Statistics and Data Analysis in Geology

We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical–biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not been widely implemented in sandy beaches, could be a key tool for biodiversity conservation and should also facilitate spillover effects into adjacent beach habitats. Setback and zoning strategies need to be enforced through legislation, and all relevant stakeholders should be included in the design, implementation and institutionalisation of these initiatives. New perspectives for rational management of sandy beaches require paradigm shifts, by including not only basic ecosystem principles, but also incentives for effective governance and sharing of management roles between government and local stakeholders.

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Threats to sandy beach ecosystems: A review

INTROdu CTION Warm mix asphalt (WMA) has been gaining acceptance across the United States and Canada in recent years. A large number of state departments of transportation (DOTs) have hosted WMA demonstrations to determine if WMA should be allowed for state-funded paving projects. These demonstrations have shown that WMA is constructible and can reduce fuel usage and emissions associated with hot mix asphalt (HMA) production. However, many of these demonstrations were conducted with only one or two WMA technologies. Now there are over 25 commercially available WMA technologies in the United States. Most states do not approve a WMA technology for use on state-maintained roads without a welldocumented demonstration project. The WMA technology suppliers that were not part of these early demonstration projects often are required to organize a demonstration on their own to gain approval for state paving projects. A standard evaluation program for con

NAtioNAl CooperAtive HigHwAy reseArCH progrAm

H. H. Lamb's latest book on the earth's changing climate is a carefully crafted work covering four areas: the physical basis of climate and climate change, the methods of climate reconstruction, the history of climate since the height of the last glaciation, and the impact of climate on human affairs. The book will be of particular interest to three groups. Atmospheric scientists interested in the long history of climate behavior (but perhaps overwhelmed by Lamb's all-encompassing work on the topic, Climate: Past, Present and Future, vol. II, Methuen, New York), will find Climate History and the Modern World to be a good titration of the fuller work. Scientists in other fields, including social scientists grappling with issues of climate-society interaction, will find the book a good entree into the field. Finally, Lamb himself suggests that the book will be useful to resource managers and other decision makers trying to avoid negative climate impacts. With this last audience in mind, no doubt, Lamb has chosen a style that eschews extensive footnoting and references (though sufficient citations are included to lead to further information). This works quite well and seems reasonable in view of his carefully documented previous writings.

Climate History and the Modern World

Use of indicators and pore volume-function characteristics to quantify soil physical quality

Grain size analysis is an essential tool for classifying sedimentary environments. The calculation of statistics for many samples can, however, be a laborious process. A computer program called GRADISTAT has been written for the rapid analysis of grain size statistics from any of the standard measuring techniques, such as sieving and laser granulometry. Mean, mode, sorting, skewness and other statistics are calculated arithmetically and geometrically (in metric units) and logarithmically (in phi units) using moment and Folk and Ward graphical methods. Method comparison has allowed Folk and Ward descriptive terms to be assigned to moments statistics. Results indicate that Folk and Ward measures, expressed in metric units, appear to provide the most robust basis for routine comparisons of compositionally variable sediments. The program runs within the Microsoft Excel spreadsheet package and is extremely versatile, accepting standard and non-standard size data, and producing a range of graphical outputs including frequency and ternary plots. Copyright © 2001 John Wiley & Sons, Ltd.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/esp.261

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

Shape is a fundamental property of all objects, including sedimentary particles, but it remains one of the most difficult to characterize and quantify for all but the simplest of shapes. Despite a large literature on the subject, there remains widespread confusion regarding the meaning and relative value of different measures of particle shape. This paper re-examines the basic concepts of particle shape and suggests a number of new and modified methods which are widely applicable to a range of sedimentological problems; it is shown that the most important aspects of particle form are represented by the I/L ratio (elongation ratio) and S/I ratio (flatness ratio). A combination of these two ratios can be used to classify particles in terms of 25 form classes. A method of obtaining a quantitative measure of particle roundness using simple image analysis software is described, and a new visual roundness comparator is presented. It is recommended that measurements of both roundness and circularity (a proxy measure of sphericity) are made on grain images in three orthogonal orientations and average values calculated for each particle. A further shape property, irregularity, is defined and a classification scheme proposed for use in describing and comparing irregular or branching sedimentary particles such as chert and coral.

Particle shape: a review and new methods of characterization and classification

This paper provides a review of different particle size scales, size class terminology and particle size distribution (‘textural’) classification schemes which are widely used in sedimentology, geomorphology, soil science, aquatic ecology and civil engineering It is concluded that a revised system of size class nomenclature, based on the Udden (1898) and Wentworth (1922) schemes, provides the most logical and consistent framework for use with sediments and a wide range of other particulate materials A refined scheme is proposed which has five first-order size classes (boulder, gravel, sand, silt and clay), each of which has five second-order subdivisions with limits defined at one phi intervals The scheme is simple and intuitively easy to understand The paper also provides a review of previous schemes that have been proposed to describe and classify sediments on the basis of the proportions of gravel, sand and mud, or sand, silt and clay using trigons (also termed ternary diagrams) Many of these schemes do not have a logical basis and provide limited or uneven resolution New gravel, sand and mud and sand, silt and clay classification systems are proposed that are both more logical and provide greater discriminatory power than previous schemes; they are therefore more suitable for use in environmental and forensic investigations A new Microsoft Excel® program, freely available to download from http://wwwkpalcouk, allows rapid classification of sediments based on the proportions of gravel, sand and mud and sand, silt and clay proportions and graphical comparison of the data for different sample groups

Particle size scales and classification of sediment types based on particle size distributions: review and recommended procedures.

Beach–dune morphological relationships and erosion/accretion: An investigation at five sites in England and Wales using LIDAR data

Laser diffraction is now widely used for particle size distribution analysis of sediments and soils. The technique can be very precise, and offers advantages of speed and cost over many other methods when used to analyse mixtures of sand, silt and clay. This study presents the results of an experimental investigation that examined the sensitivity of the Beckman-Coulter LS230 instrument to mixtures of different grain populations and differences in particle shape. The instrument was found to have high sensitivity to coarse particles in a finer matrix (detection threshold 1–2%), but much lower sensitivity to finer particles in a coarser mixture (detection threshold 12–17%). Experiments using near-spherical ballotini showed that laser analysis provides very similar values to dry sieving for the mean, median and mode, but for a range of natural sand samples values for the mean, median and mode were offset by 8–21%, with an average of ca 15%, compared with sieving. Analysis using a Beckman-Coulter RapidVUE instrument, which provides both size and shape information, provided support for the hypothesis that the differences between laser analysis and sieving are partly attributable to the effects of particle shape. However, an additional factor is the way in which the laser software interprets the optical diffraction data. The software predicts a high degree of log-normality in the size distribution, such that highly skewed, truncated or bimodal samples are poorly represented. Experiments using sieved fractions of ballotini indicated that, even with near-perfectly spherical particles, the particle size distribution predicted by the laser software includes a relatively large percentage of particles outside the sieve class limits.

Particle size distribution analysis of sand-sized particles by laser diffraction: an experimental investigation of instrument sensitivity and the effects of particle shape

Simon J. Blott

Papers

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

Particle shape: a review and new methods of characterization and classification

Particle size scales and classification of sediment types based on particle size distributions: review and recommended procedures.

Beach–dune morphological relationships and erosion/accretion: An investigation at five sites in England and Wales using LIDAR data

Particle size distribution analysis of sand-sized particles by laser diffraction: an experimental investigation of instrument sensitivity and the effects of particle shape