In the tenth of a series of reports contributed by Cambridge researchers, PhD student Robert Hird pitches his tent next to a gas crater in Turkmenistan in the course of his studies on the stability of saline soils.
...I spent most of the time at the crater’s edge, mesmerised by the hissing flames emitted from tiny fissures scattered around the crater’s base and occasional blasts of hot air as the wind changed direction."
I was surprised to find that the road north was paved, surrounded as it was by a barren, gently undulating landscape of scrub and sand. A railway line ran parallel but was a poor travel option. Infrequent trains moved only slowly, on tracks rumoured to be laid without proper foundations. I was travelling with a local driver and a Turkmen guide towards the ancient city of Konye Urgench in search of inland saline soil deposits.
The bleak and unforgiving landscape was a stark contrast to the gleaming white metropolis of Ashgabat, the capital city of Turkmenistan, from which I had set out from earlier in the day. Ashgabat is a relatively young modern city with many public buildings and mosques clad in imported Italian marble but intertwined with relics of its former history under the Soviet Union. The streets are laid out as tree-lined boulevards with air-conditioned bus stops, chrome-plated traffic lights and small wooded parks containing statues of Lenin and Pushkin, a far cry from the emptiness of the Kara Kum or ’Black Sands’ desert through which we now drove.
I was in Turkmenistan on a reconnaissance mission to locate sampling sites for inland saline deposits known as playa, or locally as tugai. The Kara Kum desert, which dominates most of the country, has average annual temperatures between-10°C and 40°C and little (if any) rainfall. Its arid conditions influence the evaporation of groundwater, a process that deposits distinctive layers of natural minerals within its soils. The mechanical properties of saline soils are not well known, but it’s clear that their physical effects can be disastrous for infrastructure placed on and within such soils - occasionally leading to the destabilisation of buildings. Moreover, the stability of these soils is highly sensitive to environmental change. My work, which aims to understand the link between saline soil structure and destabilisation, depends heavily on characterising extremely mineral-rich soil environments such as those found in the Kara Kum desert.