Suspended sediment transport and deposition in a high arctic meromictic lake

A study of sedimentary processes and sediment yields in a high arctic meromictic lake (Lake C2, Taconite Inlet, Northern Ellesemere Island, Canada) was undertaken from May 1990 through August 1992 to understand the links between climatic controls, hydrology, and the laminated sediment record preserved in the lake. Understanding the relationships between processes and the sediment record is critical for interpreting the climatic significance of the laminated sediments in a region where high resolution climate proxy records are quite limited.Sediment transport to Lake C2 is dominated by fluvial processes. During the early part of the melt season slushflows transport sediment to the lake surface. Subsequently, suspended sediment is delivered to the lake by the main inlet stream and distributed lakeward by a plume emanating the main inlet channel. Due to the strong density stratification of the water column the plume distributes sediment downlake by overflows and interflows in the epilimnion. In general, overflows are generated by lower discharge events whereas interflows penetrate to the halocline during high discharge with increased suspended sediment concentration.Sediment trap analysis demonstrates that suspended sediment transport and deposition responds to diurnal through annual changes in stream discharge. Seasonal and annual sediment trap yields agree with average accumulation rates determined from varve thickness measurements and cumulative suspended sediment discharge from the main inlet stream indicating a close link between climatological, hydrological, and sedimentological controls and varve deposition.This is the fourth in a series of papers published in this issue on the Taconite Inlet Lakes Project. These papers were collected by Dr R. S. Bradley.     

The shifting territory of government: some insights from the Rural White Paper

Summary In this paper it is proposed that the territory of governance is currently being reconfigured by the state. The state is pulling back from a universalist, welfare role, which entailed comprehensive governance of the whole national territory. Now a much more selective form of government is coming into being, concerned with 'community', 'diversity' and 'locality'. This is not, however, simply a belated recognition by the state that these are ever more important features of socio-spatial life: rather, it is part of the reconfiguration of the territory of government as the state invokes these characteristics in order to modify its ways of governing. Using Foucault's concept of governmentality–that is the means used by the state to 'problematise' life within its territorial borders and then act on the basis of these problematisations—the recent case of the Rural White Paper is examined. It is proposed that this is a very clear example of a governmental retreat from a comprehensive role in the governance of rural areas and shows how the state now seeks to govern 'through communities'.     

Trade Fair Educational Programs and Access to Knowledge: Evidence from the Solar PV Sector

In view of a globalizing marketplace and the continual need for market intelligence, firms seek venues in which to access cost effective, functional information. Significant sources of such knowledge, especially in tacit form, can be found within temporary clusters: international trade fairs. This article explores how firms in the solar photovoltaic (PV) industry use educational programs held during a trade fair as a means of information acquisition and exchange, providing a new angle to research on the economic geographies of these events, especially in terms of learning processes. Specifically, it analyzes how firms use educational programs to access remote knowledge (i.e., tacit information unavailable in a local context) in these temporary, spatially confined environments. Analyses of firm-level survey data gathered at a recent solar industry trade fair revealed that there is a significant effect of educational program participation on accessing remote knowledge. The results provide evidence that firms participate in trade fair educational programs to access remote knowledge that is critical to international success. Key Words: educational programs, knowledge exchange, remote knowledge, trade fairs.     

Percival Allen FRS (1917–2008): a personal tribute

This paper summarises the author's research association with Percival (‘Perce’) Allen FRS (1917–2008), whose wide-ranging and seminal contributions to Wealden (non-marine Lower Cretaceous) sedimentological and palaeoenvironmental interpretation spanned seven decades. The Geological Conservation Review (GCR) Special Issue on the Wealden was initiated as a collaborative research programme initiated during the late 1990s. Stemming from this, the GCR accounts are seen very much as the summation of Perce Allen's lifelong Wealden studies, as demonstrated by GCR sites throughout southern England.     

Floodgate Operations and Fish Communities in Tidal Creeks of the Lower Fraser River (British Columbia,Canada)

Tidal creeks in large coastal deltas can be important habitat for fish but are often highly modified by human activities. Connectivity between tributary creeks and mainstem channels is often constrained by structures such as dikes and floodgates, designed to protect urban and agricultural areas from flooding. While they play important roles in flood mitigation, floodgates can diminish habitat quality and block fish from accessing tidal creeks. It is likely that floodgates differ in their operations and may consequently open for different amounts of time; however, floodgate operations and their effects are not well quantified. We asked the question: how does the mechanical functioning of these floodgates affect fish communities in tidal creeks? We used time-lapse cameras and quantified the timing of gate openings for 22 tributaries of the Lower Fraser River in British Columbia, Canada, and related these operational data to differences in fish communities above and below floodgates. Floodgate operations varied substantially, with some floodgates opening daily while others opened less than 20% of the day, on average. Sites with floodgates that seldom opened were associated with greater differences in fish communities and with reduced upstream native species richness by about one species on average. Where floodgates opened infrequently, we also found lower upstream dissolved oxygen concentrations than at sites where floodgates opened for longer periods of time. Thus, floodgate operations can influence fish communities as well as water quality. These data indicate a large scope for improving floodgate operations for connectivity.     

Application of airborne LiDAR data and airborne multispectral imagery to structural mapping of the upper section of the Troodos ophiolite, Cyprus

Structural maps are traditionally produced by mapping features such as faults, folds, fabrics, fractures and joints in the field. However, large map areas and the spatially limited ground perspective of the field geologist can potentially increase the likelihood that not all structural features will be identified within a given area. The ability to recognise and map both local and regional structural features using high-resolution remote sensing data provides an opportunity to complement field-based mapping to help generate more comprehensive structural maps. Nonetheless, vegetation cover can adversely affect the extraction of structural information from remotely sensed data as it can mask the appearance of subtle spectral and geomorphological features that correspond to geological structures. This study investigates the utility of airborne Light Detection And Ranging (LiDAR) data and airborne multispectral imagery for detailed structural mapping in vegetated ophiolitic rocks and sedimentary cover of a section of the northern Troodos ophiolite, Cyprus. Visual enhancement techniques were applied to a 4-m airborne LiDAR digital terrain model and 4-m airborne multispectral imagery to assist the generation of structural lineament maps. Despite widespread vegetation cover, dykes and faults were recognisable as lineaments in both data sets, and the predominant strike trends of lineaments in all resulting maps were found to be in agreement with field-based structural data. Interestingly, prior to fieldwork, most lineaments were assumed to be faults, but were ground-verified as dykes instead, emphasising the importance of ground-truthing. Dyke and fault trends documented in this study define a pervasive structural fabric in the upper Troodos ophiolite that reflects the original sea-floor spreading history in the Larnaca graben. This structural fabric has not previously been observed in such detail and is likely to be continuous in adjacent regions under sedimentary cover. This information may be useful to future exploration efforts in the region focused on identification of structurally controlled mineral and groundwater resources. Overall, our case study highlights the efficacy of airborne LiDAR data and airborne multispectral imagery for extracting detailed and accurate structural information in hard-rock terrain to help complement field-based mapping.