaces in the base of the sculptures, and in the deepening of fractures, alveolus and tunnels.
   
The sun heating on the surface of the sandstone creates cracks from the phenomenon of constant expansion and contraction. This originates many of the fractures on the plateau and on the walls of its northern face. When the sandstones are uniform (massif-like) the cracks tend to form regular hexagons, which are the shapes that require less energy for rupture (Figure 8). The action of rainwater and organisms then opens and deepens the superficial fractures initiated by insolation.

foto4.jpg (38544 bytes)

Figure 8. Polygonal fractures attributed to insolation associated to linear subvertical fractures.

    Recently, besides the natural factors that promote the erosion of the sandstone, large numbers of tourists have resulted in deep erosion of the paths, while vandals' inscriptions are destroying the rockwalls.
   
There was no evidence found that eolian processes added in the elaboration of the natural sculptures in Vila Velha, but this has been told by some authors (v.g. Soares,1975; Ab'Saber, 1977). The concave bases of some of the forms are attributed to differential erosion of less resistant layers, because of different textures and cementing by iron oxide, what control water percolation and lichens growth.

Figure 10. The Wine-glass, sandstone natural sculpture symbol of Vila Velha. 
(
Photo: Mario Sergio de Melo)

 

PROTECTION PROCEDURES

    Vila Velha is not only a notable geologic/geomorphologic monument, but also an important conservation area for the ecosystems of the Campos Gerais region. The State Park comprises preserved areas of Araucaria (Paraná pine tree) woods, open fields and swampy depressions. There are at least 27 species of endemic vegetation in these ecosystems (Hatschbach & Moreira Filho,1972).
   
These environments are inhabited by a number of animals menaced of extinction (such as the guará wolf - Chrysocyon brachyurus), which belong to the Guarani Fauna Province (Mello Leitão,1947).
   
The following arrangements must be envisaged for improving the preservation and use of the park:

BIBLIOGRAPHIC REFERENCES

Ab´Saber,A.N. 1977. Topografias ruineformes no Brasil. São Paulo, USP - Inst. Geografia, Geomorfologia, n.50, 14p.

Assine,M.L.; Soares,P.C.; Milani,É.J. 1994. Seqüências tectono-sedimentares mesopaleozóicas da Bacia do Paraná, Sul do Brasil. Revista Brasileira de Geociências,24(2):77-89.

Canuto,J.R.; Rocha-Campos,A.C.; Sato,P.E.S. 1997. The Late Paleozoic Lapa Sandstone (Itarare Subgroup): a possible tunnel-valley fill?. Anais da Academia Brasileira de Ciências,69(2):275-276.

Fernandes,L.A.; Coimbra,A.M. 1994. O Grupo Caiuá (Ks): revisão estratigráfica e contexto deposicional. Revista Brasileira de Geociências,24(3):164-176.

Ferreira,D.D.; Kersten,M.S.A. 1990. Mitos e Histórias de Vila Velha. Boletim de Antropologia, Curitiba,3(4):59-74.

Fortes,F.P. 1996. Geologia de Sete Cidades. Teresina, Fundação Cultural Monsenhor Chaves, 144p.

França,A.B.; Winter,W.R.; Assine,M.L. 1996. Arenitos Lapa-Vila Velha: um modelo de trato de sistemas subaquosos canal-lobos sob influência glacial, Grupo Itararé (C-P), Bacia do Paraná. Revista Brasileira de Geociências,26(1):43-56.

Hatschbach,G.; Moreira Filho,H. 1972. Catálogo Florístico do Parque Estadual de Vila Velha (Estado do Paraná-Brasil). Boletim, UFPR, v.28, p.1-54, set.

Lange,F.W. 1954. Paleontologia do Paraná. In.: Paleontologia do Paraná. Curitiba. Comissão de Comemoração do Centenário do Paraná. p. 1-105, dez.

Maack,R. 1946a. Geologia e geografia da região de Vila Velha e consideraçðes sobre a glaciação carbonífera do Brasil. Curitiba, Arquivos do Museu Paranaense, v.5, 305p.

Maack,R. 1946b. Notas preliminares sobre uma nova estratigrafia do Devoniano do Estado do Paraná. In: Congresso Pan-Americano de Engenharia de Minas e Geologia, 2, Rio de Janeiro. Anais... Rio de Janeiro, v.4.

Mello Leitão,C. 1947. Zoogeografia do Brasil. 2ed. São Paulo, Companhia Editora Nacional. Biblioteca Pedagógica Brasileira, série 5, v.77.

Melo,M.S.; Cuchierato,G.; Coimbra,A. 1998. Níveis planálticos da porção centro-leste do Estado de São Paulo e sedimentação associada. Curitiba, Bol. Par. Geoc., v.46 (in press).

Melo,M.S.; Coimbra,A.M. 1996. Ruiniform relief in sandstones – the example of Vila Velha, Carboniferous of the Paraná Basin, Southern Brazil. Barcelona, Acta Geológica Hispanica,31(4): 25-40. (published in 1999).

Melo,M.S.; Coimbra,A.M.; Sayeg,I.J.; Giannini,P.C.F.; Atencio,D. 1999. Fringed cryptomelane/hollandite in the Vila Velha Sandstone telogenesis. São Paulo, Acta Microscopica, v.8(A):35-36.

Milani,É.J.; França,A.B.; Schneider,R.L. 1994. Bacia do Paraná. Boletim. Geoc. PETROBRÁS,8(1):69-82.

Milani,É.J.; Faccini,U.F.; Scherer,C.M.; Araújo,L.M.; Cupertino,J.A. s.d. Sequences and stratigraphic hierarchy of the Paraná Basin (Ordovician to Cretaceous), Southern Brazil. São Paulo, Boletim do IG-USP (in press).

Soares,O. 1975. Geologia. In: Requião, R. (Ed.), Ponta Grossa - História, Tradiçðes, Geologia, Riquezas. Ponta Grossa, Requião e Cia., p.87-92. (Publicação Comemorativa do 152° Aniversário de Ponta Grossa).

Soares,P.C.; Landim,P.M.B. 1976. Depósitos cenozóicos na região Centro Sul do Brasil. Campinas. Notícia Geomorfológica,16(31):17-39.

Zalán,P.V.; Wolff,S.; Conceição,J.C.J.; Marques,A.; Astolfi,M.A.M.; Vieira,I.S.; Appi,V.T.;

Zanotto,O.A. 1991. Bacia do Paraná. In Gabaglia, G.R. and Milani, E.J. (Eds.) Origem e evolução de bacias sedimentares. Rio de Janeiro, PETROBRÁS, p.135-168.