ESCR - Carganamuck Quarry

Introduction to the database

Selected sites to visit

Additional NIEA information

Earth Science Conservation Review

Summary Full report
Carganamuck Quarry	Armagh

Site number:	279	File Number:	H84
ESCC:	EA
Locality Type:	Quarry (working)	Status:	ESCR
Grid Reference:	H878498 Centroid
Google maps:	54.3897,-6.64842
County:	Armagh	Council area:	Armagh City, Banbridge & Craigavon Borough Council
Period:	Carboniferous
Stages:	Brigantian, Visean
Lithostrat:	Armagh Group

Site Description
SW end of Carganamuck Quarry, near Armagh City, Co. Armagh.
Highlights:
Brigantian limestones and shales of the Armagh Group are superbly displayed in Carganamuck Quarry. An excellent example of a palaeokarst surface is developed there. Abundant corals and brachiopods may be collected from the quarry.
Description:
Carganamuck Quarry is located on the south bank of the Callan River 4.25km north of the Mall in Armagh City. It is about 300m long but rarely exceeds 50m in width and is currently operating only at its SW end. Bedding in the quarry is inclined to the NW at 10 deg. and limestone bedding surfaces dip beneath the channel of the Callan River, about 100m north of the current working face. Near the top of the high north face is a palaeokarst horizon. Main quarry face showing uneven bedding of Brigantian limestones of the Armagh Group, and occurrence of a thick palaeokarst horizon in upper part of succession. This is about 0.6-0.7m thick and is bracketed, at the base and top by bright red clays. Detailed view of thick palaeokarst horizon, bounded top and base by red pedogenic mudstones. The nature of the bedding in the limestones that occur stratigraphically below the palaeosol tends to be relatively thin and of even thickness. The lowest of these limestones is located in the SW corner of the working quarry and consists of medium grey, fine to medium-grained packstone, with some cyanobacterial coatings to shell debris. Regularly bedded Brigantian limestones representing lowest strata of Armagh Group in this quarry. It also contains algae and foraminifera as follows: ALGAE: Calcifolium sp., Draffania biloba, Kamaeniid FORAMINIFERA: Archaediscus moelleri, Cribrostomum sp., Earlandia sp., Endostaffella sp., Endothyra sp., E. ex. gr. phrissa, Eostaffella mosquensis, Gigasbia sp., Globoendothyra sp., Howchinia bradyana, Paraarchaediscus sp., Planoarchaediscus concinnus, Pseudoammodiscus sp., Tetrataxis sp., Valvullinella sp. The presence of Howchinia bradyana indicates an age no older than late Asbian. The lack of Koninckopora and Brigantian index taxa favours an earliest Brigantian age. Bedding in the limestones located stratigraphically above the palaeokarst surface tends to be more variable in thickness and consists frequently of very coarse skeletal packstones and fine grainstones. Thin purple-red shales develop commonly between beds of these upper limestones. Incipient development of transitory palaeokarst surfaces also appears to have occurred regularly at and above the major palaeokarst horizon and many bedding surfaces of these limestones are leached, highly irregular and are smeared with purple clay and reworked bioclasts. Loose block of Brigantian limestone showing bedding surface crowded with brachiopods, in particular large convex pedicle valves of Gigantoproductus sp (with strong fluting - a feature especially diagnostic of Brigantian species). A prolific macrofauna is present in the limestones in this quarry and is dominated by large brachiopods and corals as follows: BRACHIOPODS: Gigantoproductus sp. nov. aff. elongata, Gigantoproductus sp. nov. aff. meharezensis, Gigantoproductus sp. SOLITARY CORALS: Dibunophyllum bipartitum, D. konincki Limestone bedding surfaces are occasionally crowded with brachiopods of which the very large specimens of Gigantoproductus are spectacular. Of special interest is the presence of strong fluting on their convex pedicle valves which suggests a Brigantian, possibly late Brigantian, age. The pervasive pale purple colour of many of the limestones and most of the shales may be derived from groundwater percolating downwards from the overlying Triassic red-beds, which are now exposed on the north bank of the Callan River, 300m from the quarry.
Conclusions:
The Brigantian strata that occur at the top of the Armagh Group in Subarea-6 outcrop over a relatively small part of the whole Carboniferous outcrop. Nevertheless they are superbly exposed in Carganamuck Quarry and yield an abundance of well preserved specimens of brachiopods and corals. In Northern Ireland it is unusual to find large exposures of Brigantian strata that yield such superb fossils.
Notes:
For information on other sites in Subarea-6 see Key Site 1179 - Subarea-6; Armagh-Benburb.

Keywords
Rocks:	Limestone
Fossil Groups:	Alga, Brachiopod, Coral, Foraminifera
Fossil List:	Howchinia bradyana
Structures:	palaeokarst
Relations:	Marine sediments

Measurements
Length:	~300 m	Width:	~50 m	Height:
Depth:		Area:

Access
Approach:	The quarry is located on the south bank of the Callan River 4.25km north of the Mall in Armagh City.


Map(s):	See 1:50,000 O.S. Sheet 19 (Armagh).
Record type:	ESCR report
Entered by:	Doughty, P.J.

Enlander, I., Dempster, M. & Doughty, P., 2026. Carganamuck Quarry, County Armagh, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=279. Accessed on 2026-11-06.

Finding out more

Acknowledgments

© National Museums NI 2003-24