Lough Bunny is located to the east of the Burren uplands, halfway between Corrofin and Gort. It is a shallow, oligotrophic lake that sits on the limestones of the Burren Formation. Oligotrophic lakes are lakes that contain very low levels of nutrients.
The low-lying limestone area east of the Burren uplands is called the Gort lowlands. Deeply weathered over millions of years and further eroded by glacial advances, many parts are barely above sea-level. It is thought that the shale and sandstones that cover south and west Clare once extended over the limestone as far as Slieve Aughty in east Clare. The development of rivers on these older mountains eroded the shale and sandstone cover earlier on this side of the Burren and exposed the limestone to the dissolving effect of rainwater. The limestone of the Gort lowlands has been dissolving for a much longer period of time, perhaps several million years longer, that the central and western Burren limestone.
When water levels are low the lakeshore shows several interesting features. Near the water’s edge the limestone is smooth and flat and fissures are scarce. This is because the lake produces a carbonate marl which covers the lake floor and protects the underlying limestone from the dissolving effects of rainwater. In the field beside the lake normal karst features are obvious such as the deep fissures called grikes.
These are the result of long periods of time exposed to the effect of rainwater. At the upper edge of the lakeshore between these two extremes you will see a series of circular dissolution pits, many of these are connected by narrow channels formed as water flows out of the pits and down the gentle slope towards the lake, gradually dissolving the limestone as it flows. If they continue to be exposed to rainwater they will eventually develop into the clints and grikes typical of the Burren.