The Serra dos Órgãos ("Organ Range") is a mountain range in the state of
Rio de Janeiro
Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...
,
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. It contains the
Serra dos Órgãos National Park.
Location
The Serra dos Órgãos is the name of the region of the
Serra do Mar in the central part of the state of Rio de Janeiro.
It covers an area of .
The range is an
escarpment on the northern edge of the Guanabara Graben between the cities of
Petrópolis and
Teresópolis.
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.
Topography
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
Rio de Janeiro
Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...
, 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 highway and killed about 20 people.
Geology
The mountains consist of granitic
gneisses 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 last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era an ...
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
File:Grimm 1885, Vista de Teresópolis.jpg, Serra dos Órgãos as seen from Teresópolis, 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 Rio de Janeiro
Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...
File:Parque Nacional da Serra dos Orgaos Rafael Penna Leite (03).jpg, Sunrise
See also
*
Pedra da Gávea
*
Sugarloaf Mountain and Urca Hill Natural Monument
Notes
Sources
*
*
*
{{DEFAULTSORT:Serra dos Orgaos
Orgaos