Which process involves fossilization where the original organic material is reduced to a film of carbon?

The process that involves fossilization where the original organic material is reduced to a film of carbon is carbonization. This occurs when an organism, typically a plant or an animal, is subjected to heat and pressure over time, leading to the removal of water and volatile components. As a result, a thin layer of carbon remains, preserving the fine details of the organism's structure.

This method of fossilization is significant because it allows for the preservation of original biological features in a simplified carbon form, making it easier to study and understand the organism's characteristics. In contrast, the other processes like petrification involve the replacement of organic material with minerals, while mineralization generally refers to the overall process of mineral deposition that can occur in various contexts, including but not limited to fossilization. Impression fossils create a mold or imprint of the organism rather than preserving any original organic material. Thus, carbonization specifically denotes the transformation into a carbon film, highlighting its unique role in the fossilization process.