North Coast Of Northern Ireland Research Articles

Lower Jurassic (Hettangian–Pliensbachian) microfossil biostratigraphy of the Ballinlea-1 well, Rathlin Basin, Northern Ireland, United Kingdom

The thickest section of Early Jurassic strata known from onshore Ireland (total Jurassic thickness 566 m) is reported from the Ballinlea-1 well (Rathlin Basin) situated on the north coast of Northern Ireland. A biostratigraphical and palaeoenvironmental assessment is presented for this section largely based on calcareous benthic microfossils (foraminifera and ostracods). The Early Jurassic Waterloo Mudstone Formation (Lias Group) of Northern Ireland has previously received little micropalaeontological attention, therefore this work provides an opportunity to enhance palaeogeographic and palaeoenvironmental understanding for the Early Jurassic of the province, and this paper illustrates the key microfossil taxa of this age from Ireland for the first time. The records, based on ditch-cuttings samples, demonstrate a stratigraphical range from Hettangian to Early Pliensbachian, consistent with other wells and boreholes in this basin. The assemblage compositions are comparable to those elsewhere in the European boreal Atlantic realm. Hettangian to earliest Sinemurian microfossil assemblages are generally of low diversity and are numerically dominated by metacopid ostracods with occasional influxes of foraminifera. Gradually, foraminiferal abundance (often dominated by species of the Lagenida) come to exceed those of the ostracods in the Early Sinemurian reaching their greatest diversity in the Late Sinemurian. The sediments are considered to represent an inner to mid-shelf environment throughout while the record thickness for this region indicates ongoing syn-sedimentary fault movement along the basin margins within this period.

Spatial Variability of Beach Impact from Post-Tropical Cyclone Katia (2011) on Northern Ireland’s North Coast

In northern Europe, beach erosion, coastal flooding and associated damages to engineering structures are linked to mid-latitude storms that form through cyclogenesis and post-tropical cyclones, when a tropical cyclone moves north from its tropical origin. The present work analyses the hydrodynamic forcing and morphological changes observed at three beaches in the north coast of Northern Ireland (Magilligan, Portrush West’s southern and northern sectors, and Whiterocks), prior to, during, and immediately after post-tropical cyclone Katia. Katia was the second major hurricane of the active 2011 Atlantic hurricane season and impacted the British Isles on the 12–13 September 2011. During the Katia event, offshore wave buoys recorded values in excess of 5 m at the peak of the storm on the 13 September, but nearshore significant wave height ranged from 1 to 3 m, reflecting relevant wave energy dissipation across an extensive and shallow continental shelf. This was especially so at Magilligan, where widespread refraction and attenuation led to reduced shore-normal energy fluxes and very minor morphological changes. Morphological changes were restricted to upper beach erosion and flattening of the foreshore. Longshore transport was evident at Portrush West, with the northern sector experiencing erosion while the southern sector accreted, inducing a short-term rotational response in this embayment. In Whiterocks, berm erosion contributed to a general beach flattening and this resulted in an overall accretion due to sediment influx from the updrift western areas. Taking into account that the post-tropical cyclone Katia produced £100 m ($157 million, 2011 USD) in damage in the United Kingdom alone, the results of the present study represent a contribution to the general database of post-tropical storm response on Northern European coastlines, informing coastal response prediction and damage mitigation.

Age and palaeoenvironmental significance of an inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry

A recently exposed inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry, has yielded new information about mid-Holocene coastal environmental change in the north-east of Ireland. Pollen analytical data and wood detritus demonstrate that peat accumulation occurred in a terrestrial environment that was free from marine influence. Radiocarbon dates suggest that the peat accumulated rapidly during a period of low relative sea level subsequent to the maximum of Holocene relative sea-level rise along the north coast of Northern Ireland. The absence of marine/brackish indicator taxa at the site suggests that the tidal range was somewhat less than that at present and/or that the channel of the river was located some distance east of its present alignment. The dates indicate that the low stand lasted for at least ~0.2 ka and possibly for ~1.1 ka. Stable, woodland-dominated landscapes are indicated at both this site and neighbouring ones around ~6.4-5.3 cal ka BP. There is no evidence for large-scale aeolian sand movement or human impact on the landscape during the period of peat accumulation.

Age and palaeoenvironmental significance of an inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry

Abstract A recently exposed inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry, has yielded new information about mid-Holocene coastal environmental change in the north-east of Ireland. Pollen analytical data and wood detritus demonstrate that peat accumulation occurred in a terrestrial environment that was free from marine influence. Radiocarbon dates suggest that the peat accumulated rapidly during a period of low relative sea level subsequent to the maximum of Holocene relative sea-level rise along the north coast of Northern Ireland. The absence of marine/brackish indicator taxa at the site suggests that the tidal range was somewhat less than that at present and/or that the channel of the river was located some distance east of its present alignment. The dates indicate that the low stand lasted for at least~0.2 ka and possibly for~1.1 ka. Stable, woodland-dominated landscapes are indicated at both this site and neighbouring ones around~6.4–5.3 cal ka BP. There is no evidence for large-...

Wave-Sediment Interactions on an High Energy Beach System

Please click here to download the map associated with this article. The North coast of Northern Ireland is exposed to high-energy swells and frequent storm events and therefore beach systems found along this coast tend largely to be dissipative in character. Bedrock-framed coastlines formed by basalt cliffs, shore platforms and smaller sandy embayments dominate this study area. West Strand beach at Portrush (located 55°12′N/6°40′W) is a high-energy system shaped by a headland-embayment with a sandy beach to the north and boulder beach to the south. It is characterised by a microtidal regime and predominant local winds are west and south westerly. The research work aims to examine this high-energy beach under multiple storm scenarios and to investigate hydrodynamic and morphodynamic behaviour at the site. For the analysis, a wave propagation model was used to compare wave energy dissipation from storm wave events as well as examining currents and sediment transport through the analysis of the spatial distribution of radiation stress. Real data from deep-water wave parameters (significant wave height, period and direction), wind direction and speed, and recent high-resolution bathymetry data were used as an input to the propagation model. The methodology was applied to West Strand beach (9 km2) at a scale of 1:250.

Temperature effects on copper-clad brickwork dome roof

This paper describes an experimental investigation that involved the monitoring of crack movements in the copper-clad brickwork dome roof of an historic building known as Mussenden Temple—a National Trust property located on the north coast of Northern Ireland. An automatic strain measurement instrumentation system was installed which enabled monitoring of crack movements and temperatures at hourly intervals over a four year monitoring period. The data collected over this period is summarised and some interesting conclusions are drawn. It is hoped that the findings of this research will be useful in the assessment of other historic buildings and structures.

Mid-to late-Holocene coastal dune event stratigraphy for the north coast of Northern Ireland

An event stratigraphy of dune stability/instability phases has been reconstructed, using 22 radiocarbon and 13 luminescence dates, for six dunefields along the north coast of Northern Ireland. There is no evidence for dune development prior to ċ. 7000 cal. years BP, during the early-Holocene rapid rise in RSL, and only limited evidence for sand accumulation in association with the RSL maximum. Dunefield dates correspond to either the subsequent regressive phase or, later, the gradual transgressive phase of RSL history in the mid-and late Holocene. At these times accommodation space for dune development and sediment supply were maximized. Episodes of climatic deterioration, particularly at 3100–2400 cal. years BP and 650–50 cal. years BP (the‘Little Ice Age’) were marked by widespread dune instability. A similar coincidence in timing has been recorded for dune systems elsewhere in northwestern Europe and is generally attributed to an increased frequency of storms and storm surges associated with the climatic downturns. However, between-site inconsistencies in the event stratigraphy suggest that site-specific factors (e.g., sediment availability) had a modulating influence on dune regional controls.

Stratigraphy of Maastrichtian Foraminiferida from the United Kingdom; the Maastrichtian of Norfolk

AbstractOnshore Maastrichtian strata in the United Kingdom are limited to a few small, isolated blocks of chalk floating within glacial sediments on the Norfolk coast. Isolated outcrops of Campanian and Maastrichtian chalks used to be available around Norwich but the majority of these exposures are now badly degraded. Offshore, in the North Sea Basin, there are complete chalk successions that range throughout the Upper Cretaceous and Lower Cenozoic. There is a limited succession of Maastrichtian chalks exposed on the north coast of Northern Ireland below the Cenozoic flood basalts. In the Western Approaches Basin, Maastrichtian and Danian chalks are known from exploration wells and core samples. West of the United Kingdom a number of DSDP/ODP boreholes have penetrated the Upper Cretaceous succession.Beginning in the Cenomanian, in southeast England, the whole of the Upper Cretaceous is within the chalk facies, possibly one of the longest intervals of relatively stable environment in the geological record. The Foraminiferida of the chalk have been studied for more than a hundred years and therefore the fauna is exceptionally well known and fully documented. Fifty years ago, the benthonic Foraminiferida were identified as having the potential to provide a viable zonation of the chalk facies and we now have precise, cross-basinal correlation using these taxa.The planktonic fauna is restricted by both palaeolatitude and water depth. The latter appears to be the most influential as the faunas from onshore are more limited than those recorded from the deeper waters of the North Sea Basin and the Atlantic Margin. Even with this restricted fauna, however, it is still possible to develop a general correlation with the standard Tethyan zonation based on planktonic taxa.

Inner shelf seismic stratigraphy off the north coast of Northern Ireland: new data on the depth of the Holocene lowstand

New seismic stratigraphic data are presented from the inner shelf off the north coast of Northern Ireland. The sequence preserved comprises an acoustic basement of till or solid bedrock, overlain by a fine-grained, acoustically transparent unit interpreted as glacio-marine sediment. This is overlain by an upper, reflective sandy unit which contains a discontinuous but widespread internal reflector, interpreted as peat that developed during a late glacial/Holocene relative sea-level fall and continued to accumulate until subsequent inundation. The depth of the Holocene lowstand is estimated at −30 m MSL on the basis of the seaward extent of the sandy unit and its intercalated peaty horizons, the presence of erosional notches and a widespread break in slope at this depth. The lowstand is not definitively dated but on the basis of dated deposits in adjacent locations is inferred to have occurred between 10 000 and 11 000 14C yr BP.

High-resolution geophysical investigations of estuarine and nearshore sediment dynamics, River Bann estuary, Northern Ireland coast.

The River Bann, Northern Ireland, discharges onto the high-wave energy, swell-dominated North Atlantic coast. The funnel-shaped estuary, buttressed by Tertiary basalt outcrops, is partially barred by dunes developed on a mid-Holocene gravel barrier. The meso-scale evolution of the estuary and nearshore zone therefore demonstrates the interaction of fluvial, marine and coastal processes. Echo sounder, side-scan sonar and Chirp sub-bottom profiler were used to map bathymetry, surficial sediments and sediment stratigraphy respectively. Side-scan sonar data, ground-truthed by surficial sediment sampling, yielded 3 distinct acoustic facies, interpreted as sand (90% of study area) bedrock (9%) and gravel (1%). Oblique nearshore sandwaves, (wavelength 20 - 60m, height 0.8 - 2.4m) are replaced 1.5km offshore by planar sands (20m water depth). Adjacent to the bedrock headland of Portstewart Point lies a relict shore platform (at −30m OD Belfast), likely formed during a late-Pleistocene lowstand. Individual boulders up to 1m diameter are imaged on the bedrock surface. The surface is partially overlain by active, shore parallel gravel wedges surfaced by ripple beds (wavelength 1.5m, height 1.0m) which are partially overlapped by planar sand. Repeat seasonal surveys show general onshore surface bedform migration during winter and offshore re-distribution of sediment in summer. These changes suggest that west to east tidal currents re-circulating sediment between the offshore and nearshore zones are modified seasonally by changes in wave regime and river discharge. Chirp surveys revealed two main seismic stratigraphic units, termed inshore and offshore, overlying the acoustic basement, the inshore unit being more internally complex. Four major controls on Holocene nearshore sedimentation on the north coast of Northern Ireland are suggested: (1) antecedent geological constraints, (2) sediment supply, (3) wave climate and (4) tidal current regime. Apart from antecedent geology, these controls have been, and continue to be, modified by RSL fluctuations and storm events.

A preliminary scanning electron microscope study of honeycomb weathering of sandstone in a coastal environment

AbstractHoneycomb weathering has been observed in a Carboniferous sandstone at a coastal location near Ballycastle on the north coast of Northern Ireland. Specimens of this sandstone have been analysed by X‐ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Results reveal that calcium sulphate (gypsum) is the only salt present and is found only at and immediately below the rock surface. SEM observations suggest that crystallization of salts in pores could easily dislodge quartz grains to promote granular disintegration, whilst etching of quartz grain surfaces attests to chemical weathering activity within the rock However, the reason for the development of the honeycomb pattern is not known.