Southeastern Ireland Research Articles

Geologists's association—Irish geological association: Field meeting in Anglesey and southeastern Ireland 4–11 June 1977

This field meeting was designed to compare the rocks of the Mona Complex in Anglesey with similar groups of rocks which occur immediately across the Irish Sea near Dublin and in Co. Wexford. On Anglesey localities illustrated the rock units which comprise the Mona Complex, including the classic blueschists and a variety of metasedimentary and metavolcanic rock-types; mylonites, pillow lavas, pelagic ocean floor sediments, turbidites and the spectacular Gwna melange (olistostrome). In Ireland at Howth and Bray near Dublin turbidites, olistostromes and other types of slump deposits were inspected. In southeast Ireland the Cullenstown Fm. with further olistostrome deposits, and the amphibolite facies Rosslare Complex (2400 Ma) were visited. On the basis of the observations made at all the localities a plate tectonic model of the evolution of the southern part of the Irish Sea region in the Late Precambrian and the Lower Palaeozoic was proposed.

Lower Cambrian palynomorphs from Howth, Co. Dublin

AbstractEvidence for the age of the Bray Group in southeastern Ireland is very limited. In this paper, a sample from the Gaskin's Leap Formation of the Bray Group succession in the Howth peninsula is shown to contain acritarchs of probable Lower Cambrian age.

The Late Devensian vegetation of Ireland

The vegetation of the Late Devensian period in Ireland is reviewed. New investigations at Ballybetagh, Co. Dublin, Dunshaughlin, Co. Meath, Glenveagh, Co. Donegal and Poulroe, Co. Clare, are reported. A sequence of phases of vegetation development for the Dublin region is described and regional variation elsewhere in Ireland discussed. Pollen influx values for two Late Devensian sites in southeastern Ireland are reported. A case is made that the Juniperus-Empetrum phase between 12400 and 12000 B.P. was the warmest phase of the Late Devensian. The reason for absence of birch woodland in late-glacial Ireland is discussed. Evidence for widespread soil erosion at the end of the Juniperus-Empetrum phase is presented. The occurrence of a corrie glaciation at Lough Nahanagan in the Wicklow Mountains in the Artemisia phase is documented. A radiocarbon chronology for events in the Late Devensian of Ireland is proposed

A new section in the lower coal measures (Westphalian A) of Up Holland, near Wigan, Lancashire

The cutting made recently for the Up Holland by-pass between Crawford and Up Holland has exposed 171 m. of lower Westphalian measures in an area which for many years has provided magnificent sections throughout the lower two thirds of the Carbonicola 1 lenisulcata Zone. The new section, which is described, includes the upper third of the Zone. Tonge's Marine Band overlies a 3· metre band of non-marine shells new to the area and including Carbonicola extenuata Eagar and C. extima Eagar. This shell band provides faunal links with successions in the Burnley district, in Yorkshire and in south-eastern Ireland, and confirms the value of the latter species as a horizon marker. A second non-marine shell band, 23·8 m. above Tonge's Marine Band, has correlatives locally and in the Burnley Coalfield. In Up Holland by-pass cutting the band yields burrows referred to Pelecypodichnus Seilacher, associated with very small Carbonicola cf. bellula (Bolton). The type assemblage of Carbonicola bellula, from near the top of the Namurian south of Burnley, is similarly related to Pelecypodichnus, and the significance of both these associations is discussed. It is concluded that Pelecypodichnus provides some direct evidence of the way in which non-marine bivalve faunas colonised the deltaic area of the Pennine region after the recession of marine incursions in late Namurian times. The Pasture Mine Marine Band was probably met in an abandoned shallow shaft on the margin of a quarry adjacent to the cutting. The same quarry has yielded a possible representative of the Ditton Marine Band near the base of the C. communis Zone.

Further Remarks onPlatycalymeneand the Segmental Relations of Trilobite Eyes

The specimen referred to by Stubblefield as indistinguishable from Platycalymene duplicata (Murchison) is from the Raheen shales of Passage East, County Waterford, southeastern Ireland.

A New Passage Grave Group in South Eastern Ireland

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