| Site Type: | Quarry (working) |
| Site Status: | local interest |
| Council area: | Ballymena District Council |
| Grid Reference: | D101071 |
| Google maps: | 54.89987,-6.28375 |
| Rocks |
|---|
| Rock Age: | Tertiary (Palaeogene) |
| Rock Name: | Antrim Lava Group, Interbasaltic Formation, Upper Basalt Formation |
| Rock Type: | Basalt, Bauxite, Ironstone, Laterite, Lignite |
| Interest |
|---|
| Minerals: | Analcime, Calcite, Chabazite, Gyrolite, Natrolite, Saponite, Thomsonite, Zeolites, Mesolite, Apophyllite |
| Other interest: | amygdales, Extrusion |
There are three areas of interest at Clinty Quarry. The first area is located within the site about 60m north of the main office. It comprises an inclined road-cut and an adjacent 3m-high, 15m long cliff section exposing laterites of the Interbasaltic Formation (Palaeogene) and an overlying lava flow of the Upper Basalt Formation. The exposure is best on the east side of the road-cut, where the uppermost 1m-thick part of the Interbasaltic Bed contains layers of pisolitic ironstone. The black rounded pisoliths, typically 2-8mm in diametre, are magnetic and comprise a mixture of hydroxides and oxides of iron including magnetite. The lowermost part of the overlying Upper Basalt Formation has a pillowed appearance, and a glassy (hyaloclastite?) layer is evident within the flow about 1m above the contact. The second area of interest is the lateritic bauxite quarry located at the northwest side of the main quarry. Vertical sections through the Interbasaltic Formation show a variety of colours and textures, and residual core-stones of basalt. These occur as ‘giant's eyes' within the bauxite, and as metre-diameter rounded boulders that have been separated out and stockpiled during quarrying operations. The third area of interest is the main basalt quarry which works a 15-20m thick, massive lower flow of the Upper Basalt Formation. Zeolite-bearing amygdaloidal material is fairly scarce in the basalt. Saponite-filled pipe amygdales were noted in loose material, and towards the southern end of the active area, amygdaloidal basalt containing zeolites and calcite. Zeolites include thomsonite, natrolite, mesolite, analcime, chabazite and gyrolite. Apophyllite has also been found. On occasions when quarrying has inadvertently cut into the underlying Interbasaltic Formation, lignite has been found in the form of tree trunks and roots in situ within the lateritic bauxite.
The vertical sections through the Interbasaltic Formation expose good examples of rock weathering and laterite development. Comparisons can be made with regions of present-day lateritic soil development such as Australia, where pisoliths commonly form at the ground surface and are underlain by laterites and deeply-weathered rock.
