Folding, Weathering & Erosion

Chapada Diamantina contains breathtaking views shaped from folding. The national park is also the outcome of ancient weathering and erosion, resulting in beautiful features.

A Chapada Diamantina view made possible through folding processes

Folding is always the result of compression stresses and once a fold is eroded there are unique landforms created. Chapada Diamantina expresses an anticline fold within the rock groups of the Paraguaçu region. Once the anticline fold eroded over time, an anticlinal valley was produced.

Chapada Diamantina's Anticlinal Valley, Pai Inacio, is the result of an anticline fold erosion

The Paraguaçu region within Chapada Diamantina consists of sandstones, siltstones, and argillites. These rocks are much softer, allowing them to be vulnerable to weathering and folding. The folds in the Paraguaçu region allow water to easily enter the rock’s structure, which results in the erosion of these rocks.

Rock types (sandstones, siltstones, and argillites) within Chapada Diamantina's Paraguacu region

Ancient rivers and oceanic currents are responsible for the weathering as well as erosion of the rocks at Chapada Diamantina. Dating the rocks shows that Chapada Diamantina ages back to Pangaea. The national park is an ancient site, which has been broken down and shaped through weathering and erosion. Weathering refers to the breaking down of rock whereas erosion indicates the transport of weathered material.

Chapada Diamantina's, Canyon do Buracao, depicts the weathering and erosion that has crafted a majestic scenery

The rocks in Chapada Diamantina’s Paraguaçu region are rich with minerals, allowing a chemical decay process to occur. The chemical decay process is understood as the chemical alteration or decomposition of rocks and minerals. The sandstones, siltstones, and argillites are chemically decayed through dissolution as well as chelation and biological organic acids. Through dissolution minerals in the rocks are completely dissolved by water. Epilithic, or rock surface, organisms such as mosses alter and decompose the mineral rich rocks at Chapada Diamantina through chelation.

Fumacinha Fall surrounded by weathered rock created through dissolution and chelation processes, depicted by grooves in the rock walls and mosses atop rock surface

Overall, Chapada Diamantina’s Paraguaçu region was made possible by folds created from compression stresses as well as through weathering and erosion. The results of such processes are anticlinal valleys like Pai Inácio and beautiful scenery such as Fumacinha Fall and Buracao Fall.

Buracao Fall portrays evidence for weathering and erosion of mineral rich rock such as sandstone

References

http://gosouthamerica.about.com/od/braregnortheast/p/ChapadaDiamant.htm

http://www.atlasofwonders.com/2011/11/chapada-diamantina.html

http://www.biosferabrasil.com/meu_destino.php?cod_destino=4&idioma=i