Fossil Wiki

Trace fossils occupy a large proportion of this bedding plane.

The ichnofabric index is a method used to quantify the degree of bioturbation in a sedimentary rock. It involved grading the amount of trace fossil activity on a scale of 1–5; 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] This 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.[3]


  1. ^ Barras, Colin G. (2007). "Response of the marine infauna to Triassic–Jurassic environmental change: Ichnological data from southern England". Palaeogeography Palaeoclimatology Palaeoecology 244: 223. doi:10.1016/j.palaeo.2006.06.040.
  2. ^ Miller, Molly F. (1997). "A Semiquantitative Field Method for Evaluating Bioturbation on Bedding Planes". Palaios 12: 391. doi:10.2307/3515338.
  3. ^ Droser, M.L.; Bottjer, D.J. (1986), "A semiquantitative field classification of ichnofabric", Journal of Sedimentary Research 56 (4): 558–559, 

Dinosaur State Park (Rocky Hill, CT) - close-up.JPG