One more step, the last before the top of the hill, followed by a little jump onto a flat block of outcrop, and I finally raised my eyes from the ground and looked around. I froze in awe, paralyzed, staring astonished at the desert all around me. In every direction I gazed, I could only see infinite immensity in warm colors. Not a single form of life, not a sound; only rocks, sky, and the calming but simultaneously slightly alarming sensation of being alone in a formidable vastness. I was on a dry, empty, Mars-like alien world.
We were travelling along an off-road track on our way to the Chandman Massif, the second target of our campaign in south-western Mongolia, when we stopped for lunch between two rocky hills emerging from the desert. A testament to widespread volcanic eruptions in the geological past, we had immediately approached these interesting outcrops. I had also taken the chance to climb up the hill: as you can tell from my opening paragraph, it was definitely worth it!
Besides our local guide and the four drivers, eleven of us had arrived in Mongolia to find evidence of the abiotic production and migration of hydrogen, methane, hydrogen sulfide and other gases and fluids within rocks. These gases represent a crucial energy source for organisms which do not rely on photosynthesis and can live in extreme environments where light and oxygen are very low or even absent: exactly the kinds of organisms that are thought to represent the very first forms of life on Earth. Our group was composed of geologists from the University of Bologna and the National Council for Research of Pisa and Turin, together with biologists from the University of Naples and a scientific journalist and photographer from Basel.
So why go to Mongolia? One of the massifs we were exploring in south-western Mongolia is described in literature as comprising very thin, undisturbed lithosphere that has been tilted almost 90 degrees and emplaced onto continental crust. Therefore, one can now traverse laterally on foot from the former crust-mantle boundary to the former crust surface over a short distance. The fluids we were looking for used to circulate within these rocks 500 million years ago, although we knew we could still find them trapped in tiny ‘fluid inclusions’ inside the rocks we were there to sample. These inclusions, together with other traces of fluid migration, provide clues that only geologists can distinguish and interpret. Our fieldwork brought us to unreal places: arid deserts, windy steppes, burning-hot dry valleys, cold mountain tops, grassy fields grazed by sheep and goats under the watchful eyes of fierce horsemen, and fascinating Buddhist monasteries.
The field campaign lasted from the 21st July to the 1st August, a very busy period that we spent exploring and sampling the Naran and Chandman Massifs in south-western Mongolia, between the Gobi Desert and the Altai Mountains. We searched principally for serpentinites and partially serpentinized peridotites, portions of Earth’s mantle transformed by water. We also collected other mafic and ultramafic rocks derived from ancient ocean crust, and carbonate and silicic rocks that were originally deposited on that ocean floor which have since reacted with other rocks during the processes that led to exhumation. Back in the Deep Carbon Lab, there will be plenty of work to do in order to analyse the more than 320 kg of rocks sampled, using microscopy and geochemistry techniques to search for decisive, unquestionable proof demonstrating fluid production and seepage.
From the top of that hill, during the short break in a long journey by our 4×4 cars, I was feeling like Matt Damon in ‘The Martian’: alone in a strange and hostile world. And that made me think even more on how life could arise from such a barren world as Earth was at the beginning: perhaps our work can add a little piece to solve that puzzle?
Thomas Gusmeo
(The expedition benefited from technical support from Vaude and Ferrino.)
Return to Stories and Expeditions.