Puzzling Topography on Madagascar (IMAGE) Washington University in St. Louis Caption Field of volcanoes on the island of Madagascar puzzles geologists. What is the source of the heat that melts the rock? Credit Rando Trek VTT Usage Restrictions Please credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.