Estimated depth–pressure–temperature (D–P–T) profile of continental geotherm (orange line, Earth’s mantle up to 3000 km), ocean geotherm (blue line), and connection between the ocean geotherm and continental geotherm (yellow dashed line). These geotherms may vary significantly based on the locations in the Earth’s crust, e.g., below the deep ocean vs. along the pacific ring of fire.