In the Colombian department of Antioquia between the towns of Guatapé and El Peñol there is an enormous monolith which is called the El Peñón de Guata
In the Colombian department of Antioquia between the towns of Guatapé and El Peñol there is an enormous monolith which is called the El Peñón de Guatapé. It is also called the Rock of Guatapé or the Rock of Peñol – depending on which town the speaker is from. The monolith stands out in the landscape surrounded mostly be grassy plains and lakes, which explains why the locals have long viewed this feature as something special and mysterious.
The clearest example of this is that the stone was worshiped by the Tahamies who lived in the area before the arrival of the Spaniards. It is uncertain what the rock is, or how it formed, but it is very smooth and most likely part of a granitic pluton that was uplifted during the formation of the Cordillera Occidental mountain range in Colombia.
View of El Peñol in Guatape, Colombia. ( Bianca /Adobe Stock)
Features of the Rock of Guatapé in Colombian Geological History
The rock is 656 feet or 200 meters tall and is mainly composed of quartz, feldspar, and mica minerals. It is described as weighing about 10 million tons, though this may not be an exact estimation. The rock itself is about 70 million years old. The region surrounding the rock has a varied geological history. During the early Mesozoic Era , about 251 to 145 million years ago, most of Colombia was underwater – as evidenced by marine sedimentary deposits that date to that time.
By the Cretaceous Period , about 145 million years ago to 66 million years ago, the Colombian Cordilleras had begun to form. This created numerous volcanoes and caused the surface to be uplifted as the Nazca and South American Plate continued to collide. This caused the mountain building event which resulted in the Cordillera Occidental, the mountain range closest to the town of Guatapé.
The amazing rock of Guatape (Piedra Del Penol) and Lake in Guatape landscape view, Colombia. ( photomaticstudio /Adobe Stock)
As the Cordillera Occidental continued to form, ancient magma chambers deep within the crust, which had long since cooled and hardened into granitoid plutons, began to be carried to the surface. Over time, weathering and erosion exposed them to the air. This created a large belt of granitoid rocks along the edges of the Cordillera Occidental. The uplifting and subsequent exhumation of plutons tends to result in large masses of rock across the landscape which are smooth and striking enough to appear almost artificial.
An example of this phenomenon might be the Half Dome in Yosemite, which is an enormous mass of granite which has been exposed at the surface by ages of erosion and cut by glaciers – giving it an appearance which reminded the Yosemite natives of a basket. In light of this, the rock of Guatapé is most likely part of a larger pluton which has been exposed at the surface. There is some speculation that it may have been created by an ancient civilization, but for now there isn’t any real evidence for this. Despite the unusual placement of the rock and its smoothness, the monolith appears to be natural.
The Impact of the Rock of Guatapé on Local Colombian Culture
The Rock of Guatapé has had a significant impact on the surrounding culture. It was apparently worshiped by the Tahamies, a South American agricultural society ruled by hereditary chieftains, and the original inhabitants of the land. It is not known what the Tahamies believed about the rock, but they appear to have been impressed by it. They likely believed it to be of divine or otherwise otherworldly origin since there is nothing like the Rock of Guatapé in the immediate region.
In 1954, the rock was scaled by two friends, encouraged by a local priest, who made it to the top of the rock by using wooden planks inserted into cracks in a large fissure in the stone. They were the first adventurers known to climb the rock in historical times. At a later date, a series of stairs were built into a major fissure in the rock making the journey easier.
Rock of Guatapé (Piedra de Peñol) near to Medellin in Colombia. ( sevenkingdom /Adobe Stock)
Rock of Guatapé or Piedra de Peñol?
Today, there is a visitor center at the top and it is a popular tourist destination . There is also a rivalry between the two nearby towns over ownership of the rock. The rock marks the boundary between the two cities of Guatapé and El Peñol.
The town of El Peñol claims it as belonging to El Peñol, so it is also referred to now and then as the Rock of Peñol. At one point, the people of Guatapé decided to settle the issue by painting, in giant letters, the name of their town onto the rock. News of this quickly spread to El Peñol, causing a mob to come from the neighboring town and put a stop to it. This resulted in only the “G” and part of the “U” being completed.
The ‘G’ and part of the ‘U’ on the giant rock in Guatapé, Colombia. (Bubenik /Adobe Stock)
The rock continues to be of interest to tourists and a subject of geo-social mystique. Not much scientific work appears to have been done on it, probably because geologically speaking it is not very interesting. It is, after all, just a giant mass of granite, features that are found all over the planet. However, the rock is also culturally significant and shows how geology can affect and excite the human imagination just as much as astronomical or zoological phenomena.
Top Image: The Rock of Guatapé (El Peñon de Guatapé), Colombia. (Boris G/ CC BY NC SA 2.0 )
By Caleb Strom