The water issuing from a hot spring is heated by geothermal heat, i.e., heat from the Earth's mantle. In general, the temperature of rocks within the earth increases with depth. The rate of temperature increase with depth is known as the geothermal gradient. If water percolates deeply enough into the crust, it will be heated as it comes into contact with hot rocks. The water from hot springs in non-volcanic areas is heated in this manner.
The first expedition in the direction of present day Malmesbury was undertaken by Jan Wintervogel in 1655, by order of commander Jan van Riebeeck of the Dutch East India Company, three years after the Dutch explorers colonised the Cape. Previously the area around Malmesbury was inhabited by Khoi and San. The area was soon referred to as ‘het Zwarteland’ (the Black Land), Probably because the veld, covered by rhenoster bushes, appeared black at certain times of the year, unlike the greenness of Europe. When ‘het Zwartelandskerk’ (the Dutch Reformed church) was established in 1745, a mere 24 people were living in the vicinity of the mineral spring, still situated, though only as a small fountain, in the town’s centre. The congregation was known as ‘het Zwartelandskerk’ until 1829, when it was proclaimed a town by former governor Sir Lowry Cole and renamed ‘Malmesbury’ in honour of his father-in-law, Sir James Harris, First Earl of Malmesbury in England. On 8 June 1860 the village gained municipal status and was governed by a board of commissioners for nearly 36 years until 1896, when the town council was established. The town developed rapidly and today is the biggest town in the area, generally known as the ‘Heart of the Swartland’
The sulphur chloride in the water was an attraction for many people with ailments such as arthritis would come and seek relief in the spring. The Khoi and San also used to drink the water for the cure of many ailments. Urban legion has it that after the Tulbagh earth quake in September 1969, the spring lost its heat, (I have not been able to find any documented proof) thus the reason for it not been developed in current time.
South African Hot Springs
South Africa has around 74 geothermal springs and 9 boreholes spread over the entire country. All thermal springs are considered to be meteoric of origin as there was very little recent volcanic/tectonic activity in the country. The heating of the water is due to deep circulation along mainly fault zones. The thermal springs are not confined to specific type of geology. A large percentage coincide with metamorphic provinces on the margins of the Kaapvaal Craton, such as the Cape Fold Belt and the Limpopo Belt, while other hot springs are associated with basins and granite terrains within the Kaapvaal Craton. The complex geological formations through which the water circulates may result in chemical contamination of the spring waters. Since the temperatures of South African thermal springs are lower than 70°C, they are used mainly for recreation and tourism. However, the majority of thermal springs are not developed and are used for bathing and swimming by local communities.
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1. [OPTIONAL] Please take a photo of you or your GPS and the Water wheel.
2. Why do you think this water has medicinal traits ?
3. Why do you think the temperature changed after the 1969 Earth quake?
4. What creatures are featured in the fountain?
