The ancient desert of northeastern Brazil, buried under 200 million years of lava, has revealed a fascinating insight into the past. This discovery not only sheds light on the wind patterns of the supercontinent Gondwana but also offers a unique perspective on climate science. What makes this particularly intriguing is the fact that the desert's preservation allows us to study the wind directions that were calculated for decades without any physical evidence. The key to this discovery lies in the magnetic surveys conducted by geoscientist Rossano Michel and his team, which enabled them to trace the buried dunes underground without any digging. The sand, dating back to the Triassic period, was preserved under the lava cap, halting erosion and preserving the larger form of the desert. This preservation allowed the team to read the layering of the dunes and determine the direction the wind blew. The reconstructed field, spanning over 21,000 square miles, revealed linear dunes that were the result of two prevailing winds from different quarters. The orientation of these dunes provides a heading, with one wind coming from the northeast and the other from the southeast, converging over what is now Brazil. This discovery not only confirms the climate models' predictions of a seasonal monsoon pattern over low-latitude Gondwana but also offers a rare glimpse into a world no one can visit. The lava connection to the volcanic burst that ended the Triassic period and caused a mass extinction further emphasizes the significance of this discovery. In my opinion, this finding is a crucial checkpoint for geologists, providing physical proof of the wind patterns across low-latitude Gondwana 200 million years ago. It also serves as a valuable tool for testing climate models, particularly in understanding how monsoons behave in a high-carbon dioxide atmosphere. The study, published in Communications Earth & Environment, offers a fascinating insight into the past and raises a deeper question about the relationship between climate science and ancient history.
