A chunk of gas hydrate recovered from shallow depth (~6 m below seafloor) at cold vent Site U1328. Natural gas hydrate is an ice-like crystalline solid formed from a mixture of water and natural gas (e.g., methane) at low-temperature and high-pressure conditions found in marine continental-slope sediments, such as the Cascadia Margin being drilled during Expedition 311, and in onshore Arctic permafrost environments. (IODP) [Photo ID: exp311_115] Back to expedition photos.