article_snippet.sent: The gas forms through a process called serpentinisation.
article_snippet.sent: Serpentinisation occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor .
article_snippet.sent: all the world's oil, coal and gas put together believe the gas forms through a process called serpentinisation. '
article_snippet.sent: Serpentinisation occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor,' said Johnson. '
article_snippet.sent: These only form in slow to ultraslow spreading seafloor crust.
article_snippet.sent: The optimal temperature range for serpentinisation of ocean crust is 200 – 350 degrees Celsius.'
article_snippet.sent: Methane produced by serpentinisation can escape through cracks and faults, and end up at the ocean floor, causing a concern for future global warming.
article_snippet.sent: But if the pressure is high enough, and the subsea floor temperature is cold enough, the gas gets trapped in a hydrate structure below the sea floor.'
article_snippet.sent: But Samples of the gas hydrates need to be drilled, as Samples of the gas hydrates are 140 metres under the ocean floor .