Geology

At Sulphur Springs Park you are in the middle of a dormant volcano and on the site of the last recorded eruption in St. Lucia in 1766.  As expected, the immediate area is heavily bruised from the intense volcanic activity experienced in the formation of the south western part of the island.  The park’s main attraction is its sulphur springs - an impressive collection of boiling springs and fumeroles that is seated 305 metres above sea level, between the Rabot Ridge and Terre Blanche.  The springs, from which the area gets its name, Sulphur Springs, occurs at the intersection of two fault lines which traverse the centre of a large steep sided volcanic depression, called “Qualibou” caldera. This caldera is about 32, 000 to 39,000 years old.

Sulphur springs

Sulphur Springs has been described as, “the hottest and most active geothermal field in the Lesser Antilles”.  As you walk or drive through the park, you will actually be moving over a magma chamber just about 2 km beneath the area’s surface.  This magma chamber is responsible for heating the rocks above it, which in turn heats a combination of rainwater that seeps into the ground and seawater from the Caribbean Sea that has seeped into the substratum, giving rise to boiling springs with temperatures between 70 – 90oc and fumaroles with temperatures of up to 172oc.  These boiling springs give rise to the world famous therapeutic waters at Sulphur Springs Park, which form the park’s Black Water Pool and the Pool of Love.

Though not adorned in commercial minerals, the area is a mineral lover’s delight.  It has abundant supplies of kaolinite and quartz and smaller quantities of gypsum, alunite, pyrite and geotite.  As with all other geothermal systems the area is bathed in a copious supply of sulphur.  Small supplies of jarosite, which has generated interest from the Wesleyan University of Connecticut, USA, can also be found within the area.