Darwin would be proud: Bioturbation, dynamic denudation, and the power of theory in science



Charles Darwin's worm book influenced many early researchers who, following his lead, demonstrated how soil biota mechanically generate new strata and soil horizons, as well as blur or destroy them. Such early observations on biomechanical processes failed to find visibility in our models of landscape evolution for several reasons, chief of which are (1) except for ichnology, an Earth sciences tradition of adopting frameworks where biomechanical processes are absent and (2) a lapse of over 100 years after Darwin before a genetic language backed by supporting theory appeared that could showcase the importance of such processes. Examples of influential Earth science frameworks in which biomechanical processes are absent are the V.V. Dokuchaev–USDA–H. Jenny soil formational (five factors) paradigm, W.M. Davis' geographical cycle, the W. Penck–L.C. King–R.V. Ruhe backwasting-pedimentation concept, the stratigraphic Law of Superposition, and other traditional approaches to archaeology, geomorphology, and pedology. Examples of recent genetic language that serve to ameliorate the problem are soil thickness concepts, biomantle, bioturbation, faunalturbation, floralturbation, and pedoturbation. Examples of recent supporting theory that incorporate biomechanical processes are soil evolution, biomantle evolution, dynamic pedogenesis, and the dynamic denudation framework advocated here. Dynamic denudation is a unified synthesis that elevates bioturbation to parity levels with other major archaeogenic, geomorphogenic, and pedogenic processes. The general framework and its principal elements are summarized and simulated by diagrams and augmented by photographs taken in disparate parts of the world. The model has useful explanatory and predictive value in archaeology, geomorphology, pedology, and other surficial process research. © 2002 John Wiley & Sons, Inc.