The Serra dos Órgãos ("Organ Range") is a mountain range in the state of

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. It contains the

Serra dos Órgãos National Park Serra dos Órgãos National Park ( pt, Parque Nacional da Serra dos Órgãos: "Organs Range") is a national park in the state of Rio de Janeiro, Brazil. It protects the Serra dos Órgãos mountain range and the water sources in the range. It wa ...

Location

The Serra dos Órgãos is the name of the region of the

Serra do Mar The Serra do Mar (, Portuguese for ''Sea's Ridge'' or ''Sea Ridge'') is a 1,500 km long system of mountain ranges and escarpments in Southeastern Brazil. Geography The Serra do Mar runs parallel to the Atlantic Ocean coast from the state ...

in the central part of the state of Rio de Janeiro. It covers an area of . The range is an

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''esca ...

on the northern edge of the Guanabara Graben between the cities of

Petrópolis Petrópolis (; ), also known as The Imperial City, is a municipality in the Southeast Region of Brazil. It is located in the state of Rio de Janeiro, northeast of the city of Rio de Janeiro. According to the 2010 National Brazilian Census, Petr ...

and

Teresópolis Teresópolis (, , , ) is a Brazilian municipality located in the state of Rio de Janeiro, in a mountainous region known as ''Região Serrana''. The Serra dos Órgãos National Park lies partly within the city limits. The city is known as the hom ...

. The name comes from perceived resemblance of the vertical rock formations created by erosion to the tubes of organs used in Portuguese churches at the time.

Topology

Along the escarpment the altitude ranges from near sea level in the coastal plain to above sea level further inland. The average elevation is above sea level. The Dedo de Deus (God's Finger) and Escalavrado, at and and the nearby peaks with steep rock walls are dramatic features that can be seen on a clear day from

, which is distant. The highest point is Pedra do Sino (Bell Rock) at . A north west fracture is exposed at the plateau's rock surfaces, which defines the direction of the ridges and valleys along the escarpment. One of these ridges contains several granite peaks including God's Finger. North east vertical fractures, spaced regularly about every , cut the north west structures at right angles. Erosion along these fractures has isolated the massive rock blocks. The valleys have well-preserved deposits of debris that has fallen from the rock walls. In November 1981 a period of intense rain triggered hundreds of shallow landslides and flows of debris that blocked the

BR-116 BR-116 is a federal route of highways of Brazil and the longest highway in the country, with of extension. The road connect Fortaleza, Ceará, one of the largest Northeast Brazil metropolises, to the southern city of Jaguarão, Rio Grande do S ...

highway and killed about 20 people.

Geology

The mountains consist of granitic

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures a ...

es of the Neoproterozoic era. The region is structurally complex with considerable faulting combined with erosion. The ridge containing the God's Finger and other towers is unusual in being sustained by a thick dike of Cambrian granite that is more resistant to erosion than the surrounding

Neoproterozoic The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is prec ...

orthogneisses. Formation of the rocks may have occurred around 620 million years ago. File:Rugendas - Serra dos Orgaos.jpg, Serra dos Orgãos during the 1820s. Painting by

Johann Moritz Rugendas Johann Moritz Rugendas (29 March 1802 – 29 May 1858) was a German painter, famous in the first half of the 19th century for his works depicting landscapes and ethnographic subjects in several countries in the Americas. Rugendas is considered " ...

File:Grimm 1885, Vista de Teresópolis.jpg, Serra dos Órgãos as seen from

, 1885. Oil on canvas by Georg Grimm File:Serra dos Órgãos 02.jpg, Peaks (from left to right): ''Escalavrado'', ''Dedo de Nossa Senhora'', ''Dedo de Deus'', ''Cabeça de Peixe'' and ''Santo Antônio''. File:Zona Norte.JPG, Serra dos Órgãos, in the background, as seen from the city of

Notes

Sources

* * * {{DEFAULTSORT:Serra dos Orgaos Orgaos

Location

Topology

Geology

See also

Notes

Sources