An algorithm to aid varve counting and measurement from thin-sections

An algorithm has been implemented to count and measure laminations from digital images of petrographic thin-sections. Boundaries and limits of laminations are first marked manually using imaging software. These marks are then exported to a workable format output file. Using the output file, the algorithm extracts the relevant information for lamination counts and thickness measurements along one or more parallel vertical lines. Compared to manual counts, the use of the algorithm improves the accuracy of measurements and speeds up the process. The method requires tools commonly available in most laboratories, i.e., a digital camera or a flat bed scanner with transparency capability and a desktop computer with 64 MB of RAM. From the algorithm, two utilities are implemented in Visual Basic for Applications and Fortran to be used on both Apple Macintosh and a PC-compatible, with Adobe^® Photoshop^®.     

Revisiting sustainable development: Russian cultural and scientific traditions and the concept of sustainable development

The World Summit on Sustainable Development (26 August–4 September 2002), held in Johannesburg on the tenth anniversary of the first Earth Summit, provides the opportunity to reflect on the meaning of the sustainable development concept. This paper uses the case study of the Russian Federation to explore the relationship between official interpretations of sustainable development and alternative understandings concerned with the betterment of humankind, which draw on Russia's cultural and scientific heritage. It is suggested that there is much to be gained from reopening the sustainable development debate to incorporate such cultural particularities, both at the national and international levels.     

An investigation into the efficiency of particle size separation using Stokes’ Law

The accuracy of gravimetric fractionation as a means of obtaining size fractions from marine sediments has been explored. Analysis of the particle size distribution and sediment properties of fractions obtained using this method was undertaken. This has highlighted the extent to which experimental artefacts rather than variations in sediment characteristics may adversely affect the efficiency of the fractionation process. Copyright © 1999 John Wiley & Sons, Ltd.     

Problems of core correlation,sediment source ascription and yield estimation in Ponsonby Tarn,West Cumbria,UK

A suite of 27 short cores, 10 of which have been used for magnetic measurements and four for radiometric dating, provides a framework for reconstructing the processes, patterns and rates of sedimentation in Ponsonby Tarn, a small artificial impoundment created towards the end of the 19th century, close to the Sellafield nuclear reprocessing plant in NW England. Spatial and temporal changes in sedimentation are reconstructed and evidence presented for non-synchroneity in magnetic property changes from core to core in the upper part of the sequence, as a result of sorting and selective deposition at different distances from the inflow to the Tarn. Magnetic measurements alone are therefore not a secure basis upon which to quantify sediment yield for defined time intervals at this site. The chronology, established mainly from ²¹⁰Pb and ¹³⁴Cs analyses, allows estimates of mean sediment yield per annum for four periods: prior to AD 1940, 1940–1964, 1964–1986 and 1986–1991. The rates of sediment accumulation have increased in recent times, especially since 1964, with evidence for input from both magnetically enhanced soils and gleyed alluvial and/or podsolized subsoil sources. Pre-1940 mean annual deposition within the present area of the lake is calculated as 19·5 t a⁻¹ and for the period since 1986 (the period of maximum sedimentation rates), as 111·3 t a⁻¹. These represent yields of 7·0 t km⁻² a⁻¹ and 39·8 t km⁻² a⁻¹, respectively, for the catchment as a whole. Rock magnetic evidence, based on measurements of both bulk samples and the finest particle size separates, suggests that bacterial magnetite, formed within the lake, contributes to the magnetic properties of the sediments, thus modifying the signatures relating to allochthonous sediment input. Copyright © 1999 John Wiley & Sons, Ltd.     

Dating prehistoric bog-fires in northern England to calendar years by long-distance cross-matching of pine chronologies

The ages of prehistoric fires can be approximated by radiocarbon dating of charcoal or associated material, but such dating is often inaccurate and at best imprecise. Pine trunks preserved in British and Irish peats occasionally show firescars, which might be dated through dendrochronology to yield calendar-year dates. However, unlike oak, there is no master pine chronology to provide absolute dates, so dating is dependent on interspecies cross-matching; for sites in the British Isles with no dated oaks, calendar-year dating of prehistoric pines has hitherto proved impossible. We present a first success in dating, accurately and precisely, prehistoric fire events recorded in subfossil bog-pine trunks, using long-distance cross-matching of pine chronologies between White Moss, Cheshire, and the Humberhead Levels, England. Results demonstrate a bog-fire in Cheshire in spring 2800 BC, and again in 2710 BC, between spring and summer. Further successful long-distance cross-matching of pine would permit international climatological comparisons. © 1997 John Wiley & Sons, Ltd.     

Public Support for Land Acquisition: A Key Instrument for Successful Land Conservation,Governance and Management

While it is recognized that protected areas are important for biodiversity conservation and human wellbeing, governments struggle to establish and/or enlarge protected areas. Land acquisition and the challenges encountered by governing institutions in funding protected area systems expansion is discussed in this paper using the Capital Regional District (CRD) Land Acquisition Fund as a case study. We briefly discuss land acquisition in British Columbia and in the CRD, and offer an overview of the CRD Land Acquisition Fund and the public participation process that led to its establishment. We emphasize the importance of developing political and citizen support, and a shared vision about expanding protected areas systems - a key element for nearly doubling the parkland base of CRD Regional Parks in less than 20?years. We conclude by offering the lessons learned through the case study and provide guidance for policy and governance directions with regard to land acquisition.     

Incoherent Scatter Radar Studies of Daytime Plasma Lines

First results from wideband (electron phase energies of 5–51 eV), high-resolution (0.1 eV) spectral measurements of photoelectron–enhanced plasma lines made with the 430 MHz radar at Arecibo Observatory are presented. In the F region, photoelectrons produced by solar EUV line emissions (He II and Mg IX) give rise to plasma line spectral peaks/valleys. These and other structures occur within an enhancement zone extending from electron phase energies of 14–27 eV in both the bottomside and topside ionosphere. However, photoelectron–thermal electron Coulomb energy losses can lead to a broadened spectral structure with no resolved peaks in the topside ionosphere. The plasma line energy spectra obtained in the enhancement zone exhibit a unique relation in that phase energy is dependent on pitch angle; this relation does not exist in any other part of the energy spectrum. Moreover, large fluctuations in the difference frequency between the upshifted and downshifted plasma lines are evident in the 14–27 eV energy interval. At high phase energies near 51 eV the absolute intensities of photoelectron-excited Langmuir waves are much larger than those predicted by existing theory. The new measurements call for a revision/improvement of plasma line theory in several key areas.