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Ballypalady Plant BedAntrim
Degraded ochre pit at Ballypalady, to the south-east of the disused Belfast-Derry railway line, north-east of Templepatrick, Co.Antrim, as seen in June 1998.
Summary Full report
Site Type: Cutting, Railway cutting
Site Status: PASSI
District:
Grid Reference: J263874, J253867
Rocks
Rock Age: Tertiary (Eocene, Palaeocene)
Rock Name: Antrim Lava Group, Interbasaltic Formation
Rock Type: Basalt, Lignite, Tuff
Interest
Fossil Groups: Plant
Other interest: No data, Flood-deposited sediments

Summary of site:

The Plant Bed at Ballypalady remains by far the most important and best studied of Tertiary Palaeocene floras in Ireland. It was almost certainly exposed for the first time in the 1840s when a cutting was made during the engineering of one of Ireland’s first railways. Its first mention in the scientific literature dates from 1862 and the first description appeared in 1869.

The Plant Bed occurs in the Interbasaltic Bed which separates the Lower and Upper Basalt Formations. The Interbasaltic Bed represents a protracted period (probably several hundred thousand years), following the final eruption of the Lower Basalts and before the onset of the major vulcanicity of the Upper Basalts. During that time, deep weathering of the surface of the Lower Basalts created a landscape underlain by a rich red soil, destined to be sealed by the first lavas of the Upper Basalts. The best description of the section dates from 1912 and was recorded from ‘the old quarry near the railway’, which presumably refers to one of the pits at the extreme western limit of the cutting. Here 6m of alternating fine and coarse sediments, red to reddish-brown in colour and consisting almost entirely of weathered basalt fragments, were exposed and the presence of plant material in the finer sediments was noted. The walls of the railway cutting were described as essentially similar. Examination of an extensive collection in the Ulster Museum shows that the plant material occurs as pollens, fruiting bodies and plant fragments which include carbonized woody material, leaf impressions and natural moulds (cavities left as the original material decayed). Consolidating the species described by seven authorities over a period from 1869 to the present time, the floral list for Ballypalady numbers 25 species. A large proportion of these plants would be fairly familiar to us today, including ancestral forms of such trees as red cedar, cypress, pine, yew, hemlock, plane, gum, poplar, alder, willow and possibly walnut and magnolia. The sediments suggest that dense woodland provided the debris that was washed into the gravels and sands of the bed. The range of genera is clear evidence of a warm temperate climate. Ballypalady is a site of key importance and provides the best evidence of plant diversity and climatic conditions in the Palaeocene volcanic province in the British Isles. Sites of similar age near Glenarm and Ballintoy are impoverished in comparison and there are no equivalent deposits in the Scottish component of the same volcanic region. The flora indicates a Palaeocene age, which is entirely consistent with the potassium/argon radiometric dates of the lavas at around 60 million years. There is no exposure of the Plant Bed at the present time but a proposed upgrading of the presently disused railway line offers an opportunity to clear the cutting and leave a vegetation-free stretch of Interbasaltic Bed (incorporating the Plant Bed) for future teaching and research use.


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