Aberystwyth, Wales – Sand dunes are iconic features of arid landscapes, shaping some of the most breathtaking scenery on Earth. Among these dunes, star dunes stand out for their towering height and unique star-like formation. Found in sand seas across Africa, Arabia, China, and North America, star dunes are characterized by a central pyramid structure with multiple arms spreading out, creating a star shape when viewed from above.
Despite being common in modern deserts and even appearing on other celestial bodies like Mars and Saturn’s moon Titan, star dunes have been challenging to detect in the geological record. However, recent research led by Professor Geoff Duller from Aberystwyth University, in collaboration with researchers from Birkbeck and University College London (UCL), sheds light on the internal structure and formation speed of a star dune in Morocco.
The study focused on a star dune named Lala Lallia in the Erg Chebbi region of southeastern Morocco. This particular dune rises about 328 feet and stretches approximately 2,297 feet across its base. Through ground-penetrating radar scans, scientists discovered that the dune remained largely inactive for around 8,000 years before rapidly accumulating sand over the past thousand years, shifting westward at a rate of about 1.6 feet per year.
By using optically stimulated luminescence (OSL) dating, researchers were able to determine when minerals in the sand were last exposed to sunlight, pinpointing the time when the dune began forming after the African Humid Period. These findings challenge previous assumptions about the formation rate of large star dunes and offer valuable insights into the geological history of these unique landforms.
The discovery of the Lala Lallia star dune in Morocco provides a better understanding of why star dunes are often absent in ancient rock layers. The study’s results offer a new model for identifying similar formations preserved deep underground, providing geologists with a clearer guide for recognizing these features in the geological record.
Star dunes are crucial to studying past environments and understanding the climatic conditions that shaped Earth’s surface thousands of years ago. By unraveling the mysteries of these giant dunes, scientists gain valuable insights into ancient wind patterns, periods of environmental stability or dryness, and the potential implications for managing water resources in desert regions today.
Ultimately, the research conducted on star dunes in Morocco highlights the importance of studying these geological formations for unraveling the complexities of Earth’s history and better preparing for the future challenges of climate change and desertification.