| Previous Site | Next Site |
Earth Science Conservation Review
| Bellevue, Belfast, Co Antrim – Clay-with-Flints |
| Site number: | 1310 | ||
| Locality Type: | Status: | ASSI | |
| Grid Reference: | J32548110 | ||
| Google maps: | 54.66104,-5.94667 | ||
| County: | Council area: | Belfast City Council | |
| Period: | Cretaceous, Tertiary | ||
| Site Description | |
|---|---|
| Introduction: | |
The site is part of a line of quarries, located on the southwest side of the Antrim Road, extending from near Collinward Cottage for almost 900m SSE to the Floral Hall. The quarries, which were in existence at the time of the first Geological Survey of Ireland in the 1860’s, exploited a natural cliff line that exposed both chalk and basalt lava flows. However, quarrying operations had ceased by the 1960’s and today vegetation now obscures the lower parts of the faces. The floor of the quarry is now a secure parking facility and apart from the natural degradation of the rock face there has been no further despoiling of the site. | |
| Description: | |
Site Geology: Ulster White Limestone Formation: The geological resurvey in 1967 recorded a section in the quarry comprising 6m of chalk at the base, overlain by about 1m of Clay-with-Flints with 13m of basalt lava flows forming the main cliff face. Just over 30m of chalk of Campanian age, representing the Late Cretaceous Ulster White Limestone Formation is present in the Bellevue area (Fletcher 1977). The basal part of this sequence comprises the Creggan Chalk, Boheeshane Chalk, Ballintoy Chalk and Glenarm Chalk members, each one with a reduced thickness, overlain by the Garron Chalk, Portrush Chalk and the Ballymagarry Chalk members, the latter member representing the chalk exposed at Site 10 (Figures 2 and 3). Clay-with-Flints: In the quarry, the Clay-with-Flints is exposed at the south end, just above the top of the scree slope below the cliff face. The bed is also exposed some 50m to the south at the level of the road leading to the zoological gardens. Antrim Lava Group: Basalt lava flows forming the upper part of the quarry belong to the Lower Basalt Formation of the Palaeogene Antrim Lava Group. However, it was observed that, at the south end of the section where the palaeo-doline was infilled by the Clay-with-Flints, a tongue of basalt magma had intruded and hornfelsed the adjacent clay matrix and now formed the exposed south wall of the doline. The Clay-with-Flints detail: The topography of the plane of unconformity between the chalk and the Clay-with-Flints in the section at Belfast Zoo varies from relatively flat to one with depressions at least 2m deep in the chalk bedrock (Photograph 44). Accordingly, the thickness of the Clay-with-Flints varies from only a few centimetres, where the deposit covers pinnacles in the chalk surface, to at least 2m where it fills palaeo-dolines. All of these variations are displayed in the cliff section at the entrance to Belfast Zoo. In contrast to other sections the character of the sediment infill of the palaeo-doline exposed at the south end of the section indicates that this solution hollow existed before the Clay-with-Flints was formed and further subsidence did not occur after its infill was completed. There are two main divisions of the Clay-with-Flints at Belfast Zoo (Figure 32). A lower unit, with a very soft pink to pale brown clay matrix and few scattered lapilli, contains small to large flint nodules which are matrix to clast supported. Internally, the flint nodules still retain the grey colour that characterises them when enclosed in the host chalk. At the location of the palaeo-doline in the Zoo section this layer is confined to the lower part of the hollow. At the north end of this section the Clay-with-Flints is about 1m thick and this unit comprises the lower 0.6-0.7m of the bed. The upper unit is represented in all parts of the Clay-with-Flints section at Belfast Zoo. At the south end of the section it is just over 1m thick in the palaeo-doline but thins laterally and is only about 10m thick covering the pinnacle that forms one side of the hollow (Photograph 44). At the north end of the section this unit forms the top 30cm of the Clay-with-Flints. This unit is characterised by its hard to compact dark brown to red and reddish brown clay matrix with abundant lapilli. Small to very large flint nodules, some up to 40m long and often of tabular outline, form a clast-supported framework. All flint nodules have developed a very thick white crust and show vivid internal staining in shades of purplish red to red and pink. While most of the nodules are whole they invariably are highly shattered internally. Any evidence of size grading is obscure in the deposit but there appears to be a concentration of large and tabular nodules in the upper part suggesting an element of flow in the sediment, which would also account for their internal fracturing induced by repeated contact between nodules during transport. In the upper part of the deposit it is evident that many of the very large tabular nodules show an imbrication and lie more or less parallel to the sides of the depression (Photograph 45). | |
| Conclusions: | |
No petrogenetic analyses were carried out on samples from the section at Belfast Zoo where the bed is divided into two contrasting lithologies based on colour, relative concentration of volcanic lapilli and the nature of the flint clasts. However, the very presence of the two contrasting lithologies supports the concept that the Clay-with-Flints is the product of a two-stage process related to an episode of volcanism that evolved, through time, from andesitic to basaltic andesite composition. In this section the variable thickness of the Clay-with-Flints and the distribution of the lower of the two divisions recognised there is, again, controlled by the topography of the underlying chalk land surface. | |
| 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 | |
|---|---|
| Rocks: | Chalk, Clay, Flint, Basalt |
| Access | |
|---|---|
| Approach: | Publically accessible. Disused quarry (Photograph 4) and Nature Reserve, Knocknadona Townland [Grid Ref: J2285 6705], 4.75km NW of Lisburn City centre, Co. Down (Figures 6 and 7).Disused quarry at Bellevue (Photograph 43), in Collinward Townland [Grid Ref: J3254 8110], 1050m NE of the summit cairn on Collinward mountain, at entrance to Belfast Zoological Gardens, 7.2km NNW from Belfast City centre, Co Antrim (Figures 30 and 31). |
| Restrictions: | Publically accessible |
| Record type: | ESCR report | ||
| Entered by: | I J Enlander | ||
| Last updated: | 28 Mar 2019 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Bellevue, Belfast, Co Antrim – Clay-with-Flints, County , site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=1310. Accessed on 2026-11-04. |
| Previous Site | Next Site |