Pilanesberg Ring Dike Complex

NASA Earth Observatory ^ | 7/22/2015 | NASA

[JimSEA]

While big game animals such as lions, leopards, elephants, rhinos, and water buffaloes draw most visitors to Pilanesberg National Park, the land these animals live on is just as compelling. Pilanesberg is located in one of the world’s largest and best preserved alkaline ring dike complexes—a rare circular feature that emerged from the subterranean plumbing of an ancient volcano. The Operational Land Imager (OLI) on Landsat 8 acquired this image of the park in South Africa on June 19, 2015. Seen from above, the concentric rings of hills and valleys make a near perfect circle, with different rings composed of different types of igneous rock. The entire structure sits about 100 to 500 meters (300 to 1,600 feet) above the surrounding landscape. The highest point—Matlhorwe Peak—rises 1,560 meters (5,118 feet) above sea level. Several streams run through the valleys and faults, though most only flow during the wet season (between October and April). When this image was acquired in June 2015, the streams had run dry. However, man-made dams trap enough water to sustain critical watering holes for the animals. The largest body of water in the park, Mankwe Lake, is visible in the lowlands just east of the center.

[JimSEA]

Also be sure and read the wiki article on this complex where the illustrations give a good detail of the formation and subsequent erosion process.

[Boogieman]

There’s a similar structure on the Peruvian altiplano, and some have hypothesized, if the levels of the nearby lake were higher, it could have been a good candidate to match the descriptions given of “Atlantis”.

[JimSEA]

They do look like bullseyes. To get so many seemingly circular dikes they must have been interesting to watch.