Ichnofabric index explained

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] 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]

Notes and References

1. C. G.. R. J. . Response of the marine infauna to Triassic–Jurassic environmental change: Ichnological data from southern England . Palaeogeography, Palaeoclimatology, Palaeoecology . 244. Barras . 223–241 . 2007 . 10.1016/j.palaeo.2006.06.040. Twitchett. 1–4 . 2007PPP...244..223B .
2. Smail. M. F.. S. E. . A Semiquantitative Field Method for Evaluating Bioturbation on Bedding Planes . PALAIOS . 12. Miller. 4 . 391–396 . 1 August 1997 . 0883-1351. 10.2307/3515338. 3515338. 1997Palai..12..391M.
3. Droser . M.L. . Bottjer . D.J. . 1986 . A semiquantitative field classification of ichnofabric . Journal of Sedimentary Research . 56 . 4 . 558–559 . 10.1306/212f89c2-2b24-11d7-8648000102c1865d. 1986JSedR..56..558D .