Scientists have determined the age of one of Earth’s most majestic natural formations, i.e., the star dune. Towering hundreds of meters in height, these pyramid-shaped dunes have long fascinated researchers due to their unique structure and occurrence on multiple continents, including Africa, Asia, and North America. Notably, star dunes can even be found on Mars. The lack of knowledge about their age has been a longstanding mystery, but recent breakthroughs have allowed scientists to date one of these remarkable formations.
Discovery of Lala Lallia:
Lala Lallia, a star dune in the Erg Chebbi sand sea in southeast Morocco, has been identified as a critical player in unraveling the mystery of star dune formation. The dune, standing at an impressive 100 meters in height and 700 meters wide with radiating arms, has been revealed to be around 13,000 years old. This discovery marks a significant leap in understanding these colossal structures, shedding light on the forces that shaped them and the era’s climate.
Formation and Growth:
Star dunes are crafted by opposing winds that change direction over time. The study of Lala Lallia’s age has provided valuable insights into the historical patterns of these winds, allowing scientists to paint a clearer picture of the climatic conditions during the dune’s formation. After an initial growth phase, Lala Lallia remained dormant for approximately 8,000 years before rapidly expanding in recent millennia. This newfound knowledge challenges previous assumptions about the stability of these massive dunes over time.
Uncovering the Age with Luminescence Dating:
The groundbreaking research, led by Prof Geoff Duller at the University of Aberystwyth and Prof Charles Bristow at Birkbeck University, utilized a technique called luminescence dating to determine the age of Lala Lallia. This method involves analyzing sand samples from the dune in conditions resembling a dimly lit photography workshop. The mineral grains in the sand act as “rechargeable batteries,” storing energy derived from natural radioactivity in the environment. By measuring the last exposure of these grains to daylight, scientists could accurately calculate the age of the star dune.
Implications and Future Research:
The revelation of Lala Lallia’s age challenges previous assumptions about the permanence of these colossal sand formations. The study’s findings suggest that star dunes can form relatively quickly and have the capacity for dynamic growth after dormancy periods. Prof Duller notes that these findings may surprise many, as the enormous dune is currently shifting across the desert at an impressive rate of approximately 50 cm per year.
The exposure of Lala Lallia’s age represents a significant milestone in understanding Earth’s geological history and the forces shaping its landscapes. The application of luminescence dating has provided a valuable tool for researchers seeking to unravel the mysteries of these enigmatic star dunes. As we continue to explore Earth’s diverse terrains, the age-old sands of Lala Lallia stand as a testament to the dynamic and ever-changing nature of our planet’s landscapes.