Photographer's Note

If you like rocks and rock formations, Damaraland is a fascinating area of Namibia to visit. The high relief and minimal soil cover result in exposed rocks and a harsh but beautiful landscape.

Pictured here you can see the rust coloured dolerites which line a dry river bed.

The dolerite sill formed by magmatic events which affected large parts of Damaraland about 125 million years ago. Although dolerites occur in many parts of the country, this outcrop shows something special to the visitor. The molten magma penetrated into the surrounding rock parallel to the rock layers, thus the dolerite is solidified into a group of homogeneously orientated columns which results in polygonal cross-sections, the ‘organ pipes’.
The geometrical shape of the polygon (polygonal system)) is a widely distributed fundamental principle. Examples not only occur in a geological context, but are also known in biology (just think of honeycombs). In geology, all intrusive types of rock, like dolerite, tend to form polygonal sections. Basic laws of physics can explain this: any freely deformable body tends to form a sphere, because a sphere is the body with the largest volume and the smallest possible surrounding surface area. Bodies that cannot form freely, like confined basalt rock, form polygons. This is because hexagons or polygons are the geometrical shapes that are most similar to a sphere. Furthermore, polygon bodies, with their square forms can be connected together without any gaps in-between, a property, which a sphere obviously cannot fulfill. Therefore, polygons are the geometric forms in nature, which allow uninterrupted connection of different parts by creating the highest possible volume in the smallest surrounding surface area.
The doleritic magma, which solidified at the Valley of the Organ Pipes, cooled form the outside to the interior of the molten rock mass. The rock being confined could not move in any particular direction. By this cooling-off, the rock contracted. This resulted in thin cooling-off fissures, which were orientated in polygonal sections. Thus basalt columns were formed, which you can study on a walk through the small valley, and the ‘Valley of the Organ Pipes’ gives you a fascinating example of the strict laws of nature.

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Additional Photos by Rosemary Walden (SnapRJW) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2818 W: 85 N: 6957] (31629)
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