I QUA Newsletter April 20QSj IQUA Cumann Re Cheathartha na h-Eireann Irish Quaternary Association http://www.tcd.ie/Geography/IQUA/lndex.htm April 2005 NS 34 ISSN 0790-4096
Editor: Catherine Dalton
1. Introduction A smaller audience was in attendance for the Spring Meeting and AGM 2005. Fraser Mitchell questioned how we could make the Spring Dear All, meeting more popular, especially among young researchers and postgraduates. It was I became a member of the RIA Geography suggested that the meeting next year be led by committee in November 2004 and now have postgraduates. additionally been co-opted as a member of the RIA Geosciences committee. I hope to represent the The treasurer’s report reflected the successful interests of IQUA on both committees. year. Lapsed members were encouraged to re subscribe and the corporate members were Catherine Dalton encouraged to pay two years in advance. The guide books sales are also well up on previous years. There are presently 85 paid members. 2. IQUA Fieldmeeting 2005 A suggestion was made to re-instate a prize for There will be no annual fieldmeeting this year, due the best postgraduate talk at the Spring meeting. to the QRA / IQUA fieldtrip April 5-9,h 2005. This will be discussed at the next committee meeting.
Proposals for the 2005 Autumn Symposium 3. IQUA Spring Meeting & AGM included ‘Reconstructing Changing Climates’. 2005 Susan Hegarty (UCD) and Freea Itzstein-Davey (TCD) have offered to organise the event. A The IQUA AGM took place on Saturday, March provisional date of 25th of November has been 12th, in the Museum building, TCD. In general, it suggested. was thought that IQUA had a successful year. Special thanks are due to Michael Philcox who IQUA Committee organised both the autumn symposium and the Both Pete Coxon (Chair) and Susan Hegarty spring meeting this year. (Secretary) have served their four-year term in office. Nominations were sought first for chair IQUA held a very successful joint fieldtrip with the Michael Philcox proposed Steve McCarron for IAH to North Mayo late last year (see NS 33). It was Chair. The nomination was seconded by Susan noted that this is the second year without a Hegarty. Steve was appointed Chair. fieldguide and it is hoped to redress this in the Nominations for secretary were subsequently coming years. looked for. Steve McCarron nominated Robin Edwards. Pete Coxon seconded. Robin was The autumn symposium “Atlantic Coastal and appointed secretary. Offshore Quaternary: Deposits, Sea-Level Changes and Archaeology” also went very well. There was The committee, as of the end of the AGM was: an excellent attendance for the second year in a Steve Me Carron (Chair) row, with 75 - 80 in the audience at any one time. Michael Philcox (Treasurer)
1 IQUA Newsletter April 2005
Robin Edwards (Secretary) northwards. The magnetic data indicates the Catherine Dalton (Newsletter editor) presence of an igneous body in the west which Paul Dunlop (Publicity officer) dips underneath the landward Carboniferous Tony Brooks (Postgrad representative) sediments. This body appears to outcrop in the Mike Simms far north west of the survey area. Its morphology Susan Hegarty and fracture patterns indicate it may be granitic.
AGM Abstracts Cainozoic development of the Proteaceae in south-western Australia Geophysical insights on the geomorphology Freea Itzstein-Davey and palaeo-landscape of the River Shannon at Geography Department, Trinity College, Dublin Clonmacnoise and offshore west of Kerry Head G. Duffy1, C. Brown1 and K Barton2 South-western Australia is a globally 1 Department of Earth and Ocean Sciences. NUI Galway significant hotspot of plant species diversity, with 2 Landscape Geophysical Services, James St Claremorris Co high endemism and many rare plant species. Mayo Proteaceae (Banksia family) is a major E-mail: gavm duffv@ nuictalway io component of the south-western Australian flora, though little is known about how its diversity 10 years ago the remains of a wooden developed. This prompted an integrated study to structure traversing the River Shannon at investigate changes in the abundance and Clonmacnoise was discovered by underwater diversity of Proteaceae, in south-western archaeologists. They have interpreted it as an Early Australia, by concurrently studying three Medieval bridge crossing dated at 800AD. This sediment sequences of different ages over the discovery led to a project to investigate the Cainozoic and a modern pollen rain study. usefulness of high resolution waterborne Modern pollen-vegetation relationships geophysics for the purposes of underwater in the two Proteaceae species rich nodes of the archaeology. The acoustic techniques of side scan northern and southern sandplains were sonar, swath sonar bathymetry and sub-bottom quantified. It was found that Proteaceous genera profiler (Chirp) were employed. The techniques can contribute up to 50% of the total pollen rain. have enabled the classification of river bed The vegetation and environmental setting during sediments. A profile of esker morphology and the three pivotal periods of the Cainozoic: Holocene, highly variable karst topography upon which it lies Pliocene and Eocene, were investigated. has been constructed. We have identified the Eocene sediment from Lake Lefroy presence of gas, possibly due to the decay of confirmed the presence of a Nothofagus organic material at depths < 10m. dominated rainforest in the Middle to Late The detailed bathymetry map identifies the Eocene. At this time Proteaceae species were at current regime in the Shannon today and goes least as diverse as today, if not more so, some way to explaining the differential preservation contributing up to a maximum of 42% of the total of the wooden post remains. Presented is a pollen rain. This study also identified that possible explanation as to why there appears to be Proteaceae species representation varies across 'missing' posts in the middle of the river. A palaeo- landscape reconstruction using detailed seismic and small lateral distances. Thus as samples varied spatially and temporally, single core samples are bathymetric information suggests that the posts may not sufficient to identify spatial patterns in never have been there in the first place. The Proteaceae or other low pollen producing taxa. analysis of fluvial processes has implications for Some 7.91 cm of laminated Pliocene recognising where the archaeological record has sediment from Yallalie, south-western Australia, been preserved and where it has been destroyed. was also examined. It covers 84 years of record In May 2004, the GSI mapped roughly and confirmed other regional reports that south 1200sq km off the Shannon Estuary as part of it western Australia was covered by a rich Irish National Seabed Survey programme. The vegetation mosaic consisting of heathy and wet bathymetry data shows the location of palaeo- rainforest elements. Although Proteaceae coastlines and bedrock features that could only species were a consistent component of the have been sculpted by fluvial features. There is an pollen counts, diversity and abundance obvious lack of surface sediment despite the fact (maximum of 5%) was low throughout the that this area lies offshore from Irelands largest studied section. sediment carrying river, indicating perhaps that A 2 m core was retrieved from Two Mile strong northerly currents carry sediment Lake, near the Stirling Ranges, provided an early Holocene vegetation history. Geochemical and On the beach reworked sandstone palynological evidence recorded little change, boulders partly cover an organic mud >1 m thick. suggesting the environment of deposition was This may have been deposited in a marsh relatively uniform. Proteaceae species were noted behind a former storm beach on the edge of the throughout the core, though in low numbers, at a alluvial fan, a probable precursor of the extensive maximum of 3.5 % of the total pollen rain. existing back-barrier marsh. The organic mud is Findings of this research indicate that overlain by >60 cm of interlaminated fine, shelly Proteaceae species were an important and gravel, sand and mud, probably deposited at the consistent component of vegetation in south back of a sub-recent storm beach. western Australia over the Cainozoic. It is likely that Within the mountains the steep-sided both changing pollination mechanisms and changes Curraheen valley has been cut deeply into in associated vegetation are important in massive-bedded red sandstone of the Kilmurry determining the dispersal of Proteaceaous pollen. Formation (340 m thick: Pracht 1996). The upper By understanding how the vegetation has changed part of the cliffs consists of the sub-horizontal and developed in south-western Australia, present Lough Slat Conglomerate Formation, which has vegetation can be managed to include intra-specific a horseshoe-shaped outcrop around the valley. variation and ensure the majority of species are This is clearly the source of the abundant conserved for present and future generations to conglomerate blocks within and beyond the enjoy. valley, but no prominent scar, that might be linked with an abnormally catastrophic event, has yet been identified. The valley floor is crossed by a variety of The Curraheen Lobe, Slievemish - giant debris debris deposits, including small recessional flow or what? moraines and large blocky boulder ridges. Near Michael Philcox the head of the valley one such ridge, >12 m Geology Department. Trinity College. Dublin high, extends obliquely down valley from the steep rock wall on the north side, but terminates The Curraheen River flows north out of the before reaching the opposite cliff. It consists of Slievemish mountain front 4 mis SW of Tralee. It is large, clast-supported blocks of sandstone and here at the apex of a large fan-shaped sediment conglomerate, most of which have been body, termed the "Curraheen Lobe', which is c.1.5 transported well out from their initial km across (E-W), has a steep arcuate front some accumulation zone, possibly as prolonged 30-40 m high, and resembles from below a terminal rockfall onto moving ice. Up-valley from this moraine. However, behind the arcuate front the boulder ridge bedrock rises smoothly into the surface continues to rise, more gently and with a backwall, and there is no ice-deepened bowl corrugated form, to the apex. The surface is littered typical of corries. The various sediment bodies with angular blocks commonly >4 m across, within the valley appear to be younger than the composed of red sandstone and distinctive, quartz- Curraheen Lobe, as they could not have survived rich conglomerate. The few river-bank exposures its formation. (<5 m deep) show angular to edge-rounded, matrix- The Curraheen River system offers supported boulders within unsorted pebbly sand various avenues for future research into its long and silt. The deposit can probably be classified as a and complicated development. rock glacier, though its precise mode of formation is as yet unclear. Its composition resembles a till or Reference'. Pracht, M.. 1996. The geology of Dingle Bay: a debris flow. However, the overall morphology is not geological description to accompany the bedrock geology 1:100.000 map series. Sheet 20. Dingle Bay": Geological till-like, and the size of the deposit is large for a Survey of Ireland. debris flow. Matrix-support for the boulders is compatible with some types of rock glacier. At the foot of the Curraheen Lobe a quarry Glaciofluvial discharge regimes of the reveals coarse alluvial boulder gravel <5 m thick Pleistocene River Slaney Valley lying directly on Old Red Sandstone bedrock. The retrodiction and correlation with glaciomarine elevation and poor exposures of the top of the events gravel indicate that it underlies and predates the Elizabeth McNicholas and Colman Gallagher lobe. Outside the lobe similar gravel is locally Geography Department, University College. Dublin exposed in a large alluvial fan extending down to sea level 1 km away. The apex of this fan The Slaney Valley reflects high presumably coincides with that of the Curraheen glaciofluvial discharges regimes. Discrete Lobe, but it is not exposed process zones are reflected in distinct sets of landforms and correlated sediments within the Jrifei Hsrit sic -1 ft!t if 'i. p ! '-IT ' valley. This research aims to identify and characterise these process zones using both Ongoing projects in the Quaternary and sedimentological and topographic means. The Geotechnical section of the Geological process zones are indicative of dynamic ice margins Survey of Ireland and changing base levels, both isostatic and X. M. Pellicer, M. Sheehy eustatic, during Oxygen Isotope Stage 2. The Quaternary and Geotechnical Section, Geological Survey of purpose is to understand Pleistocene glacial Ireland. Dublin, Ireland activity, denudation of Irish landmass and the transport of sediment to the Irish Sea basin. The Quaternary and Geotechnical The research is based on the observation, Section of the Geological Survey of Ireland is recording and analysis of glacigenic landforms and currently working on several projects involving sediments. The landforms are to be used as Quaternary Geology mapping, the national surrogates in the interpretation and retrodiction of geotechnical database of site investigation palaeoprocesses. Valley morphology was initially reports and associated map outputs, as well as mapped from aerial photographs that provided the work of the Landslides Working Group estimates of palaeodischarge and maps for field Quaternary Geology mapping is work. In addition to this, a Digital Terrain Model will currently being carried out in areas of South be created from Ordnance Survey height data. County Westmeath, North County Offaly and Geotiff and ortho-photos, digitised Quaternary data. County Louth. This process involves compilation Lidar data and mapped morphology from the field. of existing data/literature, satellite image and Exposures will provide insight into the sedimentary aerial photography interpretation, fieldwork sources and provide data required in the (encompassing site description, drilling, palaeohydrological reconstructions. The sampling, and analysis) and compilation of combination of the two data sets should create a acquired data into final product. A by-product of coherent spatial model of the relationships between the quaternary mapping program is the forms, sediments and palaeoprocesses in the production of depth to bedrock maps for the Slaney Valley. areas under investigation. The use of So far. using a Trimble roving GPS. geostatistical analysis techniques is currently glaciofluvial terraces, kettle holes and existing being tested with a view to improving this exposures have been mapped and the exposures process. logged. This work has allowed the identification of The geotechnical borehole database three distinctive reaches, each comprising a distinct now has a total of 4395 Reports containing over glacigenic process zone. Reach one from Stratford 50.000 borehole/trial pit/probe logs. Of these to Baltinglass. is characterised by prolific erratics 3093 have been fully scanned into the GSI and well defined, high terraces. Reach two lies Document Management System (DMS). Data within the Tullow basin and is characterised by only input into the Oracle database has now reached one ill-defined glaciofluvial terrace and generally flat over 2600 reports containing over 31.000 land. Aghade Bridge to Bunclody is the last reach, borehole and trial pit logs. This digital database which is a deep forested gorge, where bedrock is will permit a more efficient and rapid access to close to the surface and erratics are located at high data. It is used extensively by consulting levels above the present river bed. Within reach engineers and geologists, it allows for the one. Saundersgrove and Manger pits support development of a variety of map products for major urban areas, such as depth to bedrock Farrington and Mitchell's (1973) ice limit in phase two. Preliminary cross sections, systematically contour maps. To date the location of over 8800 matched across valley from the DTM and field boreholes and trial pits in Dublin and other cities evidence, suggest maximum palaeodischarge of has been digitised. 22x103m3s 1. However, hydrologically relevant The GSI Landslide Working Group has longitudinal profiles and cross-sections will be developed a database of landslide events in estimated by plotting the thalweg depth from Ireland, now numbering just in excess of 100 discrete, representative cross-sections in each events. These are mostly developed in peat. process reach. Hence, key palaeochannel hydraulic The Group is also examining the geotechnical and channel-geometry variables are being parameters involved in slope failure. It is also measured and will be used. along with considering the feasibility of landslide sedimentology, to retrodict the key spatial elements susceptibility mapping in Ireland. A pilot project of the palaeodischarge regime of the glaciofluvial in the Breifne area, covering parts of Co. Cavan, Slaney. Leitrim and Sligo, is currently underway. An important part of the work is also to make ...... recommendations for the integration of the landslide issue into the planning process. cri: < m . f Wi'rrr------io -.ty is -to s It is not possible to reconstruct large Vegetation response to climate change in herbivore densities and so this hypothesis is Ireland and north-west Spain over the last 4500 tested by comparing relative proportions of years Quercus and Cory/us pollen from regions which Bettina Stefanini supported large herbivores with data from Botany Department Trinity College, Dublin Ireland, where large herbivores were excluded. stelanb'a tcd.ie Similarity between the two data sets indicates that large herbivores were not required to My research forms part of ACCROTELM, a maintain these taxa in the primeval landscape. three year project funded by the European Fine spatial resolution pollen data from Commission under the Fifth Framework small hollows in Europe and eastern USA Programme. ACCROTELM (Abrupt Climate provide another opportunity to explore the Changes Recorded Over The European Land hypothesis. Data from moss polsters show that Mass) aims to quantify the extent and timing of percentage arboreal pollen is a reliable indicator climate change events of the late Holocene. High of canopy openness in these sites. The resolution multi-proxy analysis of well dated peat palaeoecological data demonstrate that open cores are used to try and establish climate change canopy forest has only ever been maintained by events from eight sites across Europe. human exploitation Ten partner institutions are generating Large herbivores in Europe do not climate-proxy records through the analyses of therefore appear to have maintained an open humification, micro and macrofossil, testate landscape in primeval times although evidence amoebae and bimolecular data. The data will be suggests that they would have influenced the supported by detailed, wiggle-match dated species composition of the forest canopy. chronologies. My research project covers humification Relevant references: and microfossil analysis from the Irish and the Vera. F.W.M. (2000) Grazing ecology and forest history Spanish sites. In humification alkali extracted humic CABI. Wallingford. acids are assessed through colorimetry to try and Mitchell. F.J.G. (2005) How open were European primeval lorests? Hypothesis testing using palaeoecological data. establish the rate of decay of organic materials Journal of Ecology. 93. 168-177. within peat sediments. Microfossil analysis on the other hand focuses on changing patterns of pollen and other palynomorph deposition on mire surfaces through time. I am using it to reconstruct past The Characteristics of Ribbed Moraine and vegetation changes on a local through regional Assessment of Theories for Their Genesis scale. So far I have completed humification from Paul Dunlop both sites and am currently working on pollen The University of Ulster. Department of Environmental analysis. Sciences. Cromore Road. Coleraine. Northern Ireland BT52 1SA.
Ribbed (Rogen) moraines are large subglacially formed transverse ridges that cover The application of palaeoflower arranging to test extensive areas of the beds of the former palaeograzing hypotheses Laurentide. Fennoscandian and Irish ice sheets. Fraser J.G. Mitchell Botany Department. Trinity College Dublin Since the flow speeds and stability of ice sheets are known to be sensitive to conditions operating Frans Vera has proposed a hypothesis that at the bed. a full understanding of the processes large herbivores maintained an open parkland type of ribbed moraine genesis are critical if we are to landscape in primeval times across lowland Europe. appreciate their role in ice sheet dynamics. This hypothesis relies primarily on the interpretation Numerous hypotheses exist that seek to explain of European pollen data which are dominated by how ribbed moraine are formed: by shearing and high abundances of Quercus (oak) and Corylus stacking of subglacial sediments (e.g. Aylsworth (hazel). These trees cannot regenerate under dense and Shilts. 1989: Bouchard. 1989): as a shade and so their abundance is assumed to consequence of subglacial megafloods (Fisher indicate a more a more open landscape that was and Shaw. 1992): by fracturing and extension of maintained by large herbivores. If natural forest frozen till sheets (Hattestrand. 1997) or by landscapes were indeed more open current forest sediment deformation (Boulton. 1987: conservation management policy across Europe Hindmarsh. 1998a.b. 1999). However, given that would need to be reconsidered. their formation has never been observed, advances in knowledge have to rely on abduction. That is. hypotheses, theories or models Archaeology". Until the recent mapping of the are generated that seek to best explain their seabed by the Irish National Seabed Survey characteristics (pattern, size, shape, internal (INSS). very little was known about Ireland's composition etc). The most successful hypothesis Atlantic coastal and offshore region. However, will be the one that provides the most complete the work of the INSS allied with recent advances explanation of ribbed moraine characteristics. This in {inter alia) digital bathymetric mapping and sub approach is problematic given that ribbed moraine bottom profiling has facilitated increased characteristics are poorly known. Scrutiny of the research in this area. Indeed, this topic is now at literature reveals that detailed observations are the forefront of Irish Quaternary studies and this limited to small areas (normally < 1500 km2) and was reflected by a good attendance at the with small sample sizes (i.e. probably <50 ridges). symposium by both speakers and audience Generalisations drawn from this base cannot be alike. Encouragingly, there was a strong regarded as being representative and thus remain postgraduate contingent, with representatives an inadequate data source for testing the various from Trinity. NUI and QUB discussing their hypotheses. This paper addresses this deficit by ongoing research. producing the first representative data set on ribbed moraine characteristics. The conference was opened by Michael Various remote sensing and GIS Geoghegan who discussed the current state of techniques were used to record the morphological, play with regards the work carried out by the morphometric and spatial characteristics of ribbed INSS and the importance of this new bathymetric moraines in Ireland, Canada and Sweden, over a data to our understanding of the Quaternary in combined area of 81.000 km2. This database of this region was aptly demonstrated through the 36.000 individually mapped landforms demonstrates talk that followed by David Hardy. The ensuing that many published accounts are somewhat talks by Julian Carolan and Barbara Gylnn misleading and unrepresentative, and that ribbed delivered case specific examples from Clew Bay moraine morphology is more complex than was with a focus on the late Quaternary glacial hitherto reported. For example it is shown that history and the geomorphological processes that ribbed moraines often form independent of have shaped the bathymetry of the Bay. The topographic influences, are not always curved afternoon session had a heavy bias towards sea- down-ice. do not have accordant summits, can have level research with Melissa Harmon. Michael both steep proximal and distal sides, have O'Connell. Joe Kelley, Tony Brooks and Joseph undulating crests and resemble waves, are not P. Kelly presenting evidence for late Devensian always anastomosing and do not necessarily fit and Holocene relative sea-level change from neatly together like a jigsaw. Our database of ribbed both the north and west coast. In addition. moraine ridge length, width, height and wavelength Michael Gibbons' discussion on the inter-tidal is also presented and reveals they exist over a landscapes of Mayo and Galway added an much larger scale range than was previously archaeological dimension to the symposium thought. These new data were used to test the whilst Peter Haughton (on behalf of Lena various ribbed moraine theories. This led to the Ovrebo) concluded the presentations with a rejection of the topographic model of shear and discussion on offshore Quaternary deposits stack and undermined the credibility of all other along the margins of the Rockall Trough off shear and stack hypotheses, the two-step western Ireland. hypothesis, the megaflood hypothesis and the thermal fracturing model of formation. Given that Anthony Brooks. Geography Department. TCD. ribbed formation is not due to localised factors such as topography and on the basis that their patterns Full abstracts for all the 2004 symposium are repetitive, organised into dominant wavelength presentations are below: and are widespread it is strongly argued they are most likely the product of an instability mechanism 2004 Symposium Abstracts] that operates in the subglacial environment. An Overview of the Irish National Seabed Survey. highlighting Recent-Quaternary 4. IQUA Autumn Symposium features. Michael Geoghegan and Eibhlin Doyle The annual symposium for 2004 was held on the In 1999 the Government allocated '-< P ' 26lh November at the Geological Survey of Ireland over a seven-year period to fund the mapping of and focused on the "Atlantic Coastal and Offshore Quaternary: Deposits. Sea-Level Changes and lielands designated waters. The management
! . J i .1. Ji.-i Irish National Seabed Survey - coverage by 1st October 2004 vessel Celtic Voyager, working on behalf of the GSI, collected a range of acoustic and geophysical datasets. The survey was primarily focused on the collection of Multibeam Echosounder data, however, 3.5kHz sub-bottom profiles and magnetic data were also collected for each line. In addition, some 60 bottom- samples were retrieved using a Van Veen grab. The initial focus of this project was related to the possible existence of Tertiary channels in the area, however, the datasets available are more suited to a study of the Quaternary geology of the region. The main techniques used are multibeam Preliminary interpretation of the echo sounding, single beam echo sounding, bathymetry and acoustic backscatter data (EM120 and 1002), sub bottom profiling, gravity and identifies an inner and outer "basin'\ separated magnetics. Side scan sonar and high resolution by a large North-South trending moraine (some seismics have also been used for specific studies. 26 kilometres long, with an associated In addition preliminary groundtruthing has been topographic height of ~25m). Several moraines carried out and airborne laser techniques have been of lesser dimensions can also be recognised. To used in shallow water areas where the water clarity the southwest of the area surveyed, significant is good. exposures of bedrock occur, and a potential The results of this project have been far exists for correlation with the mapped onshore reaching, serving various sectors such as oil and geology. gas exploration. marine aggregate, fishing, A working shallow stratigraphy for the engineering, environmental and research. area has been developed[1], and approximate A number of important features, related to sediment isopach and palaeotopography glaciation, have been recognised, some of which surfaces generated based on the 3.5kHz Profiler are the subject of current research. On the Rockall data. and Porcupine banks iceberg scour marks and Ongoing work aims to produce seabed pockmark have been observed. Closer to shore classification maps. based on statistical glacial moraines have been identified. Submarine backscatter analysis (see [2] for a description of slides have been identified, e.g one which originates the methods and technologies on which this off the Rockall Bank and flows into the Rockall based), in conjunction with the integration of all Trough and measuring 100km wide by 150km long. available datasets in a GIS environment. The age of this slide is unknown but examination of Planned future work aims to correlate the its features would indicate a recent age. It may be morphology and sedimentology observed, with Holocene in age similar to other such slides in UK data reported from onshore, in order to link the and Norwegian waters. More recent features area with the "greater-picture" and potentially include major sand waves related to the currents at provide some dating constraints for the features work at present and the growth of the deep cold- observed. water corals. The talk will illustrate many of these [1] Marine Institute .• Geolab End of Leg Report for Donegal features and the techniques used to identify them. Bay 2002 [GSI internal report). [2] Preston. J.M. et al (2003t Sedimenl Classification Based ) on Repetitive Bathymetry Surveys of an Offshore Disposal Site, during the post-glacial sea-level rise. Integration IEEE Oceans 03. 69-75. of the bathymetric and sub-bottom data allows Acknowledgements Data and funding for project provided by GSI. the relationship between seafloor topography Supervision by Dr. John Graham (TCD). Michael Geoghegan and the underlying strata to be investigated. Data (GSI) and Dr. Eibhlin Doyle (GSI). were integrated on a GIS platform where they can be successfully queried, visualised and l_ . ■ , -y ' . V f ^ # '■ , ■ , manipulated spatially to reveal previously unknown relationships. The use of GIS permits the use of fragmentary geomorphological and f -’; v 5 v geological evidence to allow a new approach to ;•* : .C the reconstructing of Late Quaternary ~ ■- ■ . • . environments. Clew Bay can be sub-divided into eleven bathymetric units based on average water depths and geographic location. Three first-order Acoustic Facies Units (AFU-1. -2 & -3) and two second order units (AFU-2(B), -2(C)) are identified within the subsurface, which correlate with the surficial units SU-1, SU-2 & SU-3. Sedimentary facies within the system consist Fig. 1. 3D image of large moraine feature surveyed and predominantly, of redistributed glacigenic associated ~outwash plain ". Image oriented to the North. deposits. Basement rock exposures being common throughout the study area while local trends in sediment thickness are strongly related to antecedent topography. Major submarine features of interest imaged within the study area include: two geographically distinct hummocky • -X * moraines, the smaller within the inner bay. and a ____* second large composite multi-lobate. east-west trending series of ridges in the outer bay. A series of oval-shaped, bathymetric highs are § g a g ■. identified as erosional remnants of drumlin ’«4- ' ■? • forms, in various stages of preservation, which divide the inner bay into two major areas based on the dominant surficial and subsurface sedimentary units. The outlines of lag seafloor Fig. 2. Hillshade derived Irom Multibeam bathymetry, showing footprints have a distinct east west long axis rock outcrops surveyed to the southwest of area and associated trend. This trend is similar to the preferred onshore geology (from GSI 100K Bedrock Series). orientation of the long axes of drumlins in the Clew Bay area and indicates the dominant flow direction of the Late Midlandian ice sheet. Modifications of the drumlins occurred during two Reconstructing the Late Quaternary evolution of distinct periods: 1. Ice re-advance, and 2. marine Clew Bay: A journey through digital bathymetry. transgression. Drumlin orientation and 'Chirp’ sub-bottom profiling, Laser Airborne morphometry suggest a statistically significant Depth Sounding (LADS) and computer mapping. phase of secondary overprinting of these units Julian Carolan with length- breadth ratios increasing toward the Department of Geography. Queens University Belfast, e-mail: i.carolan 'g oub.ac.uk ice proximal end of the glacial depositional system. The results of this study indicate that The seafloor and subsurface shallow shelf relative sea-level changes in conjunction with environments within the formerly glaciated, local geological control had a profound effect on bathymetrically complex. Clew Bay were mapped the deposition, erosion and preservation of using a combination of: digital bathymetry. 235km of sediment on the shelf of the inner bay throughout high-resolution (2-10kHz. 4 pulses/second) FM the Late Quaternary and that the shallow Chirp' sub-bottom reflection profiles and 175kma of subsurface greatly influences many aspects of Laser Airborne Depth Soundings (LADS). Key the present surficial morphology. objectives of the study are: (1) to better understand the sedimentary processes, and (2) to reconstruct Suggested reading: Eyles. N.. Boyce. J.I.. Halfman. J.D. & Koseglu. B.. 2000 coastal/geomorphological evolution of the bay Seismic stratigraphy of Waterton Lake, a sediment- staged glaciated basin in the Rocky Mountains of Alberta. describing the distribution of sediment on the Canada and Montana, USA. Sedimentary Geology. 130. seabed. The analysis minimises subjective and 283-311. Hewitt, A.T. & Mosher, D.C.. 2001. Late Quaternary stratigraphy qualitative interpretations of the acoustic images. and seafloor geology of eastern Juan de Fuca Strait. British The geology reflects Clew Bay’s Columbia and Washington. Marine Geology, 177. 295-16. extensive glacial history and until now, certain Knebel. H.J. & Pope, L.J., 2000. Sea-floor environments within glacial erosion and depositional features in the Long Island Sound: A regional overview. Journal ol Coastal Research, 16(3). 533-550. area were unmapped. A terminal moraine Locker. S.D., Albert. C.H. & Brooks. G.R.. 2003. Regional marking major ice limits during the Last stratigraphic framework linking continental shelf and coastal Glaciation (Midlandian) is present as described sedimentary deposits of west-central Florida. Marine onshore by McCabe and Clarke 2003. Other Geology, 200. 351-378. Todd. B.J., Fader, G.B.J., Courtney, R.C. & Pickrill, R.A., 1999. features include submerged drumlins. submarine Quaternaty geology and surficial sediment processes. glacial erosion channels. Clare Island's Browns Bank. Scotian Shelf, based on multibeam palaeocoastline, the extension of highly faulted bathymetry. Marine Geology. 162. 165-214. rock units offshore and major geological contacts. The sediments in the area have been sampled and corroborate interpretation of the backscatter. What shaped the seabed? Seabed processes off the north coast of Clare Island, Clew Bay. Batco. C.R. & Byham, P.W.. 2001. Bathymetric Sidoscan Barbara Glynn. Colin Brown and Shane Rooney. Techniques for Near Shore Surveying. The Department of Earth and Ocean Sciences. National University of Hydrographic Journal. No. 100 April 2001. pp. 13- Ireland. Galway. 18 McCabe. A.M. & Clark, P.U. 2003. Deglacial chronology from Marine geologists have over the last County Donegal, Ireland: implications for deglaciation of the British-lrish ice sheet. Journal of number of years become increasingly involved in the Geological Society. London. Vol. 160. pp. 847- the application of acoustic remote sensing in 855. offshore geological mapping. This is a direct result Parsons et al.. 2004. Feasibility study on the establishment of of significant advances in the resolution and a large scale inshore resource mapping project. A report to the Marine Institute. Reference: accuracy of seabed mapping technologies, primarily DK/01/007. (In Press). swath acoustic systems and an improved Pratson. L.F. & Edwards. M.H.. 1996. Introduction to understanding of complex seabed processes advances in seafloor mapping using sidescan (Pratson & Edwards 1996. Todd et al. 1999, Bates sonar and multibeam bathymetry data. Marine Geophysical Researches. Vol. 18. pp. 601-605. & Byham 2001). Mapping the inshore zone has Todd et al.. 1999. Quaternary geology and surficial sediment many additional important applications e.g.. processes. Browns Bank. Scotian Shelf, based on bathymetry as an aid to navigation; the identification multibeam bathymetry. Marine Geology 162. No.1 of seabed bottom type: siting of offshore pp. 165-214. engineering developments; location of potentially economic sand and gravel deposits; pipeline and cable locations: environmental habitat studies: Relative Sea-Level Observations and Their underwater archaeological studies and many more Implications for Glacial Rebound Modelling in (Parsons et al 2004). Ireland Swath bathymetry and backscatter data Anthony Brooks have been collected simultaneously using Trinity College. Dublin interferometric sonar over an area of 37 km2 in Clew Bay. The sonar is a phase discrimination system, All records of Irish Sea level since the operating at a centre frequency of 234 kHz. It has a Last Glacial Maximum (LGM) reflect the interplay maximum swath width of 300 m and can give 100% of both glacio-isostatic and eustatic components. seabed coverage in waters up to 100 m in depth. This isostatic signature is derived from the The bathymetric resolution can be as good as 0.075 lithospheric response to local, regional and extra- m. A high-resolution bathymetric map of the area regional ice cover but most significantly, the has been created for interpretation in terms of location of the Irish land mass near the periphery geological processes and has been integrated into a of the former British Ice Sheet margin meant Digital Terrain Model. Backscatter is a measure of spatial variation in ice loading thus substantial strength of the echo returned from an object or differences in glacio-isostatic adjustment (GIA) patch of seabed. Bathymetry and backscatter have histories: In the North of the region fluctuations been used to characterise the seabed geology and in the strength of the eustatic signal lelative to can be correlated with the onshore geology. A isostatic uplift since the LGM has led to highly statistical analysis of backscatter amplitude has non-monotonic curves of Late Deven lan and allowed for the generation of an acoustic facies map Holocene relative sea level (RSL) (e g Lanbeck. 1996: Carter. 1982): Conversely in the South, the and 2: The adoption of a calendar year dominance of the eustatic signal over that of the chronology (based on the calibration of isostatic component since the end of the Late radiocarbon dates) in preference to a 14C Glacial up until the Late Holocene has imparted a chronology to circumvent problems linked with a dominant positive sea level tendency on RSL posteriori correction (Peltier et al.. 2002). curves from the region (e.g. Lambeck. 1996, In the past decade, significant findings in Sinnott, 1999). the field have delivered new constraints on the In addition to providing valuable information timing and magnitude of late Devensian ice build in their own right. RSL data are powerful tools in the up and decay: The work of Bowen et al.. (2002) wider study of glaciation, climate change and Earth has delivered a suite of cosmogenic dates which structure. Their intimate link with GIA and eustatic provide much firmer chronological control on the sea level means that they contain within them evolution of Devensian ice cover whilst the work information regarding former ice extent, thickness of McCabe et al.. (1998): McCabe and Clark. and melting history, as well as data pertaining to the (1998) and McCabe. (1996) has significantly physical structure of the Earth and its response to augmented our knowledge of ice sheet evolution loading. This information can be distilled through subsequent to the LGM. Furthermore, sea level the combination of RSL data and geophysical data delivered by Sinnott. (1999). Devoy et al.. modelling. Importantly, the location of Ireland (2004) and Cooper et al.. (2002) has significantly beyond the margins of the main accumulations of improved our understanding of patterns of GIA Wu'rm-Wisconsin-Devensian ice sheets, mark it which are directly linked with former crustal out as an especially sensitive area for such loading. The above suggests that now is a fitting modelling attempts. time to consider a new ice model for Ireland in The general theory pertaining to the the light of these more recent advances. application of geophysical models for the prediction of RSL change, and their validation via the use of Bo’.ven. D.Q.. Phillips. F.M.. McCabe. A.M.. Knutz. P.C and radiocarbon-dated Sea-level Index Points (SLI’s) is Sykes. G.A. 2002. New data for the Last Glacial Maximum in Great Britain and Ireland. Q uaternary presented in Lambeck (1996) and Peltier et at. Science Reviews. 21. 89-101. (2002). In brief, the modelling approach involves Carter. R.W.G. 1982a Sea-level changes in Northern the combination of an ice model predicting the Ireland. Proc. of the Geologists' Association. London. thickness, distribution and melting history of 93. 7-23. Cooper. J.A.G.. Kelley. J.T.. D.F.Belknap. Quinn. R and terrestrial ice. and an earth model predicting the McKenna. J. 2002. Inner shelf seismic stratigraphy off Earth's deformation under varying loads of ice and the North coast of Northern Ireland: New data on the meltwater. In the past, several attempts at glacial depth of the Holocene low stand. Marine Geology 186 369-387. rebound modelling have been made for Ireland. The DeLaughter J.. Stein. S. & Stein. C.A.. 1999 Extraction of a most notable of these are the efforts of Lambeck. lithospheric cooling signal from oceanv.ide geoid data. (1996) and Lambeck and Purcell. (2001) although Earth planet. Sci. Lett.. 174. 173-181. significantly, their ice model estimates are Devoy. R.J.N.. Nichol. S.L. and Sinnott. A M. 2004 Holocene sea-level and sedimentary changes on the south coast conditioned by an earth model which is said to be of Ireland. Journal of Coastal Research. 39 inconsistent with the high quality RSL data from the Lambeck. K. 1996. Glaciation and sea level change for UK (Shennan et a!., 2002: Peltier et al.. 2002: Ireland and the Irish Sea since Late Peltier. 1998). The most recent ice model estimates Devensian Midlandian time. Journal of the Geological Society. London 153. 853-872. for Ireland can be found in the modelling attempts of Lambeck. K and Purcell. A.P. 2001. Sea-level change in the Shennan et al.. (2002) although whilst this can be Irish Sea since the Last Glacial Maximum: constraints seen as the most up to date and accurate estimate from isostatic modelling. Journal of Quaternary Science. of ice cover over Britain, the reluctance of the 16(5). 497-506. McCabe. A.M.. 1996. Dating and rhythmicity Irom the last authors to employ any of the Irish RSL data calls deglacial cycle in the British Isles. Journal of the into question the validity of their inferred ice sheet Geological Society (. London) 153. 499-502. topography: (Indeed, preliminary model runs McCabe. A.M. and Clark. P.U. t998. Ice seet variability suggest an increase in ice thickness is required, at around the circum-North Atlantic Ocean during the last deglaciation. Nature. 392. 373-377. least over the north of the country.) McCabe. M.. Knight. J. & McCarron. S. 1998. Evidence for The model employed in this investigation is Heinrich 1 in the British Isles. Journal of Quaternary based upon the same methods employed by Peltier Science. 13(6) 549-568. et al. (2002) and is used in preference to the model Peltier. W.R. 1998. Postglacial variations in the level of the sea: implications for climate dynamics and solid-earth previously employed by Lambeck (1996) in Ireland. geophysics. Review of Geo physics 36. 603-89 Principal differences are 1: The use of a 90 km Peltier. W.R.. Shennan. I.. Drummond. R.. and Horton. B.P. lithospheric thickness (as opposed to 65 km) in 2002. Global to local scale parameters determining RSL accordance with recent geophysical and modelling changes and the post-glacial isoslatic adjustment of Great Britain. Quaternary Science Reviews. 21. 397- data (DeLaughter et al.. 1999: Peltier et al.. 2002) 408. T13— . : ■ u* * . . i m s. v « . r L . : 1 a r t *!• r I t - . •. . . i Sinnott, A. 1999. Holocene Sea-Level Changes From the South assemblages. Chronologies are provided by 14C and Southeast Coasts of Ireland. Unpublished PhD Thesis. dating accompanied by 10Pb and 137Cs analysis University College Cork, NUIC. for recent records. Surface analysis at Maas and Late Holocene Relative Sea-Level Changes core assemblages from Maas and Strath's Farm Recorded in County Donegal Saltmarshes: are described and discussed, with a Initial Results consideration of the benefits and difficulties of Melissa Harman using the saltmarsh microfossil record of RSL in School of Geography, Queen's University, Belfast. BT9 6DN, U.K Ireland. For example, the specific difficulties of [email protected] poor fossil foraminifera preservation at both sites and the linkage between the stratigraphic record Late Holocene relative sea-level (RSL) and microfossil assemblages are considered and change remains predominantly unknown across RSL changes on the millennial scale at Maas are Ulster, yet this is perhaps the most important time described. for making predictions regarding the direction and speed of future RSL. Although tide gauge records can be used to indicate RSL changes in the last century, the period previous to this remains Sea-level change in Galway Bay during the unknown The north of Ireland is a key area for later Holocene studying this period of RSL change, due to the dual Michael O'Connell impacts of the Scottish and Irish ice sheets and Palaeoenvironmental Research Unit. Department of Botany. resultant isostatic and eustatic effects following the NUI. Galway www.nuioalwav.ie/Dru melting of these ice masses. An east-west variation in RSL is expected as areas closer to the centre of Most of the investigations carried out to the Scottish Ice Sheet experience a greater isostatic date on Holocene sea-level change in Irish uplift following the melting of this ice mass, over coastal areas have centred on the northern and riding a rise in eustasy to create an net RSL fall, southern coasts with relatively few studies in the whereas those areas further west are likely to mid-western part of the coastal line. The relative exhibit an overall RSL rise. However, this trend is neglect of the mid-western coast is surprising likely to decrease over the length of the Holocene given it location between two areas with as the rate of isostatic uplift decreases. A PhD contrasting Holocene sea-level histories. This research project attempting to reconstruct RSL part of the coastline has also many favourable variation for this important period of approximately opportunities, in the form of partially submerged the last 2000 to 3000 years includes two saltmarsh peats and fossil timbers, for such investigations. sites from County Donegal: Strath's Farm, near In this paper, results of palaeoecological Malin. and Maas, near Ardara. investigations (1JC dating, pollen, Saltmarshes have proven to hold a high- dendrochonology. wood identifications, etc.) resolution record of RSL change in research based carried out at various times over the past several in both North America and Great Britain, through the years on coastal peats and fossil timbers on the study of microfossils preserved in their sediment northern shore of Galway Bay, between Salthill with attached chronologies. The location of and Barna, will be presented. Information saltmarshes at the land-sea interface is ideal for gleaned from multidisciplinary investigations of recording RSL change and the low-energy sediments taken from the present-day brackish environment of this bio-zone promotes the lake. An Loch Mor, on Inis Oirr. will also be preservation of microfossils. However, this source considered (cf. TIMECHS project). On the basis of data has not yet been exploited in Ulster and is of these investigations, relative sea-level utilised here as a first attempt at reconstructing the movements in the late Holocene for the Galway geologically recent RSL record to expand the Bay area will be reconstructed. knowledge of the RSL history of Ulster. Both foraminifera and diatoms are studied to create a multi-proxy record, with contemporary (surface) assemblages determined and compared The Exotic World of the Western Shore: Dog to various environmental variables (pH. conductivity, Whelk. Stone Boats and Barking Pans. loss on ignition/Carbon content, particle size Observations on the Emerging analysis, vegetation type and cover, altitude and Archaeological Landscape in the Inter-tidal tidal influence) in order to create a modern dataset Zone with special reference to the Galway from which transfer functions from the local to the and Mayo Coasts. legional scale can be developed. These transfer functions are then applied to fossil (core) Michael Gibbons reflectors earlier interpreted as peat to be gravel Member of the Archaeological Committee of the Heritage Council similar to coarse deposits which occur on the Member of the Institute of Irish Archaeologists. modern beaches. The 4 cores from Belfast Lough penetrated up to 2.5 m of red glacial- The recent discovery of eroding field walls marine clay overlain by shell-rich, muddy sand. in the intertidal peat at the northern end of Inishkea The contact between the clays and muddy sands North highlights once again the archaeological is abrupt and marked by up to 5 cm of sand and potential of this environment for settlement studies. rip-up clasts of clay in the overlying unit. We The recognition of landscape features, as distinct interpret this as a low-energy beach sand from individual monuments, is, however, nothing overlain by a tidal flat deposit that grades into new. A large intertidal-zone field system was first deeper subtidal materials. On the basis of these mapped on Tra Mor, Aran, in the Middle of the 19lh cores it appears that the lowstand did occur century. around "30 m depth. Radiocarbon dates have not In the past decade Ireland has jumped from yet returned on shells from the inferred beach quite a low base in this field to a pre-eminent and overlying material. position with award winning and pioneering studies of both Strangford Lough and the Shannon Estuary. An initial trawl through the published material together with a limited field survey programme has Temporal and spatial variations in Late highlighted the huge wealth of sites and monuments Quaternary slope sedimentation along the throughout this zone on the West Connacht Coast margins of the Rockall Trough, offshore at a time when it is undergoing unprecedented western Ireland. change. The sites and monuments being identified Ovrebo. L.K.. Haughton, P.D.W. & Shannon. fall into a number of categories, ranging from P.M. settlement and ritual/mythical through to military, Department of Geology. University College Dublin. Belfield. industrial and communications related remains. Dublin 4. Ireland. The Rockall Trough, offshore western Ireland, is a 1000 km long, 250 km wide, NNE- Sea-level lowstand off Northern Ireland: new SSW trending bathymetric depression with water cores and seismic reflection data depths ranging from 300 to >3000 m. The trough Joseph P. Kellyl. Andrew Cooper2. Derek is underlain by the Rockall Basin, which formed Jackson2. and Daniel Belknapl as a consequence of protracted Late Palaeozoic 1 University of Maine, Department of Earth Sciences to early Cenozoic continental rifting. In the Early Orono. ME 04469-5370 Neogene, deep-water circulation and drift 2 University of Ulster. School of the Environment. Coastal Studies Group Coleraine. Northern Ireland sedimentation was initiated. Late Neogene to Quaternary deposition on the slopes flanking the Although numerical models have estimated trough was controlled by climatic changes and the depth of the late Quaternary sea-level lowstand sea-level fluctuations that accompanied the off Northern Ireland at around -10 m. there are few onset of Antarctic glaciation. Previous work has or no data to support this. We earlier reported on focused on the Feni Drift along the west margin seismic reflection profiles seaward of beaches near and the NE Rockall Trough (north of 56SN) and Port Rush that suggested a lowstand around '30 m has shown that bottom current activity combined based on shoreline notches in rock and till and the with downslope remobilisation were the main stratigraphy shallower than '30 m. We interpreted a depositional processes (e.g. Armishaw et al., Quaternary section of glacial-marine mud over till 2000: Howe et al., 1994: Kidd & Hill, 1986: and rock. This was overlain by sand with several Stoker, 1997). Little work has. however, been prominent reflectors we speculated might be peat undertaken on the eastern margin south of 56eN deposits. In Belfast Lough seismic reflection data and it is therefore the focus of the present study. depict an acoustically transparent unit resting A total of 63 gravity cores have been unconformably over glacial-marine mud out to the studied from four sites along both margins of the ‘30 m isobath. Rockall Trough: i) the West Porcupine Bank at In the summer of 2004 we collected 13 the southeast entrance to the trough (52 - 539N): underwater vibracores in these areas to confirm our ii) the North Porcupine Bank (-54°): iii) the East earlier interpretations. The cores from the sandy Rockall Trough along the Erris High(~55925 N): shorefaces were short. Only one core encountered and iv) theWest Rockall Trough slope (~569N). the inferred peat reflector, and it contained coarse The core data have been integrated with high- gravel. All other cores contained massive fine sand, resolution bathymetry data, side scan imagery up to 1.6 m thick. On this basis we consider the and shallow seismic, allowing the study of DSEHM Stter Aprl2005 temporal and spatial variations in slope a wooden structure traversing the Shannon at sedimentation. This has allowed the creation of a Clonmacnoise. This was interpreted by series of 3D stratigraphic models that distinguish archaeologists as an Early Medieval bridge between local and regional controls on the crossing, dating from 800AD. This discovery led sedimentation at different points on the slope. The to a project to investigate the usefulness of high Porcupine Bank slope is particularly instructive as it resolution waterborne geophysics for the has a section of stable slope where the late purposes of underwater archaeology. The Quaternary succession can be traced across an acoustic techniques of side scan sonar, swath area of 1500 km2. The cores penetrate deposits sonar bathymetry and sub-bottom profiler (Chirp) revealing possibly up to 500 kyr of deposition, with were employed as well as a magnetometer for an alternation nf hnttnm r'lirront rownrkor) planlctnni/' m ntal H atarfinn T h e for>hr*irji io c had moclorcvto oozes and siliciclastic muds and sandy muds with success as artifact finders e.g. being capable of ice-rafted debris. Fades variations across the slope identifying some of the previously discovered log demonstrate both regional changes in current boats, but the vertical orientation and negligible strength leading to extensive erosion surfaces acoustic impedance of the water laden wooden (associated with climatic oscillations). and posts prevented their detection by any of the enhancements and decelerations of bottom currents techniques. It has been possible to classify the linked to local seabed topography (e.g. slope river bed sediments by combining all the acoustic gradient, canyons and carbonate mounds). data. A profile of esker morphology and the Cores from the other study areas recover highly variable karst topography upon which it only last glacial to Holocene stratigraphy. These lies has been constructed. sites can be compared and contrasted with the west The detailed acoustic bathymetry map Porcupine Bank. This comparison showed that the identifies the current regime in the Shannon margins of the Rockall Trough failed repeatedly today and goes some way to explaining the during the last glacial when bottom current activity differential preservation of the wooden post was subdued, whereas during the Holocene the remains. We have also identified the presence slopes were more stable and along-slope bottom of localised gas. possibly due to the decay of currents were the dominating margin shaping organic material at depths < 10m. This affects process. the strength of the sediments around the posts and may also have influenced their preservation. Amiishaw, J.E., Holmes. R.W. & Stow. D.A.V. 2000: The Barra Archaeologists have been puzzled by a 20m gap Fan: A bottom-current reworked, glacially-fed submarine tan system. Marine and Petroleum Geology. 17. 219-238. in the posts traversing the river and have Howe. J.A.. Stoker. M.S. & Stow. D.A.V. 1994: Late Cenozoic assumed that some 3 pairs of posts have been drift complex, northeast Rockall Trough. North Atlantic. removed by passing boat traffic despite the lack Paleoceanography. 9. 989-999. of evidence of their remains elsewhere on the Kidd. R.B. & Hill. P R. 1986: Sedimentation on mid-ocean drifts. In C.P. Summerhayes and N.J. Shackleton (eds): North riverbed. With the aid of detailed seismic and Atlantic Palaeoceanography. Geological Society. London bathymetric information, this work has allowed us Special Publication. 94. 1217-1244. to infer sediment transport processes in the Stoker. M.S. 1997: Mid to late Cenozoic sedimentation on the vicinity of Clonmacnoise. It suggests that the continental margin off NW Britain. Journal of Geological Socieh'. London. 154. 509-515. posts were never there in the first place. An attempt has been made to reconstruct the extent of the main river channel around 800AD by projecting the meander upstream to the north. Geophysical insights on the palaeo-landscape The location of this palaeo-channel determines of the River Shannon at Clonmacnoise and the current regime and depth profile of the river lessons for the medieval engineer. bed at the time the bridge was constructed. G. Duffy’. C. Brown1 and K. Barton' 1 Department of Earth and Ocean Sciences. NUI. Galway. ’ Landscape Geophysical Services. James St.. Claremorris. Co. Mayo. Geological significance of swath bathymetry E-mail: oavin.dulfv g nuioalv.av.ie and backscatter in Lough Corrib and Clew Bay Clonmacnoise is located on the intersection Glynn. B ' C Brown 1 2 and S Rooney 2 between two of the country's largest natural ' Environmental Change Institute. National University of transport routes: a narrow winding esker running Ireland. Galway. Galway: from Dublin to Galway called the Eiscir Riada. and ' Department of Earlh and Ocean Sciences. National the River Shannon which runs roughly north - south University of Ireland. Galway. Galway. from Cavan to Limerick. It was not a surprise when local divers discovered 10 years ago the remains of "»h!wh— Swath bathymetry and backscatter data Joint IQUA/QRA Fieldmeeting to Western have been collected simultaneously using Ireland. 5-10lh April 2005. interferometric sonar over an area of 37 km2 in Clew ************** Bay and 40 km? in Lough Corrib, western Ireland. 2005 Autumn Symposium: ‘Reconstructing The sonar is a phase discrimination system, Changing Climates’. A provisional date of 25lh of operating at a centre frequency of 234 kHz. It has a November has been suggested. maximum swath width of 300 m and can give 100% seabed coverage in waters up to 100 m in depth. The bathymetric resolution can be as good as 0.075 m. High-resolution bathymetric maps of both areas 6. Postgraduate Research have been created for interpretation in terms of geological processes and have been integrated into Glaciation, deformation and till porosity: a Digital Terrain Model. Backscatter is a measure of County Laois. Ireland strength of the echo returned from an object or Aoibheann A Kilfeather patch of seabed. Bathymetry and backscatter have Department of Geography. Queen Mary. University of been used to characterise the seabed and lakebed London geology and can be correlated with the onshore geology. A statistical analysis of backscatter The Quaternary geology of the Irish amplitude has allowed for the generation of an midlands is largely unknown. The first aim of this acoustic facies map describing the distribution of thesis is to describe the results of Quaternary sediment on the seabed/lakebed. The analysis geological mapping, by the author, of County minimises subjective and qualitative interpretations Laois in the midlands of Ireland, with special of the acoustic images. emphasis on the tills. The second aim is to The geology reflects Clew Bay's extensive examine bulk porosity and pore shape, size and glacial history. A terminal moraine marking major connectivity in tills. A review of the literature ice limits during the Last Glaciation (Midlandian) is describing tills and their structures reveals that present. Other features include submerged there has been little research into till porosity. drumlins, submarine palaeo-river channels, The methods used in this thesis include palaeocoastline. the extension of highly faulted rock conventional mapping techniques with particle units offshore and major geological contacts. In size analysis and stone counts. Methodologies Lough Corrib, a NE-SW trending deep channel has have been developed in this research to examine been found. This channel appears to be part of a till pores microscopically using thin section splaying fault system, in accordance with other microstructure analysis. scanning electron faults mapped in the area. The sediments in both microscopy (SEM). experimental pore cast areas have been sampled and corroborate production and x-ray computed tomography. interpretation of the backscatter. Porosity is quantified using digital image analysis of thin section images from the petrographic microscope and SEM. These methods were applied to a selection of tills with diverse 2004 Autumn Symposium Posters properties. The mapping results have substantially Glynn. B.. Brown. C. & Rooney. S. increased the Quaternary data set. and our Geological significance of swath bathymetry and backscatter in Lough Corrib and Clew Bay understanding of glacier dynamics during the last glaciation, for the Irish midlands. Two ice lobes, Duffy. G.. Brown. C. & Barton. K. which moved over a deforming till bed. covered Geophysical insights on the palaeo landscape of the River County Laois: one advanced from the northwest Shannon at Clonmacnoise and lessons for the medieval engineer and the other from the west. During retreat the Eibhlin Doyle lobes deposited complex suites of flow tills and Shallow seismic results for NW of Donegal glaciofluvial sediments. Micromorphological techniques have Eibhlin Doyle Major Slide into Rockall Basin allowed porosity to be related to other till microstructures. Most of the microstructures David Hardy examined, including the pores, are indicative of INSS and Ancient Landscapes either plastic or brittle subglacial deformation and the tvpe and extent of till deformation has been found to affect bulk porosity, pore type and pore 5. Upcoming Events connectivity. [QUA Newsletter April 2005 Viewing tills as deforming glacier beds has landslides Journal of Geology, 113(1)107-114 led to better understanding of till structures, including porosity. The methods and results Knight. J 2005 Controls on the formation of coastal presented in this thesis may be applied to tills in ventifacts Geomorphology, 64 (3-4). 243-254 other glaciated and formerly glaciated regions. (Doctor of Philosophy awarded end of 2004) FitzGerald, D.M and Knight, J, (eds) 2005. High- Resolution Morphodynamics and Sedimentary Evolution of Estuaries Springer, New York 7. Postgraduate Notices Knight. J 2005 The Irish Sea Basin In: Lewis C A. and Richards. A (eds) The Glaciations of Wales |Undergraduate / Postgraduate Training Logaston Press Hereford, 177-188 Knight. J 2004 Subglacial depositional processes in Arctic Research Experiences for Undergraduate the Port Askaig Formation (Neoproterozoic) of Students. The Svalbard Research Experience Ireland EOS (Transactions of the American for Undergraduates (REU) is offering Geophysical Union). 85 (47). Fall Meeting exciting opportunities for students to participate Supplement, abstract C31B-0330 in polar science research projects in Svalbard Norway http //www mtholyoke edu/proj/svalbard/weicome shtml Mitchell, F J G 2005 How open were European primeval forests'? Hypothesis testing using HOLIVAR Training Course palaeoecological data. Journal of Ecology, 93. 168- "Quantitative climate reconstruction and data-model 177 comparisons" Monday June 27th to Friday July 7th, 2005 Mitchell, F.J.G and Cooney, T 2004 Vegetation Location: Meteo-France CIC, Toulouse, France history in the Killarney Valley In: W. O'Brien (ed ) Full funding available for PhD students and young post Ross island Mining, metal and society in early Ireland. doctoral scientists affiliated with European institutions pp 481-493. Bronze Age Studies 6, Department of Archaeology, National University of Ireland, Galway. This course is intended for PhD students and young post doctoral scientists interested in multi- and interdisciplinary Vaughan A P M Dowling, LA., Mitchell FJG, study of Holocene climate variability Offered to both Lauritzen. S.-E , McCabe. A.M and Coxon, P (2004) palaeoclimatologists and climate modellers it covers in a Depositional and post-depositional history of warm single two-week programme of lectures and practical stage deposits at Knocknacran, Co. Monaghan exercises the key themes of the ESF-HOLIVAR Ireland implications for preservation of last interglaciai programme in an integrated way The content of the deposits Journal of Quaternary Science, 19. 577-590 course this year will largely follow the courses presented in London in 2003 and Ghent in 2004 with a larger emphasis on quantitative methods of reconstruction The course is structured in 7 topical modules, each consisting 9. News items of a series of lectures on the state of the art by leading climate-change scientists, related practical exercises, and Colm O'Cofaigh - Trinity College Graduate 1991 group discussion of major research issues has been awarded the Quaternary Research Post-doctoral and PhD students affiliated with European Association's ‘Lewis Penny Medal' (details institutions are invited to apply Successful applicants below). Colm completed a Masters degree also receive full ESF-HOLIVAR funding to attend the course in TCD (On glacimarine sedimentation along the (travel, half-board accommodation and course fees) They SE coast) and went on to do a PhD in Canada. will be expected to present a poster on their research He is now lecturing in the University of Durham. and contribute to a written summary of discussion themes and conclusions to be distributed at the end of the course The medal will be presented to Colm by the Application forms can be found on the HOLIVAR website Association’s President at the Annual General at http://wwwgeogucl.acuk/ecrc/holivar/ or requested from Simon Brewer at brewer@cerege fr Meeting of the QRA that, by coincidence, is to be held in Galway on Thursday 7th April. Lewis Penny Medal 8. Recent Publications Criteria for the award of the medal The Medal and £100 prize money will be Hegarty. S 2004 Limits of Midlandian glaciation in south awarded to a young (normally less than 35 years eastern Ireland Irish Geography, 37 60-76 old) or new research worker, who has been a member of the QRA for at least 3 years, and who Knight, J 2005. Formation of thrust structures in front of coastal has made a significant contribution to the Quaternary Stratigraphy of the British Isles and IQUA Newsletter April 2005 its maritime environment. This is notionally taken to mean Britain, Ireland and surrounding offshore International Workshop on Sub-aerially Exposed areas but adjacent areas of continental Europe that Continental Shelves Since the Middle Pleistocene have relevance to the British Isles may also be Climatic Transistion 9-13 May 2005 Hong Kong www hku.hk/earthsci/other/des fram.htm taken into account. Quaternary Stratigraphy is considered here to include both Pleistocene and Conference of Irish Geographers, 2005. National Holocene records and to be broad-based, University of Ireland, Galway 6th-8* May 2005 encompassing lithostratigraphy, chronostratigraphy, http://www.nuigalway.ie/geography/confer05.html biostratigraphy or other relevant fields. BGRG Spring Field Meeting May 20-22 2005 http://wwww2.Plymouth acuk/BGRG Nominations The candidate should be nominated by his or her Rapid landscape change and human response in the Head of Department, Ph.D. or Postdoctoral arctic June 15-17, 2005, Whitehorse, Yukon, Canada http://www.taiaa net/c-ciarn-north/vukon.html supervisor or any other QRA member 'of standing’ who is familiar with the candidate’s work. International Field Conference and Workshop on Tephrochronology and Volcamsm. * ** ** * ****** ** "Tephra Rush 2005" Dawson City, Yukon Territory, Canada - July 31st to August 8th. 2005 Environmental Sciences Association of Ireland http://conferences eas.ualberta ca/tephrarush2005/ http://www.esaiweb.org/ Earth System Processes 2 (ESP2) meeting (8-11 Aug To any ESAI member who has not been contacted 05, Calgary, Canada), convened jointly by the by ESAI in the last two months, please forward Geological Society of America and the Geological details to Sinead Macken (E-mail)[email protected] Association of Canada, at your earliest opportunity. http //www.geosocietv.org/meetinqs/esp2/ Anyone else can check out our new website at (Special session entitled Sediment Dynamics and www.esaiweb.org Fluid Flow across Continent-Ocean Margins which is convened by Jasper Knight, University of Exeter, UK. ESAI Bursary [email protected]) and John F Bratton (USGS, The ESAI invites applications for a summer student Wood’s Hole, [email protected]) bursary from undergraduate students in Paleoclimate, Environmental Sustainability and Our environmental sciences or environment-related Future PAGES (Past Global Changes) 2nd Open disciplines to support their participation in active Science Meeting (OSM) Beijing, China 10-12 August research during the summer of 2005. 2005 www.caQes2005.org The student will be expected to work under the supervision of a member of academic staff on a International Conference on Glacial Sedimentary project of direct interest to the Department/Centre in Processes and Products University of Wales. a recognised academic Institution on the island of Aberystwyth 22-27 August 2005 httpV/www.aber ac uk/visitors/glaciology/ Ireland. http://www.esaiweb.org/bursar.htm Holivar2006 Open Science Meeting - Natural climate variability and global warming Environmental Change Research Centre, University College London. UK 10. Forthcoming Conferences & 12th-15th June 2006 http://www.holivar2006 org/ Workshops 10th International Paleolimnology Symposium. Duluth. Minnesota, USA June 25-29, 2006 (further details will European Geosciences Union Vienna. Austria, 24 - 29 be coming soon) April 2005 http //www copernicus ora/EGU/aa/eauQ5/ IQUA Sponsors htto://www. nhm.ac.uk/ http://www.roadstone.ie/ http://www asi.ie/ httD://www.epa.ie/ NATURAL f f ils B l HISTORY l £ IS ^ M U S E U M