Photographer's Note

Dallol: walking on sulfur formation in an acid lake

As the groundwater level is fluctuating the acid lake is moving up and down. In some case you can cross the acid lake (H2SO4) by walking on sulfur and salt deposits. Amazing and fascinating experience. Of course you have to watch our step!

If you plan to go there one day you must have an ware a gas mask (ABEK cartinge) as airborne toxic materials can be really toxic (sulfur gas) and unbearable to breeze. You will also need additional filters as gas masks have a limited useful lifespan that is related to the absorbent capacity of the filter.

Numerous phreatic explosion craters dot the Salt Plain NNE of the Erta Ale Range in one of the lowest areas of the desolate Danakil depression. These craters mark Earth's lowest known subaerial volcanic vents. The most recent of these craters, Dallol, lies 48 m below sea level and was formed during an eruption in 1926. Colorful hot brine springs are found in the Dallol area.

Dallol volcano is located in the Danakil Depression in NE Ethiopia, in a remote area subject to the highest average temperatures on the planet.

The volcano encompasses Dallol mountain (which rises 50-60m above the surrounding salt plains and has approximate dimensions of 1.5 x 3 km) and several other features in the vicinity, such as the 1926 crater near the "Black Mountain" about 1.5 km to the SW. Dallol is nested on top of an at least 1000m thick layer of quaternary evaporates including large potash (potassium salt) reserves.

Dallol mountain is thought to have been formed as the result of intrusion of a basaltic magma body underneath. The circular depression near the center of Dallol mountain is presumably a collapse crater, although neither its age nor the exact process from which it resulted are known. The SW flank of Dallol mountain harbours impressive salt canyons formed by erosion processes.

Picture published in DETAY M. — Le Dallol revisité : entre explosion phréatomagmatique, rifting intracontinental, manifestations hydrothermales et halocinèse, in LAVE, revue de l’association de volcanologie européenne, 151, 7-19 (2011).

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Additional Photos by Michel Detay (mdetay) Gold Star Critiquer/Gold Note Writer [C: 485 W: 1 N: 1034] (4895)
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