(Table 1) Carbon, hydrocarbons and observations at DSDP Holes 67-497 and 67-498A

Gas hydrates are icelike materials that form when specific conditions of temperature, pressure, and gas composition are simultaneously satisfied. Among the first descriptions of gas hydrates under natural conditions was that of Hammerschmidt (1940), who found them in pipelines used to transport natural gas. Milton (1976) indicates that conditions are suitable for the presence of gas hydrates in areas affected by permafrost and cites studies suggesting that large quantities of gas exist in hydrate form.

天然气水合物（Gas hydrates）是一类类冰状物质，当温度、压力与气体组分同时满足特定条件时即可形成。最早对天然环境中天然气水合物的记载之一出自哈默施密特（Hammerschmidt）1940年的研究，其在输送天然气的管道中发现了此类物质。米尔顿（Milton）于1976年提出，受永久冻土影响的区域具备天然气水合物赋存的适宜条件，并援引相关研究证实，大量天然气以水合物形态储存。