2012. Hungarian Atacama Climate Monitoring Expdition

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The 2012 field season was completed according to our plans and was a complete success. The main aim of this expedition was to establish the basis, mostly by installing instruments, for our long-term monitoring work.

Permafrost analysis

  • The representative sites for permafrost monitoring were chosen.
  • The background of the long-term monitoring is established based on the first stage of measurements (Feb.2012 - Feb.2014). To achieve this, temperature measuring instruments were installed in every typical geomorphological altitude range.
  • As the most interesting aspect of the permafrost is its active layer, this is in the focus of our investigations. Therefore, instruments measuring in every 30 minutes were installed at multiple depths in the regolith: at 4200 m a.s.l. (10 and 35 cm in depth), at 5260 m a.s.l. (10, 35 and 60 cm in depth), at 5830 m a.s.l. (10, 35 and 60 cm in depth), at 6750 m a.s.l. (10 and 17 cm in depth), at 6893 m a.s.l. in two points at the surface and 10 cm in depth (+ a moisture meter on the surface).
  • With this instrument network we have initiated the highest permafrost monitoring mission in the world.
  • The bulk of these instruments are on the northern slopes of the Ojos del Salado. However, several instruments were placed at the neighbouring polygonal desert near the Laguna Negro Francisco (this constitutes the 4200 m a.s.l. altitude level).
  • Besides installing the instruments, during the field excursions we have mapped high altitude periglacial phenomena and the presence of buried ice.

The role of the wind

We have intensively investigated the signs of wind erosion and accumulation in the desert. This site is one of the highest and most arid deserts and tundra in the world, therefore the role of wind in landform development is prominent. We have inferred the following:

  • The micro and meso landforms were formed predominantly by the wind between the altitudes of 4600 m and 6300 m.
  • Similar sand ripples were found here, below 5500 m a.s.l., to the largest sand ripples (megaripples) of the world which were described from the Argentine side of the Pune de Atacama. They mainly consist low density piroclastit, in this case ingnimbrite which is a piroclastic rock with high vesicular volcanic glass content.
  • We have described several different types of megaripples along with their structures.
  • At 5200-5500 m the extremely strong wind transports big chunks, 2-4 cm in diameter, of high density volcanic debris on the windward side of the ripples, making them inactive.
  • Above 5200 m every bedrock cliff or bigger boulder is attacked by wind erosion, western sides are especially damaged.
  • On the slopes of old solidified lava flows, lee-side dunes are formed from coarse debris.
  • The surface damages of the pebble pavements, caused by the erosion, are restored by the wind transported sediments over a couple of years.

High altitude lakes and their life system

As the highest lake basins could be found on the Ojos del Salado, investigating them is an important aim of our expeditions.

  • The known lake basin at 6380 m, which holds shallow transient lakes, and another freshly investigated closed basin at 6500 m were filled with snow.
  •  These basins, which are 100 – 200 m in diameter, could hold transient lakes. The frozen ice in the regolith hampers the leaking of the meltwater and at the same time contributes to the meltwater amount in the basin as well.
  • A side crater at 6500 m, which also contains fumaroles, is the location of the highest assumed lake basin. We have observed that liquid water was flowing into the basin during our field activity and the snow seemed to became saturated with water. However, these observations were made by looking down from the summit, which is quite far from the bottom of this basin.