Over new year my boyfriend and I flew out to Dubai to spend the last weeks of the vac with my parents (and also in the sun!). The ten days we spent out there were far from relaxed as both of us like to be busy doing things and there was not a day without an activity planned. One such of these activities was a hike through Wadi Showka in Ras Al Khaima, one of the seven Emirates of the UAE.
I first discovered this hiking trail after my mum brought me and my sister there for a hike last easter. The wadi starts off as a narrow, steep sided valley that is littered with deep pools between that are ideal for a quick dip but meant that last time we came we didn’t make it very far before the water meant blocked our path completely. So this time, hoping the pools were smaller as there had been less rain, I was determined to make it further.
A quick swim in one of the larger wadi pools
January is probably the most ideal time to hike in the UAE with temperatures only reaching about 20-25ºC at the peak of the midday heat. We drove for about an hour before hopping out the car, lathering on some sunscreen (especially vital for my pasty boyfriend who won’t get offended by this as the chances of him actually reading my blog are low), and setting off on the hike.
The start was lovely, when everyone stopped chattering (or mostly I stopped rambling about the how cool the rocks are) it was eerily silent. The only few sounds were the odd birds (which my mum identified as quite boringly a house sparrow) the breeze, and the trudge of our boots on the rock. Speaking of the rock, as that’s why you are reading this surely, they were amazing. Wadis are essentially dried up river beds in the desert, but in the winter months, when it rains high up in the mountains, massive flash floods occurs without warning. Water rushes down the valleys, bringing any rocks, boulders, and pebbles in it’s path with it, dumping them in the wadi. As the water stops flowing and dries up over the next few weeks smaller and smaller material is dropped as energy is lost. These events are spectacularly easy to see in the rock record and this particular wadi was littered with gorgeous flash flood deposits.
A flash flood deposit seen on the walls of the wadi, look at the different size rock clasts all mixed up together (unsorted) showing a high energy event/mass flow must have deposited them.
Evidence of water action in the area was also seen in cross beds of various sizes along the wadi walls. Cross beds provide evidence of water flowing. Just as air flowing forms sand dunes, which are preserved as decimetre size cross beds, water flowing forms various ripples (effectively small dunes) and other features that show up as cross beds on millimetre to centimetre scales. These are key diagnostic features in rocks in the field to tell if water has been there and which way it was flowing.
Some much finer laminations seen in the wadi showing a low energy period, probably during a drier season when the last of the water from the pools/flash floods was evaporating.
As we continued up the wadi (towards the ‘source’ if it were to be a river) it began to narrow and we came across the pool we swam in last time. The last rain in the area was probably a few weeks ago and the pools were still very deep. Yes, they were not the cleanest pools ever with an abundance of algae, frogs, and even small fish but they were still lovely enough for a quick cool down swim.. The prescence of the fish did confuse me, if the water is not there year round how do the fish get there? My proposal to my boyfriend of ‘they spawn there like sheep do in Minecraft’ is probably not the most scientific explanation but this is something I am yet to google so if anyone knows the answer please do let me know (a handy segue into a shameless self plug, follow me on twitter @LivAllen02).
Determined to get further up the wadi than last time, we clambered round the edge of the pools and after about 100m of difficult, spider man style, wall clinging climbs round the water the wadi widened and flattened to reveal a massive valley that was gorgeous to hike. The rocks then continued to impress (as expected). What I find really cool to see in person is the natural ‘cement’ you can see between the clasts in the flash flood deposits. Did I try to lick it to tell it’s composition? Yes of course, I’m a geologist after all. The result was 'it’s not halite' and that is about as far as my licking skills get me but I am thinking it is most likely gypsum based on what you would expect to find in a wadi. Gypsum, an evaporite mineral, tends to form in arid environments where water evaporates quickly.
Some of said cement forming holding together clasts of lots of different sizes.
After about an hour we began to ascend much steeper up to the peaks in the area. Climbing these was much more tricky than expected as the rocks are very loose under your feet and slip away very easily. In the desert, the extreme heat causes rocks to 'crack' as changes in temperature during the day vs the night mean the rocks expand and contract. This means that the rocks are very broken up and loose underfoot. We did however make it to the top, got some cute pictures and turned round to walk back.
A gorgeous view of the peaks looking down into the various wadis, and my boyfriend.
On our walk back we came across a blue headed lizard. It’s actually amazing how much wildlife there is in the desert when you look. Shrubby plants, and even some trees, thrive there, and birds, lizards, spiders, beetles, as well as frogs and fish in the pools also go about their lives as if they aren't in one of the world’s most hostile biomes, it really is very cool to see.
A pic of the blue headed lizard sitting on a rock taken by my mum who managed to get impressively close to it without scaring it away.
Going on hikes like these, be it in the UAE desert, the Scottish highlands, or just a round Oxford amazes me how much geology you can see around you everywhere. The beauty of the subject is that you see the things you learn in real life, and not just when you’re on a field trip. I remember the first hike I went on after my first term at Oxford and pointing out the cross beds int he rock to my dad, I was so proud of how the things I’d learnt in lectures I was just now seeing in a leisure pursuit. Rocks in real life are so interesting and Im very lucky to have grown up, and now get to visit, a place with such easy access to so much incredible rock formations and exposure!
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