In a groundbreaking study, scientists have unraveled the mysteries surrounding the formation and age of star dunes, massive sand mounds with distinctive pyramid shapes found in sandy deserts around the world. The investigation focused on Erg Chebbi, a region in the Sahara Desert in Morocco, and revealed surprising insights into the age and growth of one particular star dune, shedding light on the potential presence of ancient star dunes in the geological record.

Using radar scans and sand grain analysis, researchers mapped the internal structure of the star dune in Erg Chebbi. Their findings revealed that the base of the dune formed approximately 13,000 years ago, while a period of minimal growth followed for around 8,000 years. Unexpectedly, the majority of the dune's growth occurred over the past 1,000 years, defying previous assumptions about the slow accumulation of sand in star dunes.

The rapid growth observed in Erg Chebbi's star dune surprised scientists. "I found their results very interesting because, like most people, I had not suspected that star dunes could accumulate so quickly," remarked Andrew Goudie, a geography professor at the University of Oxford. Previous research on the global distribution of star dunes supported this notion.

Additionally, the study revealed that the star dune was actively moving, advancing at a rate of approximately half a meter per year. This finding highlights the importance of understanding the speed and movement of star dunes for infrastructure planning in desert regions, where their migration could impact the construction of roads and pipelines.

The research team led by Charles Bristow, a sedimentology professor at the University of London, meticulously mapped the star dune known as Lala Lallia using ground-penetrating radar, which provided high-resolution images of the sediment layers beneath the dune's surface. Sand samples extracted from different depths within the dune were analyzed using optically stimulated luminescence dating, a technique that measures the age of sand grains based on the accumulated environmental radiation.

Surprisingly, the study also addressed a long-standing geological mystery: the scarcity of ancient evidence of star dunes in the geological record. While desert environments tend to preserve dunes in sandstone layers, ancient star dunes have been exceptionally rare, with only one known example in Scotland dating back to the Permian-Triassic period. The researchers propose that the preserved structures of eroded star dunes may have been misidentified as remnants of other types of dunes, explaining their absence in the geological record.

The newfound understanding of star dunes has been made possible by advancements in technology, including remote sensing tools like Google Earth, which have allowed scientists to identify and study these features on a global scale. Researchers now have a broader awareness of the prevalence and significance of star dunes in shaping sandy desert landscapes.

The revelations from this study not only shed light on the formation, growth, and migration of star dunes but also highlight the potential existence of ancient star dunes that have been hiding in plain sight. Further research in diverse desert environments may uncover more evidence of these enigmatic natural wonders, revolutionizing our understanding of their role in Earth's geological history.