denude

Denudation is a geologic term that indicates the process by which the removal of material, through means of erosion and weathering, leads to a reduction of elevation and relief in landforms and landscapes. Exogenic processes, including the action of water, ice, and wind, predominantly involve denudation. Denudation can involve the removal of both solid particles and dissolved material. Both mechanical and chemical weathering occurs in relation to geomorphological landforms. At present the most significant processes leading to denudation include deforestation (including slash-and-burn practises of local peoples), overgrazing and certain forms of intensive farming which lead to large scale erosion. This phenomenon takes place generally by regional uplift by tectonic movement.

Factors affecting Denudation include:

1. Surface geography
2. Properties of Earth material
3. Climate
4. Tectonic setting
5. Activities of man, animals and vegetation

Denudation exposes deep subvolcanic structure on the present surface the area in which volcanic activity occurred in the past. The subvolcanic structure highlighted by differential denudation, such as neck and dyke (geologic terms, volcanic vent), cannot be called as a volcano.

A) Villarica Volcano, Chile, a volcano without effects of erosion and denudation; B) Chachahén Volcano, Mendoza, Argentina, a volcano with strong effect of erosion but no denudation; C) Cardiel Lake, Santa Cruz, Argentina, a volcanic area under strong effect of denudation, exposing subvolcanic rock body. [1]

A) Schmatic illustration of regional denudation for felsic alkaline intrusive rock bodies of the State of Rio de Janeiro, Brazil: Cabo Frio Island and Itaúna Body.

Medical Use

In medicine, denudation refers to the loss of the outside layer, such as the epithelium.

Bibliography

• Hackspacher, P.C., Ribeiro, L.F.B., Ribeiro, M.C.S., Fetter, A.H., Hadler, J.C.N., Tello, C.A.S, Dantas E.L.S. , 2004. Consolidation and Break-up of the South American Platform in Southeastern Brazil: Tectonothermal and Denudation Histories. Gondwana Research, 7-1, 91-101.

• Motoki, A., Petrakis, G.H., Sichel, S.E., Cardoso, C.E., Melo, R.C., Soares, R.S., Motoki, K.F. 2008. Origem dos relevos do Maciço Sienítico do Mendanha, RJ, com base nas análises geomorfológicas e sua relação com a hipótese do Vulcão de Nova Iguaçu. Geociências, Rio Claro, 27-1, 97-113. [2]

• Motoki, A., Sichel, S.E. 2006. Avaliação de aspectos texturais e estruturais de corpos vulcânicos e subvulcânicos e sua relação com o ambiente de cristalização, com base em exemplos do Brasil, Argentina e Chile. Revista Escola de Minas, 59-1, 13-23.[3] doi: 10.1590/S0370-44672006000100003. [4]

• Motoki, A., Sichel, S.E. 2008. Hydraulic fracturing as a possible mechanism of dyke-sill transitions and horizontal discordant intrusions in trachytic tabular bodies of Arraial do Cabo, State of Rio de Janeiro, Brazil. Geofísica Internacional, México. 47-1, 13-25. [5]

• Motoki, A., Sichel, S.E., Savi, D.C., Aires, J.R. 2008. Corpos tabulares de intrusão subhorizontal discordante em torno do sienito da Ilha de Cabo Frio, RJ, e seu mecanismo de posicionamento. Geociências, Rio Claro, 27-2, 207-218. [6]

• Motoki, A., Sichel, S.E., Soares, R.S., Neves, J.L.P., Aires, J.R. 2008. Geological, lithological, and petrographical characteristics of the Itaúna Alkaline Intrusive Complex, São Gonçalo, State of Rio de Janeiro, Brazil, with special attention of its emplace mode. Geociências, Rio Claro, 27-1, 31-42. [7]

• Motoki, A., Soares, R.S., Netto, A.M., Sichel, S.E., Aires, J.R., Lobato, M. 2007. Reavaliação do modelo genético do Vulcão de Nova Iguaçu, RJ: origem eruptiva ou intrusão subvulcânica ? Revista Escola de Minas, 60-4, 583-592. [8] doi: 10.1590/S0370-44672007000400003. [9]

• Motoki, A., Soares, R.S., Netto, A.M., Sichel, S.E., Aires, J.R., Lobato, M. 2007. Forma de ocorrência geológica dos diques de rocha piroclástica no Vale do Rio Dona Eugênia, Parque Municipal de Nova Iguaçu, RJ. Geociências, Rio Claro, 26-1, 67-82. [10]

• Sichel, S.E., Motoki, A., Savi, D.C., Soares, R.S. 2008. Subvolcanic vent-filling welded tuff breccia of the Cabo Frio Island, State of Rio de Janeiro, Brazil. Revista Escola de Minas, 61-4, 423-432. [11] doi: 10.1590/S0370-44672008000400004. [12]

See also

• Desertification
• Overpopulation
• Soil conservation