Page "Vitrinite" Paragraph 1

The vitrinite group, which consists of various individual vitrinite macerals, is the most common component of coals.

It is also abundant in kerogens that are derived from the same biogenic precursors as coals, namely land plants and humic peats.

Vitrinite forms diagenetically by the thermal alteration of lignin and cellulose in plant cell walls.

It is therefore common in sedimentary rocks that are rich in organic matter, such as shales and marls with a terrigenous origin, or some terrigenous content.

Conversely, carbonates, evaporites and well-sorted sandstones have very low vitrinite contents.

Vitrinite is absent in pre-Silurian rocks because land plants had not yet evolved.