Ichnofabric index

The Droser-Bottjer ichnofabric index is a method used to quantify the degree of bioturbation in a sedimentary rock.

It involves grading the amount of trace fossil activity on a scale of 1–6; a value of 1 indicates that bioturbation is entirely absent, whereas the highest grade would involve a bedding plane containing over 60% trace fossil cover.

[1] Ichnofabric index can be applied in either a vertical or horizontal aspect.

The vertical component provides an indication of the interplay between physical and chemical aspects of the environment and the degree of biological activity.

[2] The vertical ichnofossil index is harder to measure; it involves quantifying the amount of disturbance to the original sedimentary fabric.