Earth’s Second-Oldest Orbicular Rock Found in Madhya Pradesh

Key facts

• The Pichhore orbicular granite, located near Kutawali in Shivpuri district, Madhya Pradesh, has been confirmed as the second-oldest formation of its kind on Earth at approximately 2.56 billion years.
• The rock contains orbicules—spherical structures up to 30 cm in diameter—formed by a thermal pulse and rapid undercooling in a magma chamber during the Neoarchean era.
• An international consortium including Banaras Hindu University (BHU), University of Campinas (UNICAMP), Indian Institute of Technology (IIT) Kanpur, Japan Advanced Institute of Science and Technology (JAIST), Indian Institute of Science Education and Research (IISER) Berhampur, and AllGeo Solutions Pvt. Ltd. conducted the study.
• Researchers used U-Pb zircon dating and Neodymium isotopic analysis to determine the age and origin, finding inherited zircon crystals as old as 3.5 billion years that indicate crustal recycling.
• The site was previously designated a National Geoheritage Site by the Geological Survey of India (GSI), but scientists urge stricter protection due to threats from agricultural expansion and quarrying.
• The findings provide insights into crustal stability, early plate tectonics, and serve as a global benchmark for comparing Neoarchean geological processes.