CERRO WITNESS: CHARACTERISTICS AND EXAMPLES - GEOGRAPHY - 2024

A witness hill or hillock are those reliefs that are isolated in a flat territory. Consequently, it consists of a residual relief that has been sculpted by the wear produced as a result of erosion.

This natural phenomenon works as a kind of testimony both to the evolution and to the retreat of a platform or a slope. It is a hill product of a remainder from an old platform; This phenomenon appears in a relief where you can find layers of soft and hard rocks located horizontally.

Pilot Mountain, located in the United States, is an example of a witness hill. Source: pixabay.com

This means that the landscape of this type of hill has horizontal lines that distinguish it from other reliefs. In addition, as the erosion process increases - generally produced by rivers - hills are formed. This can cause a territory to be filled with several witness hills that have a flat summit.

In other words, these reliefs are known as witness hills since they have remained as witnesses of the platform that existed in that territory millions of years ago, and that was modified over time through erosion produced by water.

A witness hill can also be defined as a kind of hill whose top is flat surrounded by a remarkable cliff, which ends up extending into a wide plain. Sometimes the term can be used to refer to a relief that consists of an elevation greater than that of a hill, but is not so high as to call it a mountain.

For example, in some regions of the United States you can see hills that consist of a flat top and horizontal lines; However, it cannot be said that these reliefs are witness hills because they are usually smaller. Of course, both formations are the product of erosion.

characteristics

The witness hills can be classified as "island mountains" and are characterized by having been preserved from erosion, which has dismantled the rest of the surrounding materials. The island mountains have remained protected thanks to a more resistant lithology (hard rocks) that appears at the top.

These hills are also characterized by being very useful for geology studies, since they are the only relics that belonged to geological formations that previously covered a region and were displaced by erosive agents. This "erosion-sedimentation" elimination process is typical of external geodynamics.

Likewise, the witness hills are characterized by having been surrounded by water, which is why they are usually located near rivers that lead to the ocean. According to some scholars, these reliefs must have been formed between the Lower Miocene and Middle Lower ages, taking into account a geomorphological chronology.

Some connoisseurs have established that, generally, these reliefs have a location that has a fin-paleogene age formation, having a strong arcosic character.

This formation is not usually covered with red sediments, since these occur in the Miocene sedimentation. If these reddish vestiges are found, it would only be for the first three or four meters of the hill.

Difference with páramo

The witness hills differ from the moors or tables mainly due to their size dimensions, since the tables tend to extend throughout the territory and are much higher. In other words, their main difference is that the witness hills or "island mountains" are solitary and much smaller.

In addition, the páramo encompasses an entire ecosystem of a montane and intertropical character, with a predominance of shrub vegetation, which classifies it in biogeographic terms as a prairie due to its type of vegetation.

On the other hand, the witness hills are isolated and, although they also have shrubs and bushes, their vegetation is much smaller.

Examples

The witness hills can be found mainly in countries such as Spain, the United States, Venezuela and other regions of Latin America. Here are some examples:

Pilot Mountain, located in North Carolina

This particular hill is located in the United States and is one of the most emblematic natural features of the state of North Carolina.

Its height consists of about 2421 feet above sea level and it is a surviving mount of the ancient Sauratown Mountains. It was designated as a World Heritage Site in 1974.

Cerro La teta, located on the La Guajira peninsula

This witness hill is located in the northwestern part of the South American continent, in the north of Colombia. It is part of the Guajiro massif and has a height of about 370 meters. Its soil is mainly composed of feldspar.

According to geologists, this hill was part of the El Calabozo platform, which was located in western Venezuela; this was shallow.

The witness hill of Castrojeriz, located in Spain

This mountain is not interesting for its notion of witness, but it generates interest for its stratigraphic character; Due to its peculiar shape, it is part of the geological singularities of this country.

This hill was formed during the sediments that emerged in the Duero Basin, so it is estimated that it appeared between the Tertiary and Neogene periods. In turn, it was formed during three main cycles or phases, elapsed in the Middle Miocene and the Upper Miocene.

Witness hills in the Guayana region, located in Venezuela

In the Guayana region, located in Venezuela, you can find several witness hills that were formed during the progressive disappearance of the rocks that covered the Guiana shield. Consequently, the landscape of this area is characterized by plateaus, tepuis and other series of hills and hills.

One of the best known examples of this country is the plateau located in the Gran Sabana, which has an area of ​​about 18,000 km ². In this region you can not only find witness hills, but also plateaus and tepuis.

Taking into account some scientific sources, it can be established that this phenomenon originated in the Archaic era; that is, about 1800 or 1600 million years ago.

References

1. Arismendi, A. (sf) "Guyana, a natural landscape: relief of ancient heights and plains". Retrieved on April 1, 2019 from Fundación Empresas Polar: fundacionempresaspolar.org
2. Dolores, E. (sf) "The Spanish geographical space." Retrieved on April 1, 2019 from Geography of Spain: geoirm.wordpress.com
3. Molina, E. (1991) "Alterations and paleoalterations in the morphology of the western peninsula". Retrieved on April 2, 2019 from Google books: books.google.co.cl
4. Ridruejo, C. (sf) "Geological heritage of the Camino de Santiago". Retrieved on April 2, 2019 from Google books: books.google.co.cl
5. "Cerro witness". Retrieved on April 2, 2019 from Wikipedia: Wikipedia.org