Earth Science Conservation Review

Summary Full report
Tullyard Townland streamTyrone
Site Type: Stream section
Site Status: ESCR
Council area: Omagh District Council
Grid Reference: H30117640
Google maps: 54.63533,-7.53385
Rocks
Rock Age: Carboniferous (Visean)
Rock Name: Bin Mountain Sandstone Formation, Tullyard Conglomerate Member, Tyrone Group
Rock Type: Conglomerate
Interest
Minerals: Quartz
Other interest: Marine sediments

Summary of site:

The Tullyard Conglomerate Member stratotype, the site which gives the member its name and defines its features, forms both banks of this deeply cut, east-flowing stream. Its estimated thickness of between 4 and 5 m is calculated from a number of discontinuous outcrops including the waterfall to the west.

The rock fragments in the conglomerate are small, generally less than 5 mm across, although a few reach 1.5 cm. They are mostly of white quartz (a few are pink) in lime-rich sandstones. All grains are well rounded indicating a long history in turbulent water.

The conglomerate is important because it marks the base of the Bin Mountain Sandstone Formation, an early Carboniferous rock with fossils giving an age in the Chadian stage, around 345 million years ago.

All stratotypes are essential markers in the geological history of their areas and this one provides useful information of the environment at the start of Bin Mountain Sandstone times. It should be preserved.

 Enlander, I., Dempster, M. & Doughty, P., 2024. Tullyard Townland stream, County Tyrone, site summary. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/summary.php?item=222. Accessed on 2024-12-26

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