A kind of natural champagne?

In the past here were laid water pipelines to dry the nearby aragonite mines. The groundwater here is warm and rich with carbonic acid and easily dissolves large amounts of lime along its way. Further, the water goes through iron pipelines – and carbonic acid dissolves iron as well.

Water with carbonic acid is the same well-known carbonated water and… yes, we all know: such water releases lots of bubbles. Sometimes the power of these bubbles forces the water upwards – we know very well the wild reaction of warmed and well-shaken champagne.

Something similar happens in Analavory. Here the carbonated water, rich with lime and iron, has rushed down along the pipelines and finally reached the daylight at the bank of Mazy River, where the pipelines end. CO₂ is released as bubbles and the acidic water gushes upwards like champagne from the bottle. Then it becomes colder and neutral and precipitates the dissolved lime and iron. As a result around the mouth of these artificial “geysers” form mounds of travertine, colored in rusty orange color by the dissolved metal pipelines.

Water finds the lowest rim at the top of the mound and overflows it. The rim in this place is layered with new layers of travertine, it rises higher and water has to find a new way elsewhere. This repeats over time and the mound grows higher and higher. The mounds of Analavory Geysers are more than 4 m high.

Cold water geysers!

Such a phenomenon is called cold water geyser. Although this is not the true and "noble" steam-powered geyser, it is a wonderful and interesting landmark. Such geysers, for the most part, are created by the activity of man, releasing the carbonic acid from the groundwater with boreholes.

In Analavory there are four (some sources mention five) cold-water geysers. Most of the time, the carbonated water spouts 0.2 – 0.3 m high, but sometimes it happens that the vents are blocked by the precipitated lime and, as the barrier is broken, the water is spouting up to 3 m high. Some sources mention that in the past the water was gushing even 20 – 25 m high.

Even if man-made and not a true geyser, this site is very attractive. Analavory Geysers gradually become well-known tourist attractions and there has been installed basic tourist infrastructure.

References

1. J. Alan Glennon, Rhonda M. Pfaff, The Operation and Geography of Carbon Dioxide-Driven, Cold Water "Geysers". 2004.

Analavory Geysers are included in the following list:

Unique lake

Lake Bogoria is one of Rift Valley Lakes. Each of these lakes is unique and Lake Bogoria is not an exception. This lake is alkaline – with a pH of 10.5 at the western bank. Lake water is twice as saline as seawater. Lake gets water only from the hot springs and some perennial rivers and it has no outlet.

As there is no outlet, the level of the lake is regulated just by the rain and heat. This 34 km long lake might rise or fall by 0.15 – 0.3 m in a rather short time.

The alkaline, warm lake water is excellent media for cyanobacteria Arthrospira fusiformis and some other microorganisms. These organisms serve as a food for lesser flamingo (Phoeniconaias minor) and some other birds. In the lake live approximately 0.5 million flamingos – the highest density of these birds worldwide and approximately half of world’s population of these beautiful birds. Sometimes the number of the birds increases up to 2 millions.

Hot springs and geysers of Lake Bogoria

As in many other places in the Great Rift Valley, the volcanic heat here is not far away. The ground here is formed by geologically recent volcanic rocks from Miocene – Pleistocene.

Around Lake Bogoria are some 200 hot springs with water temperatures from 39 to 98.5° C. Nearly all these springs are very close to the lake or – even inside the lake.

There are several larger groups of hot springs around Lake Bogoria, four of these groups are known geysers.

Lake Bogoria hot springs, in general, have a high content of CO₂ gas – this is one additional reason for the wild boiling of the springs.

Some 60 hot springs with 6 geysers are located in Loburu. Further south is Chemurkeu group with 40 springs, including 4 geysers. At the south-eastern end are Koibobei springs with at least 3 geysers. At the eastern side are Losaramat springs with 17 springs, 3 geysers among them. Together – at least 16 geysers. Since 1975 here have been registered at least 18 geysers, but several have disappeared now.

All geysers are located very low – almost at the level of the lake or even below it. As the level of the lake changes, some geysers are inundated and stop their activity but some others start to explode. Whole colonies of specific microorganisms are linked to these hot springs and geysers.

Loburu geysers

Loburu Hot Springs form the largest geothermal field at Lake Bogoria. Loburu river has formed a small delta at the western bank of lake and part of the hot springs are to the north from river and part – to the south. Springs are powerful, they form short streams. Part of the hot springs have formed small pools, some more than 2 m deep. Some springs instead of pools have formed cones. Just in few places there is observed thin layer of siliceous sinter deposits – an indication of geyser activity in the recent past. Such geysers without siliceous sinter (geyserite) are rare in the world.

In the northern group are some 32 hot springs. 3 of these springs are perpetual spouters (hot springs which shoot water in the air without interruption) but none is geyser. Some 11 springs have travertine deposits around them.

The southern group in August 2007 (1) had some 20 hot springs above the lake level and several more under the lake level. Temperature of springs is between 39 and 98.5 °C. At the northern end of southern group are located six geysers.

Five geysers belong to the group named KL19 – their vents are close together, some metres apart. One of these geysers in 1995 was up to 3.5 m high, erupting every 5 – 8 minutes, later it became less powerful. Approximately 30 m to the north is geyser KL30. All these geysers are not active at the same time. For example in August 2006 the geyser KL30 erupted at regular 45 minutes interval, reaching 5 m height, but already in 2007 the rising level of lake suppressed its activity.

Geysers are littered with boulders and pieces of wood – local people throw them in the geysers to initiate eruptions.

References

1. Robin W. Renaut, R. Bernhart Owen, John K. Ego, Recent changes in geyser activity at Loburu, Lake Bogoria, Kenya Rift Valley. 2008.

Loburu Geysers and Hot Springs are included in the following article:

These springs are located to the south of the most famous Lake Bogoria geysers – Loburu Geysers.

Chemurkeu hot springs are located close to the lake, some springs are even inside the lake. In total there are 40 hot springs, 4 geysers among them. One geyser is up to 1.2 m high, one is less than 0.3 m high. Geysers have formed carbonate terraces.

Interesting feature here is: large, flat crystals of aragonite, which grow up to 4 cm long.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

Chemurkeu Hot Springs are included in the following article:

This geyser is located in a larger group of hot springs. In this group are located two more geysers that are less impressive – 0.3 – 0.7 m high.

Koibobei Geyser is active only when its vent is exposed. This geyser is located close to the lake and when the level of the lake rises, it is inundated and does not "work" anymore.

Koibobei geysers have not formed sinter or travertine around them.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

Koibobei Hot Springs and Geysers are included in the following article:

Losaramat geothermal area has 17 hot springs with 3 geysers among them. Each of the geysers is some 0.7 m high. These springs are fed by a comparatively deeper aquifer, where water temperatures reach 170°C – but at the surface, these temperatures are lower, between 64 and 98.5°C.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

Losaramat Hot Springs and Geysers are included in the following article:

Deeper in the ground the temperature of the water reaches 180°C, but at the surface, the temperature of the water is 81 – 96°C. There is found opaline silica which formed when these hot springs were still inundated by the lake water.

In 1902 here (above the lake level) existed springs which on a regular basis erupted – geysers. Over the last decades, geysers have not been observed here anymore.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

Soro Hot Springs, Ol Kokwe Island are included in the following article:

This island is crossed by a fault line – Turkana Rift – in the north-east – south-west direction. In the southern part of the island, there are observed hot springs and steam vents, fumaroles, and solfataras.

In 2004 here was described one geyser. Since then there have been no reports about geyser activity here.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

North Island Geyser is included in the following article:

Logipi Geyser was located near the base of the Samburu escarpment. Travelers in the 1930s reported that the geyser was erupting at regular intervals, discharging large volumes of water. The height of the geyser reached 1.2 m. The water was rich with minerals and there was formed a sinter basin in the front of the geyser.

Later the power of the geyser decreased, it turned into a perpetual spouter. An expedition in 1990 found here just boiling springs.

References

1. T. Scott Bryan, The Geysers of Yellowstone, fourth edition. 2008. Boulder.

Logipi Geyser is included in the following article:

Lowland rainforest

Buranga springs are located close to Ruwenzori Mountains, at the base of the Bwamba escarpment. This remote corner of Uganda is covered with the only remaining East African lowland tropical rainforest. This forest is especially rich with species – here meet animals and plants of western and eastern tropical Africa.

Three groups of hot springs

Buranga springs have formed their own small ecosystems in this lush forest attracting numerous birds (due to swamps around the springs) and animals (due to salt coming out from the depths of Earth). In the springs have been found endemic microorganisms – two previously unknown strains of thermophilic Geobacillus bacteria.

There are three separate groups of springs, located some 700 m from each other.

Nyansimbe spring (Nyasinbi, tourist guides call it – male pool) has formed a swamp and is acessible only in dry season. This spring has developed a carbonate cone with clear pool of hot water (86°C) in it. Pool has a diameter of 30 m, depth is more than 5 m. Flow rate is 15 l/s.

Mumbuga springs (Mubunga, named female pools by tourist guides) are numerous hot springs in area 60 x 40 m, all springs are depositing carbonates. These springs also can be accessed in dry season. One spring has built 1.5 m tall travertine cone with terraces. Water here forms some 50 cm high fountain, rising above the pool. Water is bubling and emanating gases. Flow rate of these springs is 6.5 l/s. Temperature of spring reaches 98.4°C.

Kagoro springs are the southernmost. They take an area of 50 x 15 m, enclosed by rainforest. Here the springs also have built up to 1.5 m high travertine cones. At the base of the largest travertine cone are sulfur deposits – the only ones in Buranga. Temperature of water is 60 – 91° C.

Rift and earthquakes

Geothermal activity of Buranga springs is linked to the tectonic activity of rift (Albertine graben – part of the East African Rift System). The hot water here might be rising along the active faults of Earth’s crust.

Scientists have noticed that after each earthquake hot springs are changing. It happens that some of the older springs disappear and new ones start.

References

1. Norbert Ochmann, Michael Lindenfeld, Paula Barbirye, Christopher Stadtler, Microearthquake Survey at the Buranga Geothermal Prospect, Western Uganda, Proceedings, Thirty-Second Workshop on Geothermal Reservoir Engineering. Accessed on June 15, 2011.
2. Catherine Nyakecho, Preliminary Environmental Impact Assessment for the Development of Buranga Geothermal Prospect, Uganda. 2008. Accessed on June 15, 2011.

Buranga Hot Springs are included in the following article:

Geysers were active here up to 1979 – the last geyser was erupting erratically, up to 1.8 m high.

Now here are located very hot and powerful springs, with water temperatures as high as 96°C. A platform of geyserite with cones of former geysers has been preserved.

References

1. T. Scott Bryan. The Geysers of Yellowstone, Fourth Edition. 2008, Boulder.

Lake Abaya Hot Springs are included in the following article: