Reference

Differentiating between biogenic and abiogenic methane involves several methods, primarily based on geochemical indicators. These include:

1. Stable Isotope Analysis: Carbon and hydrogen stable isotope ratios are used to distinguish between methane sources. Biogenic methane typically has a more negative δ^13C and δD values compared to thermogenic methane. Abiogenic methane often exhibits even lighter isotopic compositions. Redefining the isotopic boundaries of biogenic methane

2. Carbon Isotope Ratios: The carbon isotope ratio (^13C/^12C) can help differentiate between the two. Biogenic methane has a δ^13C value typically between -20‰ and -60‰, while abiogenic methane can have even lighter values. Unravelling abiogenic and biogenic sources of methane in the Earth's deep subsurface

3. Hydrogen Isotope Ratios: The hydrogen isotope ratio (D/H) is also used, with biogenic methane having δD values between -100‰ and -250‰, and abiogenic methane having even lighter values. Unravelling abiogenic and biogenic sources of methane in the Earth's deep subsurface

4. Geochemical and Geological Tools: These tools are used to evaluate the origin and distribution of methane, often in conjunction with isotopic analysis. Distinguishing Abiogenic Versus Biogenic Sources of Methane and Implications for Mars Exploration

5. Bulk Isotopic Composition: Measurements of methane's bulk isotopic composition, denoted as δ^13C and δD, can help identify different sources and sinks of CH4. Unravelling abiogenic and biogenic sources of methane in the Earth's deep subsurface

6. Methane to Ethane Ratio: Abiogenic methane often has a higher methane to ethane ratio compared to biogenic methane.

7. Helium Isotope Ratios: The presence of helium isotopes can also indicate abiogenic methane, as ^3He is often associated with mantle-derived gases.

These methods are crucial for understanding methane sources, which has implications for climate change, energy resources, and even the potential for life on other planets.