El Penon de Guatape
El Penon de Guatape
Not far from Guatape, Columbia stands this massive structure carved painstakingly from igneous intrusions dating from the late Cretaceous 70 million years ago. Time enough under tropical conditions to rot and decay even the toughest granite.
The Antioquia Batholith.
The Antioquia Batholith, named after a region in Columbia forms a round structure in the middle of the relief map. It covers an area of about 7,800 square kilometers. Batholiths/Plutons occur when a large volume of magma intrudes and cools deep in the Earth’s crust.
The Antioquia Batholith consists of late Cretaceous Gabbro-Granite intrusions weathered at depth to form saprolite. This special type of weathering at depth only occurs on landmasses between latitudes 35°N and 35°S. Seventy million years under hot steamy tropical conditions turns even the toughest granite to mush
Deep weathering, Saprolite formation
Special conditions are needed for deep weathering and saprolite formation.
A flat topography that allows leaching without much erosion.
Long periods of tectonic stability and a humid or tropical climate. Weathering, breaking down the granite to saprolite with very little erosion. In some locations this saprolite reaches thicknesses of about 200 metres
70 million years of deep weathering has left the region under a 40 meter mantle of red coloured saprolite deposits. In some places saprolite deposits can be 200 meters thick…
Weathering of igneous intrusions is slow. Some parts of the Batholith are jointed, water penetrates and they weather faster.
Inselbergs, tall columns of poorly jointed and weathering resistant rock break through the surface.
There are 659 steps on the way up to the top where apart from admiring the view you can also buy beer. Constructing the staircase was a remarkable feat of engineering and climbing skills but they forgot an elevator to get the beer up.
“Dos Cervesas por favor Amigo.” confidently ordering a couple of beers without using google translate.
Then the awefull realisation, “Ay mierdo, Olvidé traer mi billetera.”
