Storm-dominated sedimentation along a rocky transgressive shoreline in the Silurian (Llandovery) of Western Ireland

Sedimentation patterns are described from the Kilbride Formation west of the Maam Fault zone, north Galway, Ireland. Seven distinct facies are described using faunal and lithological parameters. Environments of deposition range from marginal marine to deep shelf conditions. Lateral facies distributions were largely controlled by a rocky topographic high which influenced sedimentation until being buried by outer shelf sediments in middle-upper Kilbride Formation times. Four distinct sequences are described: in the lower Kilbride Formation, sequences I and IV are dominated by proximal storm deposits; sequence II was deposited in the lee of the topographic high and is interpreted as barred estuarine deposits; and in sequence III, at the topographic high, no deposition took place. In the upper Kilbride Formation the barrier was buried and uniform outer shelf conditions prevailed throughout the area. Faunal assemblages were strongly controlled by local environmental conditions and do not conform directly with the expected pattern of depth-related brachiopod communities. The Lingula and Eocoelia communities are amalgamated and alloch-thonous, the Pentameroides and Costistricklandia communities are absent, and only the Clorinda community is well represented, though parautochthonous.     

Rb-Sr isochron study of the Thorr and Main Donegal Granites,Ireland

A Rb-Sr whole-rock isochron study indicates that the entire Donegal granite suite was emplaced into orthotectonic Caledonian (Dalradian) rocks over a short interval during mid-Silurian to earliest-Devonian times. The Thorr pluton, probably the earliest member of the suite, yields an age of 418 ± 26 Myr and initial ⁸⁷Sr/⁸⁶Sr ratio of 0·7055 ± 4, while the latest member, the Main Donegal pluton has an age of 407 ± 23 Myr and initial ⁸⁷Sr/⁸⁶Sr ratio of 0·7063 ± 5 (Λ⁸⁷Rb = 1·42 ± 10⁻¹¹ yr⁻¹). Errors on both the age and initial Sr isotope ratios incorporate both a priori and geological scatter components and are quoted at the 2-sigma level. The low and restricted range of initial Sr isotope ratios suggests small but significant differences in the composition of the parental granitic magmas which were derived from a low Rb/Sr, low ⁸⁷Sr/⁸⁶Sr source.     

Residual relief separation: digital elevation model enhancement for geomorphological mapping

Geomorphologically mapped data form a primary set of observations that can be used to infer former environmental conditions. Thus, objective and consistent mapping of landforms from remotely sensed data (e.g. satellite imagery, digital elevation models (DEMs)) is paramount for reconstructing palaeoenvironments. This paper proposes a technique, ‘residual relief separation’, to enhance landforms in DEMs prior to visualization and digital mapping. This is applied to a ～600 km² region surrounding Lough Gara, Ireland, where drumlins (～200 m wide) overlie a regional relief of hills (～10 km wide). Here, residual relief separation uses this difference in width‐scale. Regional relief is approximated by a 1 km wide median filter, then subtracted to leave the drumlins in a ‘residual’ topography. In a second step, the residual relief is normalized to allow for amplitude variations in the drumlins across the area (～5–40 m high). Finally, visualization uses a simple black‐to‐white colour scale for height. Although not numerically outperforming other visualization techniques, this method performs equally well, and as the data are not ‘illuminated’ there is no azimuthal bias. Additional benefits include the relatively simple calculation, intuitive visual comprehension, no emphasis of noise, and the possibility of using any desired visualization technique after the landscape has been topographically manipulated. Copyright © 2008 John Wiley & Sons, Ltd.     

Landscape‐scale controls on the spatial distribution of caesium 137: A study based on an airborne geophysical survey across Northern Ireland

The spatial distribution of ¹³⁷Cs across the landscape and the processes controlling its redistribution are of interest because (i) ¹³⁷Cs has been widely used to quantify the movement of soil and sediments and (ii) substantial fallout of ¹³⁷Cs after the Chernobyl accident has led to contamination of foodstuffs in some places. A high‐resolution airborne geophysical radiometric survey of Northern Ireland has provided an opportunity to study the distribution and possible redistribution of ¹³⁷Cs. The ¹³⁷Cs activity (recorded at 1·2 million points) is distributed in a series of bands oriented approximately 160° and 115° clockwise from north. Geostatistical analysis of the data shows a strong, short‐range structure (correlation ranges between 0·6 and 8 km) in ¹³⁷Cs activity across the vast majority of the region; the spatial distribution shows association with a published, coarse‐scale depositional pattern of ¹³⁷Cs from Chernobyl. Two indices of land form derived from a digital elevation model, namely compound topographic index and the length–slope factor of the Revised Universal Soil Loss Equation, account for only 3% of the variance in ¹³⁷Cs activity. In contrast, soil type and land cover in combination (including their interaction) account for 20% of the variance. In areas that received moderate fallout from Chernobyl, soil type alone accounts for a substantial proportion of the spatially correlated ¹³⁷Cs activity. We attribute this to each soil type having a fairly uniform radiocaesium interception potential that differs from those of other soil types and that this potential controls the vertical migration of ¹³⁷Cs. Over the granitic Mourne Mountains there is a strong spatial cross‐correlation between ¹³⁷Cs activity and airborne estimates of soil potassium, suggesting that the latter provides a measure of the soil's radiocaesium interception potential; this is probably dominated by the quantity of the mineral illite. Copyright © 2010 John Wiley & Sons, Ltd. and British Geological Survey     

Coastal dune conservation on an Irish commonage: community-based management or tragedy of the commons?

In Ireland 'commonage' refers to lands jointly owned by several individuals who have grazing rights. Commonage can provide the low-intensity grazing regime regarded as optimal for habitat conservation, and it is also unlikely to suffer the negative impacts of building development or coastal engineering. Today, however, the traditional control systems of coastal commonage are generally moribund, leading to habitat degradation. The only viable future management model is likely to be one based on local community control. Community management would have the legitimacy to counter the negative perceptions of external authority that generate environmental degradation.     

爱尔兰矿业投资环境

爱尔兰是欧洲一个岛国,面积70273平方公里,人口约458万,是欧洲一个重要的铅锌矿生产国和出口国。爱尔兰铅锌矿成矿条件良好,政治稳定,法制总体较为健全,基础设施完善,矿业政策积极、稳定,矿业管理规范,矿业税费合理,与我国关系良好。尽管其矿业法律法规有待进一步完善,相关规定也有待进一步明确和细化,但总体来看,爱尔兰属矿业投资环境较良好的国家。     

Lower Carboniferous peritidal carbonates and associated evaporites adjacent to the Leinster Massif,southeast Irish Midlands

Analysis of a 275 m‐thick section in the Milford Borehole, GSI‐91‐25, from County Carlow, Ireland, has revealed an unusual sequence of shallow subtidal, peritidal and sabkha facies in rocks of mid?‐late Chadian to late Holkerian (Viséan, Lower Carboniferous) age. Sedimentation occurred on an inner ramp setting, adjacent to the Leinster Massif. The lower part of the sequence (late Chadian age) above the basal subtidal bioclastic unit is dominated by oolite sand facies associations. These include a lower regressive dolomitized, oolitic peloidal mobile shoal, and an upper, probably transgressive, backshoal oolite sand. A 68 m‐thick, well‐developed peritidal sequence is present between the oolitic intervals. These rocks consist of alternating stromatolitic fenestral mudstone, dolomite and organic shale, with evaporite pseudomorphs and subaerial exposure horizons containing pedogenic features. In the succeeding Arundian–Holkerian strata, transgressive–regressive carbonate units are recognized. These comprise high‐energy, backshoal subtidal cycles of argillaceous skeletal packstones, bioclastic grainstones with minor oolites and algal wackestones to grainstones and infrequent algal stromatolite horizons. The study recognizes for the first time the peritidal and sabkha deposits in Chadian rocks adjacent to the Leinster Massif in the eastern Irish Midlands. These strata appear to be coeval with similar evaporite‐bearing rocks in County Wexford that are developed on the southern margin of this landmass, and similar depositional facies exist further to the east in the South Wales Platform, south of St. George's Land, and in Belgium, south of the Brabant Massif. The presence of evaporites in the peritidal facies suggests that dense brines may have formed adjacent to the Leinster Massif. These fluids may have been involved in regional dolomitization of Chadian and possibly underlying Courceyan strata. They may also have been a source of high salinity fluids associated with nearby base‐metal sulphide deposits. Copyright © 2005 John Wiley & Sons, Ltd.     

Re-constructing the urban landscape through community mapping: an attractive prospect for sustainability?

Community mapping is a relatively new tool with considerable potential in giving practical effect at the local level to sustainable development rhetoric. As a repository of socially constructed knowledge, it has considerable value in democratizing information both in terms of what is recorded and public access to it, in a manner that facilitates more meaningful participation of non-experts in planning and advocacy processes. Focusing on a community mapping project in Galway, Ireland, this research paper explores how the city's municipal authority is employing community mapping not just to record and promote the city's social, environmental, economic and cultural assets but also as a practical tool to bolster public participation in policy-making and to improve local communities' trust in the municipal authority, thereby shaping sustainability practices through enhanced governance.     

Agriculturally induced environmental changes in the Burren Karst,Western Ireland

 The Burren plateau of County Clare is a classic example of a plateau karst characterised by patchy, thin soils, a lack of defined surface drainage, and in the instance of the Burren, a rich floristic, archaeological and landscape heritage. Since accession to the European Union and, in particular, as a result of Common Agricultural Policy initiatives, attempts have been made to raise farm incomes and to modernise agriculture in areas such as the Burren. Due to the encouragement of land reclamation and silage production has largely replaced hay farming for winter fodder. These changes pose a threat to groundwater quality by enhancing the leaching of artificial fertilizers or of organic pollutants. The Burren is highly vulnerable to water pollution from silage effluent because of its thin or absent soils and its highly karstified aquifers. A full survey of silage clamps was made in the summers of 1991 and 1992. For each site data were collected to derive the following: mass of silage, effluent produced, hazard rating of site to groundwater, likely discharge of effluent to groundwater and groundwater dilution index. About 60% of clamps were considered to be high risk and 23% medium risk. About 92% of all sites probably allow some effluent to infiltrate groundwater. Received: 1 June 1995 · Accepted: 4 December 1995