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Drumard WaterLondonderry
Summary Full report
Site Type: Stream section
Site Status: PASSI
District: Magherafelt District Council
Grid Reference: H7993, H7994
Rock Age: Carboniferous (Tournasian)
Rock Name: Altagoan Formation, Drumard Member, Tyrone Group
Rock Type: Mudstone, Sand, Sandstone
Other interest: No data, No Data, alluvial fan

Summary of site:

The river bed of the Drummard Water consists of a series of thinly bedded red and grey sandstones and brown mudstones; some of the mudstones contain thin sandstone beds. Above them in the succession are more mudstones containing dark organic particles, probably plant remains, while the presence of carbonate nodules suggests that soils were forming in the same environment.

This is the finest section of the Drummard Member (the basal unit of the Altagoan Formation) and it is the stratotype, i.e. the most complete section known and the standard for comparison with other occurrences. Plant spores from the rocks below and above this member place it in the Chadian stage of the Tournaisian, a major and early epoch of the Carboniferous period, making these rocks about 347 million years old. The sea at this time was periodically but progressively invading the lowlands of a large continent moving gradually northwards on its tectonic plate towards the equator and beyond. This area was on the southern fringe of the landmass backed by the infant Appalachian Mountains. The Drummard rocks suggest an inshore, sometime emergent, environment with little sedimentation; this interpretation is supported by the presence of soil carbonate nodules, later reworked by water. There are no evident threats to the site.

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