The Abyssal Abiogenic Theory led to discoveries of oil in which rock type?

• A. In Sedimentary Basins
• B. In Shale Formations
• C. In Metamorphic Rocks
• D. In Non-sedimentary Crystalline Basement Rock

Answer: (D)

The idea being tested is a deep-Earth, abiotic source for hydrocarbons and where such hydrocarbons could plausibly occur. The Abyssal Abiogenic Theory suggests that oil and other hydrocarbons can form from inorganic carbon under extreme conditions deep in the Earth, and they could accumulate in rocks that are not traditional oil reservoirs. That points to non-sedimentary crystalline basement rocks—the ancient, solid crustal rocks like granites and other crystalline rocks at the base of continents—as potential hosts.

Most conventional oil forms in sedimentary basins where organic-rich sediments have been deposited, transformed, and later trapped in sedimentary rocks such as sandstone, limestone, or shale. Under the abiogenic view, finding oil in crystalline basement rocks would align with the idea that hydrocarbons can originate and be stored in deep, non-sedimentary rock, which is why this rock type is the best fit for the question.