Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
ExxonMobil Upstream Research Company, Houston, TX, USA.
Science. 2014 Jun 27;344(6191):1500-3. doi: 10.1126/science.1254509.
Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.
甲烷是一种重要的温室气体和能源资源，主要由低温环境下的产甲烷菌和高温环境下的有机分子分解产生。然而，自然界中甲烷形成的温度往往难以确定。我们使用“同位素分馏”技术测量了热成因甲烷和生物成因甲烷的形成温度。热成因气体的形成温度在 157°C 至 221°C 之间，处于名义气体窗内，而生物成因气体的形成温度与其相对较低的形成环境温度一致（<50°C）。在气体已经迁移且其他气体生成温度的示踪剂给出模棱两可结果的系统中，甲烷同位素分馏温度可以区分不同的气体形成模型，并对其进行独立测试。
