By Evelyn Hart – Indian Defence Review
In the arid zones of southern Africa, traces of ancient environments are often sealed deep within mineral-rich rock formations. These regions are among the most geologically stable on Earth, and their stone layers preserve evidence of past climates, tectonic events and, occasionally, biological activity. Most features found in such contexts align with established models of geophysical change.
Occasionally, though, a pattern emerges that resists classification. In parts of Namibia, Oman and Saudi Arabia, researchers studying marble and limestone have encountered a set of fine, tube-like structures whose formation cannot be explained by erosion, crystallisation or tectonic stress. Their geometry is precise. Their repetition across disparate regions is consistent. Their origin is unknown.