Strata and Time: Probing the Gaps in our Understanding, edited by D.G. Smith, R.J. Bailey, P.M. Burgess and A.J. Fraser. Geological Society, London, Special Publication, 404, 2015. No. of pages: vii+325. Price: UK £120.00. ISBN 978-1-86239-655-5 (hardback).

Abstract

This volume originated from a William Smith Meeting held in September 2012. Its major aim was to discuss and describe the relationship between the observed sedimentary rock record and the passage of geological time, identifying, evaluating and updating those models that lie behind the current stratigraphic methods. Ager's phrase, there will be ‘more gaps than record’, is shown to be correct in several papers. This volume includes 15 papers, excluding the introductory paper by Smith et al., ‘Strata and Time: probing the gaps in our understanding’. This is an engaging paper, including a useful discussion of other papers in this book. The volume is divided into four sections, the first dealing with continuity, completeness and the Geologic Time Scale. Miall discusses updating uniformitarianism and defining a suite of sedimentation rate scales, which incorporate the range of time scales and processes within the stratigraphic record. Smith et al. review the Global Boundary Stratotype Section and Point (GSSP) procedures. Their main recommendations are that the GSSPs should also incorporate physico-chemical markers, as well as their current primary biostratigraphic datums, plus the inclusion of more stratigraphic sections. The second section, ‘Gaps, Fractals and Scaling’, includes three papers. Sadler and Jerolmack discuss scaling laws for aggradation, denudation and progradation rates, using newly complied global data. The authors argue that there is a fractal relationship between the number and the duration of hiatuses in the geological record. Bailey describes the power law attributes of stratigraphic layering and their possible significance, discussing All Returns Analysis and the Layer Thickness Inventory, plus the significance of the Power Laws. Tipper discusses stasis in sedimentation systems and its stratigraphic effects. Contributions within the third section, ‘Stratal Hierarchies and Cycles’, include Pollitt et al. examining and discussing the occurrence of hierarchies of cyclicity in platform carbonates. Vaughan et al. discuss data filtering as a source of spurious spectral peaks within cyclostratigraphy. Hilgen et al. consider ‘Stratigraphic Continuity and Fragmentary Sedimentation: the success of Cyclostratigraphy as part of Integrated Stratigraphy’, with an extensive discussion on Milankovitch cyclicity within the fossil record. The last section is ‘Strata and Time in the Field and Subsurface’ and includes several papers (not all discussed herein), including a detailed study of the Bridport Sands by Hampson et al., which encompasses datasets from outcrop, subcrop, wireline log data and seismic data to enhance their depositional and reservoir model. Plotnick et al. (‘Using the voids to fill the gaps: caves, time and stratigraphy’) discuss the stratigraphic record of caves and karst, and the recovered fossils contained within these settings. Crossley and Clark discuss ‘More gap than record?’, contrasting two field sections: the shallow-water Llandovery Pentamerus Beds of Shropshire, UK, and the more distal Lower Ordovician Ribband Group, County Wexford, Ireland. The former show marked time gaps within the succession, while the latter sedimentary sequence exhibits little or no apparent major time gaps. Large and Marshall discuss the use of carbon accumulation rates to estimate the duration of coal seams and the influence of atmospheric dust deposition on coal composition. As with many of the volumes published by the Geological Society, this book contains a wealth of information and a lot of detailed research. There is something for everybody. I would strongly recommend it for undergraduates, postgraduates, academics and any worker who has an interest in (sequence) stratigraphy (including geophysicists).