Musa acuminata Colla, 1820 - banana trees at Watling’s Well Banana Hole, southern San Salvador Island.

These banana trees are left over from the 1700s to 1800s Plantation Era. They are growing wild next to a type of karst feature called a banana hole, which are relatively small, relatively low caves having a subcircular shape in plan view. Traditionally, banana holes are interpreted as phreatic dissolutional features that formed at the top of an ancient groundwater lens (at the water table), away from the margins of a carbonate island. Like flank margin caves, banana holes originally had no entrances to the surface. With erosional denudation of limestone bedrock surfaces, banana hole ceilings collapse, resulting in a cave entrance.

Recent karst research has shown that banana holes are immature flank margin caves that started to develop at the margins of former fresh-groundwater lenses, where mixing with seawater occurred (see Myrloie et al., 2012). Freshwater-seawater mixing zone waters have high aggressivity, resulting in calcium carbonate dissolution and cave development.

Once the ceiling of a banana hole collapses, the cave becomes a local depocenter for sediment and organic debris. This results in the development of a decent soil (decent for the Bahamas). In the Plantation Era, the soils in banana holes were used to grow certain agricultural crops such as banana trees (they are not true trees, however).

Classification: Plantae, Angiospermophyta, Zingiberales, Musaceae

Reference cited: