Review: Stratigraphy, meta-stratigraphy and chaos

An alternative approach to stratigraphic analysis is proposed. It takes as its starting po int the simple general characteristics of the stratigraphic record and the complex, chaotic behaviours of the systems that combine to generate this record. in this context, Smith's Stratigraphy Machine (SM) co ncept is developed. The SM is a chaotic global system, combining the operat ions of the atmosphere, hydrosphere, lithosphere and asthenosphere, which e verywhere tends to self-organize towards a critical state in which continuo us loading of the system with rock waste, over time, is balanced by the unl oading that creates the record. The outputs of the SM are simple and nonsca le dependent in character, with residence times in the record ranging from a second, or less, to 1 billion years. However, only those long-lived in th e human time-frame are judged to be of stratigraphic significance; and the range of residence times entails that the stratigraphic record embraces a s imilar range of hiatuses, or gaps. The value of the SM, as developed here, is that it can he regarded as a met a-stratigraphic concept that transcends the usual frameworks of stratigraph ic classification and interpretation and thus allows a reappraisal of signi ficant features of the record such as its perceived cycles and sequences. T here are three outcomes of this meta-stratigraphic analysis. First. the geo metric units employed in sequence stratigraphy are components of a self-sim ilar series of essentially lenticular bodies, with no fundamental character istics to distinguish them from larger and smaller bodies in the generally self-similar series. Secondly, the interactions and feedbacks within the SM are so complex, and its outputs so repetitive in general character, that i t is dangerous to assume that any perceived cyclicity provides an unambiguo us chronicle of process cyclicity, whether eustatic, climatic or tectonic. The classic coarsening upward cyclicity of shallow marine facies can, for e xample, be viewed solely as the outcome of the lack of phasing between the chaotic behaviours tending to unload the SM and those creating accommodatio n space. Finally the meta-stratigraphic approach reinforces the view that, in the absence of demonstrable stratal continuity, chronostratigraphic corr elation must continue to rely on sample-based, mainly biostratigraphical, m ethods, rather than sequence stratigraphy.