Reference

The main counterarguments against the abiogenic origin of petroleum are:

1. Isotopic Ratios: The isotopic composition of carbon in petroleum is similar to that of biological matter, which supports the idea that petroleum originates from the remains of ancient organisms. Abiogenic processes would likely produce a different isotopic signature.

2. Presence of Biomarkers: Biomarkers, such as hopanes and steranes, are specific to biological processes and are found in petroleum. Their presence indicates a biological origin.

3. Fossil Evidence: The presence of fossilized remains of plants and microorganisms in sedimentary rocks where petroleum is found supports the biogenic theory.

4. Laboratory Synthesis: It is difficult to synthesize significant amounts of hydrocarbons from inorganic materials under laboratory conditions that mimic the Earth's crust.

5. Geological Evidence: The distribution of petroleum reservoirs is often associated with sedimentary basins where organic-rich sediments have accumulated, suggesting a biological origin.

6. Microbial Life at Great Depths: The discovery of microbial life deep within the Earth's crust challenges the notion that petroleum could only originate from abiogenic processes.

7. Economic Viability: The abiogenic theory suggests that petroleum could be found in large quantities in the Earth's mantle, but the cost and difficulty of extracting it make this an uneconomic proposition.

8. Lack of Direct Evidence: There is a lack of direct evidence for abiogenic petroleum genesis, such as natural abiogenic hydrocarbon seeps from the mantle.

These counterarguments are supported by a wealth of scientific research and geological observations, leading to the widely accepted view that petroleum has a biogenic origin.