The Blue Lagoon occupies a basalt lava flow on the Reykjanes Peninsula near the international airport, while Landmannalauger, a popular outdoor sports camping base in southern Iceland, sits in an area of rhyolitic volcanics. The basalt is of a very low-silica and low-sodium type (theoleiite), while the latter rhyolite has a very high silica content. Yet it is silica that make the waters of the Blue Lagoon so distinctive.
From Keflavik Airport to the Blue Lagoon, and on to Reykjavik
The Blue Lagoon spa owes its existence to the Svartsegi Geothermal plant, constructed in 1976 within the Grindavik lava field and fissure swarm (the fissures can be seen from the airplane). The plant pipes up geothermally altered spring water. As K.R. Ragnarsdóttir describes in Geochimlca et Cosmochimica Acta 48:1535-1553 (1984), chemical reaction with seawater seeping into the lava at depth causes the theoleitic basalt to give up its silica and sodium to the springs. Once used by the plant, these silica-saturated thermal springwaters are discharged over the lava field. Silica precipitates out to form a white muddy ooze and line the rocks with a slick white covering. The silica mud was found by a plant worker to aid in the cure of chronic psoriasis, and from 1986 the Icelandic government funded research on the waters and the establishment of a clinic for treatment. Tourists and natives alike benefit from the additional spa facilities.
Totally exposed to the sun at the Blue Lagoon, you’ll need your hat and sun lotion — or instead, smear yourself with the white silica ooze. Big wooden tubs of this mud are offered; you can be modest and only cover your face, or go whole-hog and slap it on your entire body. At 137 mg in 1 kg of water, the high levels of silica precipitate turns the water white (photo) by scattering incoming light.
Jon Olafsson reports in Clinics in Dermatology (vol. 14: 647-51, 1996) that the spa water has physical characteristics (37°C, pH 7.5, salt content of 2.5%) that should support considerable flora, but Blue Lagoon is virtually sterile. Only a few types of innocuous bacteria and blue-green algae can survive in it. Olafsson speculates that high temperature together with high silica and salt content make bacteria more sensitive to ultraviolet rays. But to be safe, bathers are required to wash before entering the lagoon. Thus, even a plane-load of people cannot contaminate the water, which moreover circulates every 40 hours. So relax with your many fellow travellers and reap the benefits enjoyed by Icelandic inhabitants.
Landmannalaugar in Fjallabak Nature Reserve
In the middle of the southern highlands just north of Torfajökull glacier, Landmannalaugar is nowhere near as convenient as the Blue Lagoon. In fact, you will have to work hard to get there. At 600 m m.s.l., Landmannalaugar is accessible only by dirt road, open only during the summer months. Even then, rivers must be forded in the morning when the waters are down since there are no bridges. You will feel completely alone and isolated en route — but only until you arrive.
Suddenly, the valley is teeming with campers, anglers, horseback riders, swimmers and hikers. Two old American school buses, painted dark olive green, form the central shop and café, and new lavatories, showers, picnic tables and barbecue pits serve the campers. The Iceland Touring Association maintains a mountain ‘hut’ for which accommodation can be booked; everything else is do it yourself.
The northern side of the valley is formed of a rhyolitic lava flow — an unusual occurrence in mainly basaltic Iceland — which erupted from nearby Mt Brennisteinsalda in 1480. Rhyolite has the highest silica content of all volcanic rocks, but unlike at Svartsengi, the rocks are not geothermically altered at depth by seawater so the silica is not released into the springs. Because silicic lava is so viscous, it flows slowly and builds up to double the thickness of basalt flows. Like so many other lava flows in Iceland, however, this one came to a sudden stop when it ran out of power and so towers 30-60 feet over the valley floor lying before it.
Hiking Through the Rhyolitic Lava Fields and a Hot Springs Soak After
A path northwestwards up a small tributary takes you between the looming green but barren flanks of Mt Bláhnúkur and the lava flow itself. The green colour is from chlorite, a weathering mineral of the high-silica volcanics. The path then begins to climb into the lava field itself, named Laugahraun, where high-water-content pitchstone is ubiquitous. Obsidian, a drier form of silica glass, is also present but hard to find.
At the top of the trail are geothermal vents: hot, hot, hot and sulphury. We’ll save our soaking for later. Winding down through the lava field, we come to another back valley lined with multicoloured rhyolitic mountains in shades of red and orange. A family of swans floats on a pool in a field of green. Onwards across the last stretch of lava and down the stream running along the base of the lava flow. Where the coldwater stream is joined by an outpouring of hot natural mineral water nestles the Local Peoples’ Hot Spring (Land+manna + laugar) for which the valley was named.
An open wooden staging area is provides for a quick change into swim togs (bathers used to go without, but alas…). Care is required walking over the chunky lava streambed under clear knee-deep water (photo) — better to wear flip-flops or crawl with one’s hands. Also, in contrast to the Blue Lagoon, the Landmannalaugar website noted a parasite infestation in the early 2000s — nothing but algae since then. Since the stream flows across the spring input, the water is constantly changing — and the temperature as well. Keep moving to find your hot spot, and enjoy!
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