The Geologists’ Nirvana of the Danakil Depression – PART 1

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Blog 50 by Tan: The Geologists’ Nirvana of the Danakil Depression – PART 1

 

The people who had previous expressed a keen interest in the geology tidbits offered up in this blog may come to regret such assertions. I am going to engage full geologist mode all up in this blog post as it seems only fitting for a report on the Danakil Depression, which would have to be one of the most unique geologic areas on the face of this great planet of ours. So prepare to be astounded or… mildly interested… or mind numbingly bored depending own your particular interests. I will try to limit geo-jargon and won’t be referencing anything as I am a civilian now and couldn’t be bothered. Suffice as to say everything I tell you about Danakil comes from the scientific exploits of many clever geologists before me.

 

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Stand Back

 

We had made the decision to spend a huge amount of money on a 4-day tour of Danakil Depression some time ago. Still it was hard to reconcile the fact that we long-term unemployed vagabonds were about to drop a hefty $US500 each on it. We rocked up to Mekele, the departure point for all these tours, in the hope that we could swing a bargain by getting in on a tour at the last minute. Chances were good that any tour departing in the off-season would have vacancies on it, though the chances were equally good that there would be no tours going at all. However we were lucky enough to stumble across a tour company with a tour leaving the very next morning and they were willing to give us an off-season rate of $US450 per person. Sorted.

Our timing of our foray into the Danakil Depression was far from ideal… in fact it was the worst possible season as we were there in the height of summer and Danakil is a hard enough place to endure in winter. With areas as low as 120m below sea level we could expect temperatures in the order of 50 degrees Celsius (or 122 Fahrenheit to those that way inclined). I believe a record high of 67 degrees C was once recorded there but never officially verified. I’m guessing because any witnesses promptly burst into flames.

 

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And some of what I say might even be right…but I make no guarantees

 

While both Mick and I have experienced such extremes temperatures on remote mine sites in Australia we had to confess that at times the mercury pushed 50 we would just sit in our air-conditioned offices, eating frozen popsicles and doing bugger all work. No such respite would be available to us on the Danakil trip as we would be camping, hiking and travelling vast distances in a car with an air conditioner that will invariably be bested by the Hades-like environment.

We had been dead keen to ride our bikes on the tour but knew it was a completely foolhardy option this time of year. Those are proper temperatures. Despite the easy terrain we knew we could never enjoy travelling in convoy with 2 slow moving 4WDs in such heat. So with a heavy heart we found a place to leave the bikes. And thank goodness we weren’t stubborn in our desire to ride, as the two 4WDs were intolerably slow and prone to bogging.

 

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Danakil Depression location map courtesy of the interwebs

 

A BIT OF AN INTRO TO THE DANIKIL DEPRESSION

The Danakil Depression is located in the Afar Region of north-east of Ethiopia near the borders of Eritrea and Djibouti. The famous British explorer Wilfred Thesiger described the place as ‘a land of death’, which is a perfectly apt description for any outsider entering the region. The local Afar population on the other hand have, over generations, adapted to the utterly ruthless environment and eek out a living as pastoralists and salt miners.

 

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The Afar are some tough people and rock some impressive traditional hairdos such as this. There is a popular myth that the Afar used to cut the testicles of their enemies and wear them around their necks. A bit extreme, when all you have to do is make a man watch enough Downton Abbey or ride a BMW and they will wither and fall off on their own account.

 

Danakil really is the epitome of a hostile environment where both nature and man can be… brutal. The area has been a hotbed of rebel movements both domestic and from the very nearby Eritrea and Djibouti. Add to this your run of the mill non-political banditry that occurs in this place where people are extremely poor and with ready access to serious weapons. Unfortunately tourists have been targets for each of these groups, primarily as a means of disrupting the tourist industry as a response to what they view as political marginalisation and economic exploitation of the Afar region by the Ethiopian government. Due to the history of tourist focused attacks and attempted kidnappings many governments list the Afar Triangle as a DO NOT travel locality. It is the kind of place you should NOT visit without official guides.

THE GEOLOGY OF DANIKIL – WHATS ALL THE FUSS ABOUT?

The Danakil Depression is a place of volcanoes, hot springs, fumaroles, faults, fissures, maars, hydrothermal pools, slat flats, sprawling basalt fields and generally bizarre land formations that make for a veritable geologic wonderland – paradise – heaven – nirvana, what-have-you.

What makes the Danakil truly unique in the world is its tectonic setting known as the Afar Triple Junction, which is the convergence of the East African Rift, the Gulf of Aden Rift and the Red Sea Rift and where the earths crust is being torn apart in three directions at a breakneck rate of 0.8 to 2cm per year.

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The Afar triple junction.

There are but two triple junctions that can be witnessed on land; Danakil and place called Hengill in Iceland. All others can be found on ocean floors around the planet far out of easy access to humans. Unlike the Hengill triple junction in Iceland, the Afar triple junction is the only one (on surface) where all 3 plates are moving away from each other (rift-rift-rift). At Hengill two plates are moving away from each other and slipping along the third (rift-rift-transform).

All this makes the Danakil area exceedingly special and the odds on bet as the site of the planet’s next major ocean as it transitions from a continental rift to an oceanic one. The spreading process of these divergent boundaries has already separated Saudi Arabia from the African landmass, forming the Red Sea. The separation of the easternmost corner of Africa is the next step in the areas tectonic evolution. Geologists estimate it will take a mere 10 million years (although some geologist estimate 100 million years – either way just a tiny ripple in time for rocks) until the rifting is complete to the point that the Red Sea and Indian Ocean inundate the area turning the Horn of Africa into a large island. Much Rad! How Geology! What Awesome!

 

Here is a link to a page with a great little animation of triple junctions evolution. When the continental crust (lithosphere) stretches beyond its limits, fissures begin to appear, magma rises and squeezes through the widening cracks, sometimes to erupt and form volcanoes and ultimately generates new crust where the plates diverge.

 

After meeting the four Spaniards that would be joining us on the tour we split into our respective 4WDs and hit the road. The day was spent cruising along pristine tar roads with little traffic to speak of. The farther we ventured the lower we got and the lower we got the hotter it became. Barren plains and mountains displaying spectacular tilted bedding had us recalling fond memories from our times in Kaokoland, Namibia where we saw the impressive folded bedding of the Ugab River Valley.

 

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Not far out of Mekele.

 

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People used to pay me to do this.

 

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Views that had us pining for Namibia once more

 

We stopped for lunch in small town of Berhale, which is the centre of the salt trade in the Danakil Depression. Berhale is the traditional drop off point for the salt caravans transporting salt bricks from Danakil’s salt mines prior to transportation (these days by road) to the city of Mekele. Salt mining takes place 10 months of the year with a 2 month break at the height of summer when the conditions are just too punishing on man and beast.

 

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Afar habitations on the way to Berhale.

 

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The camel trains of the Danakil. It is estimated that more than 1 million camels per year do the trek from the mines to Berhale. Wish I took this shot but it was someone else on the internet

 

It was a shame we missed out on seeing the ‘white gold’ trade in action. In the seemingly pervasive theme of this trip of ours, the modern world is encroaching and is set to overwhelm the traditional way of life in the area. The smooth tar roads we just travelled along will be the nail in the coffin of the millennia old practice of salt mining. With the roads in place, modern commercial salt companies requiring only a modest labour force due to their mechanised extraction techniques will inevitably enter the fray and crush the traditional salt mining trade. If you want to see Danakil, I’d advise doing it sooner rather than later, because when that happens the proud and traditionally armed to the pointy teeth Afar, will likely not take the changes well. The Afar have furiously guarded their salt resources for centuries and will hardly stop now, particularly when there remains no alternative livelihood.

 

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Salt mining. Also some other clever bugger’s photo

 

After a simple yet tasty lunch followed by ice cold soft drinks we were back in the cars and on the road again, this time on our way to the salt mining hub of Lake Assala.

 

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Apart from the new tar roads (build to service Israeli and Canadian potash mining operations) the towns had very little in the way of amenities.

 

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Our restaurant wasn’t much to look at but the food hit the spot.

 

After picking up a few compulsory military personnel with AK47s to guard us during our next excursion we headed along salt roads to the nearby salt plains. Some areas of the Danakil Basin are said to have between 2.5 and 5km thick salt layers deposited over millions of years while the area was connected to the Red Sea during periodic sea transgressions and flooding events. The estimated date of the most recent sea transgression into the Danakil basin is around 30,000 years ago.

After goofing around on the saltpans for a bit it was back to tiny little hamlet of Hamed Ela for the night. Hamed Ela is a located 92m below sea level and is bit of a miserable sight. It is dry, dusty, rocky and littered with countless water bottles from the steady stream of tourist groups that come through. We found a bucket of non-saline water to bathe in (hard to get around these parts) before having a great dinner despite the Spartan surrounds.

 

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Sunset over the saltpans

 

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Goofing off on the salt pans

 

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Tours traditionally stop at this place for a dip. These waters are of higher salinity than even the Dead Sea.

 

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A couple of the others got it but we passed.

 

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There was plenty of land that looked like this.

 

Sleep was near impossible to come by that night due to the heat. Mick and I are used to heat and world-class sleepers but our skills were rendered inadequate given the conditions. It was still 40 degrees when we went to bed about 11pm and only dropped to a minimum of 38C in the early morning. We were sleeping on raised cane beds out in the open but there was little respite from the suffocating heat as we tossed and turned and periodically doused ourselves with water. As the Afar people are predominantly Muslim we went to efforts to cover up to the extent that our bodies could tolerate. But all that went out the window that night as one piece of clothing after another was jettisoned until we were all sprawled out in our underwear being culturally inappropriate in public and struggling to care.

 

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Hamed Ela – It is from this ramshackle collection of huts that 5 tourists were kidnapped in 2007 and held for a fortnight. Luckily they were all returned unharmed.

 

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Our lodgings for the night. The bathroom is wherever you make it and a toilet visit required a decent hike to have any semblance of privacy… and even then…

 

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Mick chilling as well as he could in a desert 92m below sea level.

 

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The architecture, though not much to look at, was a great way to get shade and let the air circulate. In the background you can see a building that could only belong to the nearby Potash mining operation.

 

Fortunately when we woke the next morning there was no one in sight to witness our debauched public sleeping. After a few hours of broken sleep we were up having breakfast in the dark, and on the road before 6am in order to visit Dallol volcano and its psychedelic hot springs. The Dallol area is located 120m below sea level and subsequently experiences ridiculously high daytime temperatures. And there was no question of going to Dallol in the middle of the day. By 7am the temperature was already 48 degrees and would soon rise to over 50.

 

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It is only the die-hard salt miners that operate this time of year. We drove past this lone train of camels heading out to the salt mines. I had to wonder what it was that pushed these guys to make the trip when no one else was… when both they and their camels would be utterly punished by the conditions…

 

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Tepee structures – formed by the dilation of surficial beds or shrinking of underlying sediments, when laterally confined material cannot expand they rear up under compression like this.

 

The landscape to the volcano consisted of flat saltpans extending off into forever. While travelling along the salt roads we couldn’t help but imagine ourselves on our bikes absolutely fanging it. It was odd and frustrating to find ourselves moving at a snails pace over minor washouts we wouldn’t have bothered to even slow down for on the bikes. The blessed air-conditioned cab on the other hand was a welcome consolation for inferior 4-wheeled mode of travel.

 

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Cars parked at the base of Dallol’s updomed salt structure. You may not be able to tell from the photo but it rises 50-60 m above the salt plains.

An oppressive heat consumed us as soon as we got out of the car. Despite the monotonous landscape the appearance of the Dallol volcano is decidedly subtle. Dallol is a pretty unique type of volcano in that it is not actually a volcanic cone but a dome (anticlinal) that rises from the extensive salt plains at a gentle gradient caused by the intrusion of a magma body that is the heat source for the geothermal system. Gravity and magnetic airborne surveys indicate an anomaly (most likely the igneous intrusion in question) at a depth of around 1km. Geologists aren’t sure of the date of the updoming and formation of the Dallol volcanic system but surmise that it occurred after the last major sea incursion that formed the salt layers some 30,000 years ago. Because after all, you can’t deform sediments before they are deposited – and there you have it! The essence of geology – logic and inference… and lots of guessing… and a bit of the science… but mostly guessing.

 

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Yeah… so this is true

 

Dallol itself is essentially an explosion crater caused by a huge phreatic eruption. A phreatic eruption is one that occurs when a high temperature heat source contacts and heats groundwater to the point of boiling, resulting in an explosive plume of rocks, ash, water and steam. These types of eruptions are hard to predict in that all it takes is a fissure/crack to open in a system like Dallol through shifting magma below or a minor earthquake (Danakil is very seismically active). It just takes a blast of heat escaping the fissure and groundwater to enter the crack and turn to steam. As steam occupies greater volume than water it expands in all directions and causes a violent explosion of pulverised rock, heat and steam. Back in 2014 there was a phreatic eruption of Mount Ontake in Japan that killed 36 people. Japan’s volcanoes (including Ontake) are rigged up with a mass of sophisticated monitoring equipment and while they can predict the deeper level activity, shallow steam eruptions like the ones that take place at Dallol are basically impossible to predict. So be sure to wear your lucky underwear should you visit.

 

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Salt mushroom structure from a no longer active hydrothermal pool. These are named for the obvious resemblance to mushrooms. These bad boys can be as large as half a metre in diameter. They usually form after periods of intense evaporation when the shallow pools become covered with a thin, delicate layer of floating halite crystals. Some crystals sink to the bottom of the pool and accumulate enough to form stalagmites (like a stem of halite crystals going upwards) which reach the surface. At this point, floating halite crystals accrue as concentric rings of halite and adhere to the stalagmitic stem.

The most significant eruption at Dallol occurred in 1926 but there has been some interesting activity in recent history. In January 2011 an ash plume was observed rising from the Dallol crater. Then in very exciting news, on January 2, 2015 (just 6 months before our visit) it is reported that an ash plume and nighttime incandescence was observed above Dallol which would make it the first magmatic eruption (phreato-magmatic eruption is the precise term for a steam blast eruption with extruded magma in the form of volcanic bombs). I didn’t notice any signs of extruded volcanic material and haven’t been able to see that the event got confirmed but if it did in fact happen it would be the first time magmatic activity has occurred at Dallol which is a pretty big deal. Suffice as to stay that the system is still very much active.

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Old salt pillars. Compare this to the active pools and you’ll see how the surface features of the hydrothermal system have moved over time.

But what really makes Dallol worth writing home about is its surface manifestation – the assault on the senses, iridescent wonder of the Dallol hot springs. It has to be one of the most vibrantly colourful natural landscapes on the planet – like looking through a kaleidoscope while on an acid trip. And it all thanks to the relationship between Dallol’s heat source and the thick succession of overlying salt deposits.

 

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Why things are so at Dallol

 

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The colours on display at Dallol are dictated by the height of the water table. Colours change from light (whites and yellows) to darker reddish hues when water level drops and can go on then return to its previous colours when the water table rises again. Here we are in a section above the current water table.

 

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You should therefore avoid walking through any of the white, green yellow areas as much as you can. There is a definite risk of finding yourself ankle deep in highly acidic boiling fluid.

 

DSCF4734The lurid colours of the hot springs are due to an orgy of halite, calcite, sulfur hematite, iron, sodalite, fluorine, potassium salts, mud and halophile algae and a whole lot more.

 

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Dallol is an uplift feature topped by a phreatic crater full of hydrothermal karst structures.

 

DSCF4770 A geologist – out standing in her field (see what I did there?)

 

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DSCF4774The pools are very high salinity and range from moderately to extremely acidic. NO TOUCHING!

 

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DSCF4792Terraced acid lake with salt deposition.

 

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Our Afar guide sitting on a domal structure full of gas pipes.

 

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Some of the delicate salt formations you can find in these gas pipes/fumaroles. I’ve read that measurements have been taken of the amount of gas that emanates from these fumeroles and it is said to be negligible….even so I wouldn’t stick your face in there.

 

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Delicate little salt balloons

 

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Salt balloons and salt flowers

 

The hot springs occur within a subsidence structure of a phreatic eruption crater. The springs are formed by the groundwater heated by Dallol volcano’s magma source rising through the deep successions of evaporite deposits. As it does so the groundwater becomes a supersaturated, supersaline brine incorporating different minerals on its rise to the surface where it eventually emerges through hot springs. As the brine evaporates, salts are precipitated to form a variety of salt formations including salt pillars, salt terraces and geothermal pools.

 

DSCF4759 Due to the minimal levels of dissolution and erosion in the crater it is estimated the hydrothermal pools are perhaps only hundreds of years old which is embryonic in geological time… 100 million years is positively youthful in rock terms. The underground manifestation of the system is most likely considerably older.

 

Dallol isn’t the safest places to spend a lot of time. There are no pathways to follow and the ever-changing environment can leave you walking on a salt crust of unknown thickness over up to 110°C (the water can be saturated with various salts don’t forget), highly acidic fluid (the geo-chemistry is highly complex). There is also the additional hazard of gases to worry about… and eruptions aren’t out of the question – you’d have to be pretty unlucky though. My advice when near the geothermally active areas; wear closed in shoes and watch your step, don’t touch anything wet and/or colourful, and keep your face away from holes or fissures (fumaroles – they can emit hot gases).

 

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Salt pillars form from a small central upflow point where halide precipitates on emergence at the top of the pillar. Pillars are also found in the more intense geothermal activity.

 

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Returning to the cars. We would only spend a couple hours this deep in the depression as the heat formidable

 

Next we made our way to check out the nearby salt canyons where uplifted layers of salt deposits have been eroded away to form towering pillars of up to 40m tall. We did a hike for as long as we could tolerate the heat. By now we were all red and completely saturated in our own juices as our bodies strained to cool down. It was amazing to see how our non-acclimatised bodies were coping with the conditions compared to the local Afar guide. The tour guides and drivers from the highlands were struggling as much as us, while the local Afar guide, skinny as a rake, didn’t even have a bead of sweat on him. I did notice however that by the time we were done with the hike he had only the beginnings of a sheen of moisture developing on his skin. Makes sense for people living in a place like this – with water so hard to come by, sweating is a luxury they could ill afford.

 

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The towers and pinnacles were eroded by wind and seasonal flooding.

 

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The rocks are composed mostly of salts of potassium and magnesium, interspaced with layers of soil.

 

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The banding is the result of clay and soil deposition from seasonal flooding in the highlands.

 

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Potassium rich brine pools. These are just a mixture of groundwater and geothermal upflow so not boiling and not acidic like at Dallol. Here the military guards are lathering themselves as they thought it was medicinal and good for the skin. Considering the number of dead birds around the pool I’m not sure how they came to this conclusion.

 

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But the military personnel were convinced the water was good for the skin so got lathered up. Incidentally, if you look to the top right of the photo you can see how high the pool levels had been in the past.

 

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Our skinny as a rake Afar guide to Dallol. The dead bird carcasses strewn around the pool seems to conflict somewhat with military guys’ assessment on the water.

 

After a prudently short time visiting Dallol we hopped back in the car and headed along the near roads to a small village possibly called Abaala. Abaala is traditionally the place where the Danakil tours spend a night in relative comfort in between the two nights spent in discomfort near the Dallol and Etra Ale volcanoes. The night’s accommodation was at a family homestay at a much more tolerable altitude.

The homestay family included a teenage girl who spoke English very well and surprised us greatly when she told us she spoke basically fluent Korean. Not at all something you would expect from a young Muslim girl living in a tiny village in the Danakil Depression. Her impressive skill was borne from her love of Korean soap operas and a lot of commitment and I was more than a little impressed.

 

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The Korean speaking girl in question. It was here dream to make it to Korea to study. Lucky for her a Korean animator met her during a Danakil tour. He is currently making a computer animation short about a young Muslim girl in the Danakil Depression teaching herself Korean from her much loved Korean soap operas. Gotta admit it’s a great premise.

 

While we were resting inside we noticed the Spaniards had been out playing with neighbourhood children who were extremely grubby. A couple of the kids had conjunctivitis dripping down their faces, a multitude of skin infections and there was a heck of a lot of determined hair scratching going on. The Spaniard’s were busy twirling the kids around, playing hand games and taking selfies. I have no doubt we must have looked like the most anti-social, jaded sad sack travellers by not taking part in the close quarters merriment.

 

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And here she is putting on a coffee ceremony for us.

 

We pointed out to them some of the highly contagious maladies that they were likely to be sporting themselves if they weren’t careful. They were horrified to learn that conjunctivitis is the result of getting feces or the secretions of pink eye in your eyes. And that ended playtime for the day. They resolutely followed our advice to not touch their faces until they’d washed their arms and hands properly. However it proved to be advice too late in coming for one of the guys, which we’ll get to shortly.

We decided it was time to track down some cold drinks so the Korean speaking girl from the homestay came along and with us so that she could protect us from kids throwing stones. Two of the Spaniards had already been hit by a couple rocks thrown by local riff-raff, and to their credit, were taking it in their stride. Mick was so used to us being moving targets that he knew counter intimidation was required. We had a clean run after he picked up a rock and kept tossing it up and down in his hand the whole way to the bar. Worked like a charm.

After a relaxed evening and a good feed we eagerly crawled into bed. The most exciting and physically taxing part of the tour was yet to come.

6 Comments on “The Geologists’ Nirvana of the Danakil Depression – PART 1

  1. Now I am even more pissed off that we missed it. At the time a German tourist got hurt there and all the tours there were stopped.
    Thanks at least your article is a damn fine comprehensive post, and makes up for what we missed.

  2. Hi to you both from Cape Town, great to read of your super account and take in the great pics, both of which bring back wonderful memories. These have also been re-kindled for us with all the work involved in publishing a book of our trip and editing up the 2 hour video which will go along with the it. T4A has very generously offered to market it via their network.

    Our next (possible?) venture is to go sailing, if that doesn’t prove to be financial suicide. I am currently doing the skipper’s course training required and, if and as we get closer to the actuality, Karin will follow suit.

    We wonder where you are now and wish you both very well,

    Pete

    • Awesome guys! Best of luck with the book/vid project and the sailing!!!

  3. Hi,
    Check out my paper at:
    link.springer.com/content/pdf/10.1186%2Fs13617-015-0042-x.pdf

    The dead birds at the thermal spring called Gaet’ale were killed by carbon dioxide eruptions, which could potentially be harmful to humans!

    Sharad Master

  4. Fantastic update guys, very very pissed also that we missed it during our round Africa trip; perhaps an incentive to go back? Friendly regards from Romania!

    Ana + John

    • Wow! Fantastic to hear from you guys. We have read your RR on ADVRider from start to finish a number of times. It is an absolute stand out report. Danikil is definitely worth visiting and would encourage anyone to go there if they could. But as for doing a bike trip through Ethiopia based on our experience I probably couldn’t recommend it. How Ethiopia itself can be visited quite easily without personal transport. There are some good bus services and flights between the main tourist town are very much affordable. Looking forward to sharing with you guys our experience crossing DRC.

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