ESCR site summary

Earth Science Conservation Review

Summary Full report
Barony Glen	Londonderry

Lower part of Barony Glen, Co.Londonderry, looking east, showing dominant red-purple colour of most of the rocks of the Drumard Member of the Altagoan Formation.

The lowest, most westerly exposures of the Drumard Member in Barony Glen consist of thick fluvial sandstones and green-grey (purple-red stained) mudstones and siltstones.

The fallmaker here is a yellow-purple sandstone; hammer-head rests on an intra-formational conglomerate comprising reworked nodules of pedogenic carbonate in green-grey silty shale.

Most easterly major waterfall in Glen comprises well-bedded purple-red sandstones, fawn sandstones, and purple and green mudstones overlying unbedded purple-red palaeosols with pale yellow carbonate beds; hammer leans against pedogenic calcrete profile.

Rocks
Site Type:	River bank, Stream section
Site Status:	local interest
Council area:	Limavady Borough Council, Magherafelt District Council
Grid Reference:	C732016
Google maps:	54.85724,-6.86018
Rock Age:	Carboniferous (Tournasian)
Rock Name:	Altagoan Formation, Drumard Member, Tyrone Group
Rock Type:	Limestone, Mudstone, Sand, Sandstone, Siltstone
Interest
Other interest:	Fluvial sediments, alluvial plain

Summary of site:

On the western flank of White Mountain, immediately below the cap of Tertiary basalt lavas, around 100m thickness of horizontal Carboniferous rocks are exposed over a length of 320m of the precipitate stream bed. These are the purplish brown to red mudstones, siltstones and sandstones of the Barony Glen Formation for which this is the type locality and section. At about 350 million years old, these rocks are equivalent in age to the Drummard Member of the Altagoan Formation around Armagh.

The frequent occurrence of carbonate nodules (irregular rounded clots) and thin limestone beds indicate that these were soils periodically invaded by fresh water. They were low lying on an equatorial land surface. There are no fossils evident to the naked eye and the processing of sediment for microscopic fossils has proved fruitless.

This section is the standard reference for the extensive development of rocks of this type and age in the north west of Northern Ireland and as such is fundamental to our understanding of them. There are no evident threats to this exposed upland site.

Enlander, I., Dempster, M. & Doughty, P., 2024. Barony Glen, County Londonderry, site summary. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/summary.php?item=301. Accessed on 2024-12-26