Biogenic origin of coastal honeycomb weathering

Honeycomb weathering occurs in two environments in Late Cretaceous and Eocene sandstone outcrops along the coastlines of south‐west Oregon and north‐west Washington, USA, and south‐west British Columbia, Canada. At these sites honeycomb weathering is found on subhorizontal rock surfaces in the intertidal zone, and on steep faces in the salt spray zone above the mean high tide level. In both environments, cavity development is initiated by salt weathering. In the intertidal zone, cavity shapes and sizes are primarily controlled by wetting/drying cycles, and the rate of development greatly diminishes when cavities reach a critical size where the amount of seawater left by receding tides is so great that evaporation no longer produces saturated solutions. Encrustations of algae or barnacles may also inhibit cavity enlargement. In the supratidal spray zone, honeycomb weathering results from a dynamic balance between the corrosive action of salt and the protective effects of endolithic microbes. Subtle environmental shifts may cause honeycomb cavity patterns to continue to develop, to become stable, or to coalesce to produce a barren surface. Cavity patterns produced by complex interactions between inorganic processes and biologic activity provide a geological model of ‘self‐organization’. Surface hardening is not a factor in honeycomb formation at these study sites. Salt weathering in coastal environments is an intermittently active process that requires particular wind and tidal conditions to provide a supply of salt water, and temperature and humidity conditions that cause evaporation. Under these conditions, salt residues may be detectable in honeycomb‐weathered rock, but absent at other times. Honeycomb weathering can form in only a few decades, but erosion rates are retarded in areas of the rock that contain cavity patterns relative to adjacent non‐honeycombed surfaces. Copyright © 2010 John Wiley & Sons, Ltd.     

Modelling changes in the epidemic range of Southern Pine Beetle using temperature and objective moisture indicators

Summary This report details as statistical model that relates changes in areal coverage of the Southern Pine Beetle (Dendroctonus frontalis Zimm.) to a multivariate combination of temperature and moisture status indices. It is applicable to larger geographic areas than our previous work (Michaels 1984). Performance in a true test (predictive) mode detected the algebraic sign of major coverage changes in a highly significant fashion. The results are purely correlative, rather than causative.This report describes a test-proven tool that can be used by planners to determine whether coverage will change, based upon easily accessed climatic data. An example of its application is provided.

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Zusammenfassung Diese Untersuchung führt ein statistisches Modell aus, welches das flächenmäßige Auftreten vonDendroctonus frontalis Zimm. mit einer Kombination von Temperaturund Feuchteverhältnisindikatoren in Verbindung bringt. Es kann für größere Gebiete verwendet werden als ein früher vorgestelltes (Michaels 1984). Die Anwendung zur Vorhersage zeigte in einem Test gute Übereinstimmung mit der tatsächlich aufgetretenen Richtung der Veränderung in der Verbreitung des Käfers. Die Ergebnisse zeigen Korrelationen, keine Kausalitäten auf.Es wird also ein Werkzeug für den Planer vorgestellt, mit dem die Verbreitungsänderung mit Hilfe leicht zugänglicher klimatologischer Daten bestimmt werden kann. Ein Anwendungsbeispiel wird näher ausgeführt.

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With 5 Figures     

Meteorological and synoptic aspects of the formation and evolution of the Novorossiysk Bora

The genetic and synoptic classifications of the Novorossiysk Bora are created using the data of daily observations at the Novorossiysk meteorological station and other available synoptic information. Obtained are the quantitative criteria of these classifications, and on this base worked out are the basic scenarios of the generation and evolution of this dangerous phenomenon on the Black Sea coast of Russia. According to the genetic classification, the Bora was divided into four types: frontal, air-mass, monsoon, and gravity. Quantitative criteria worked out for each type can be used for the more accurate forecast of this destructive phenomenon near Novorossiysk. According to the synoptic classification, four classes were distinguished: Azores, North Atlantic, Siberian, and Arctic.     

Structural characteristics of zooplankton of the Shardarinskoe Reservoir and their use in water quality assessment

Data on the Shardarinskoe Reservoir are used to assess the indicator role of zooplankton community under unstable hydrological regime. The structural characteristics of zooplankton featured significant seasonal variations. The averaged indices characterized reservoir water quality at the level of mesotrophic and eutrophic water bodies. The possible use of cyclopidas to characterize toxic pollution of water is discussed.     

Fault structures and their geoelectric parameters in the epicentral zone of the 27 September 2003 Chuya earthquake (Gorny Altai) from resistivity data

This paper presents an integrated measurement technique based on DC methods (vertical electrical sounding, electrical resistivity tomography) which was used to identify faults and determine their geoelectric parameters in the western part of the Chuya basin. New information on the structure of the Chagan River valley located in the zone of the disastrous 27 September 2003 Chuya earthquake has been obtained from the results of these methods. Geoelectric cross-sections of the sedimentary sequence and the upper part of the basement were obtained from VES data, showing the block structure of the study area. Electrical resistivity tomography sections confirm the presence of a major fault between basement blocks of different heights and indicate the presence of faults bounding the valley on its right side and in the southwestern part.     

Engineering problems associated with expansive clays from Romania

Engineering problems associated with expansive clay formations, which have a large swelling and shrinking potential, exist in different regions of Romania.In the general framework of the study of the behaviour of expansive clays, the present paper describes some particular aspects connected with the swelling and shrinkage processes and their engineering effects in Romania.The differences between swelling potential relationships, obtained by two different methods are presented and discussed. Swelling pressure tests were accomplished using the available standard techniques, as well as a specially developed cell pressure equipment.Attention is drawn to the stages of the shrinkage process as related to soil structure. It was found that, in a general case, there are three distinct?tages: initial, normal and residual shrinkage.Laboratory investigations have shown that in soils with an anisotropic structure, the directional variation of shrinkage strains is elliptical in shape, with the maximum shrinkage normal to particle orientation.The engineering aspects of the results are discussed.