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Earth Science Conservation Review
| Altakeeran Burn, Glenshane Pass – Clay-with-Flints |
| Site number: | 1304 | ||
| Locality Type: | Status: | ESCR | |
| Grid Reference: | C77770613 | ||
| Google maps: | 54.89698,-6.78891 | ||
| County: | Council area: | Causeway Coast & Glens Borough Council | |
| Period: | Cretaceous, Tertiary | ||
| Site Description | |
|---|---|
| Introduction: | |
This natural exposure of the Donald’s Hill Ignimbrite Formation (DHIF) along the northwest edge of the Antrim Plateau is the lateral equivalent of the Clay-with-Flints horizon. It occurs on the south side of Craigmore (395m) in the deeply incised, southflowing stream that eventually joins with Altakeeran Burn about 200m downstream of the exposure (Photograph 16). This site was selected for its accessibility, for the relative clarity of the exposure and particularly for the unusual geological history that the site reveals, which is at variance from that displayed at all other selected localities. This site is also one of the few exposures of the DHIF in the area of the Glenshane Pass (Photograph 17). | |
| Description: | |
Site Geology: Sherwood Sandstone Group: At this locality, exposure of the DHIF is confined to the east face of the deeply incised stream valley. Downstream, and in the absence of chalk of the Late Cretaceous Ulster White Limestone Formation, lying stratigraphically below the DHIF are red-beds of the Early Triassic Sherwood Sandstone Group (Photograph 18). These consist of brick red to purplish red fine- to medium-grained sandstone with millet seed sand grains and cross laminations and mudstones with desiccation cracks. The sandstone beds are inclined at 30o to the WNW, sub-parallel to a major NNE-SSW orientated normal fault with a dip slip component to the northwest. Bedrock, on the downthrow side of this fault, consists of weathered basalt lava of the Lower Basalt Formation of the Palaeogene Antrim Lava Group. Donald’s Hill Ignimbrite Formation: North and northwest of this site basalt lava of the Antrim Lava Group form the precipitous edge to the Antrim Plateau, fringing the northern part of the Glenshane Pass. It also demonstrates the southward thinning and gradual disappearance of chalk of the Ulster White Limestone Formation beneath the DHIF, and the eventual disappearance of the Sherwood Sandstone Group southwest of this locality along the west flank of the ridge comprising Corick Mountain, Glenshane Mountain and White Mountain and Mullaghmore. In the latter area the DHIF rests unconformably on the Early Carboniferous Barony Glen Formation. However, despite the length of outcrop of the DHIF and the frequent occurrence of large loose blocks indicating its presence in an area, it is very seldom exposed in the area adjacent to the Glenshane Pass. Additional exposures of the DHIF are found on the west side of White Mountain, [Grid Ref: C7348 0200] where it rests on the Barony Glen Formation, and on the northwest side of Glenshane Mountain [Grid Ref: C7481 0322] where the 1m bed succeeds the Sherwood Sandstone Group and occurs at the base of 20-25m high cliffs composed of basalt lavas of the Antrim Lava Group. | |
| Conclusions: | |
Because of the relative proximity of the stratotype section of the DHIF at Donald’s Hill, 11.3km NNW of this site, no description or analyses of the ignimbrite are included here (see Site 5). No divisions of the DHIF at this site were found and thus no vertical section is appended (Photograph 19). | |
| Notes: | |
The full series of Clay-with-Flints records is as follows: Record no. 1300 Introduction to Clay-with-Flints of Northern Ireland Record no. 1301 Belshaw’s Quarry – Clay-with-Flints Record no. 1302 Gibson’s Quarry, Portadown – Clay-with-Flints Record no. 1303 Devlin’ Quarry, Moneymore – Clay-with-Flints Record no. 1304 Glenshane Pass – Clay-with-Flints Record no. 1305 Donald’s Hill – Clay-with-Flints Record no. 1306 Tircrevan Burn – Clay-with-Flints Record no. 1307 Ballycastle – Clay-with-Flints Record no. 1308 Demesne Quarry, Glenarm – Clay-with-Flints Record no. 1309 Magheramorne Quarry, Larne – Clay-with-Flints Record no. 1310 Bellevue, Belfast, Co Antrim – Clay-with-Flints Record no. 1311 Soldierstown Quarry, Moira – Clay-with-Flints | |
| Keywords | |
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| Rocks: | Chalk, Clay, Flint, Basalt |
| Access | |
|---|---|
| Approach: | Private land. South-flowing (Photograph 16) western tributary of Altakeeran Burn [Grid Ref: C7777 0613], 610m NNE of Eden Bridge, Eden Townland, 9.35km NW of Maghera town centre, Co. Londonderry (Figures 15 and 16). |
| Restrictions: | Private land |
| Record type: | ESCR report | ||
| Entered by: | I J Enlander | ||
| Last updated: | 28 Mar 2019 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Altakeeran Burn, Glenshane Pass – Clay-with-Flints, County , site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=1304. Accessed on 2026-11-03. |
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