The Maras Salt Mines (Salineras de Maras) are located in the Urubamba Province in the Sacred Valley, at an altitude of about 3,200 meters (10,500 feet). It is an incredible terraced landscape located 50 kilometers northeast of Cusco, Peru. Featuring over 3,000 active salt evaporation ponds carved into a mountainside, the site dates back to pre-Inca times and is still traditionally harvested by local families.
Water from a natural underground hyper-saline spring is channeled into thousands of individual terraced pools. As the high-altitude Andean sun evaporates the water, beautiful white and pink mineral salt crystals are left behind to be manually harvested. Maras pink salt is highly prized by chefs globally for its unique flavor profile and high mineral content.
When we arrived it had rained a day or two previously. As a result the terraces looked like indented patches in the landscape with white patches.
We moved on to Moray (Quechua) an archaeological site approximately 50 kilometres (31 mi) northwest of Cusco on a high plateau at about 3,500 metres (11,500 ft) and just west of the village of Maras. The site contains Inca ruins, mostly consisting of several terraced circular depressions, the largest of which is approximately 30 m (98 ft) deep. As with many other Inca sites, it also has an irrigation system.
The purpose of these depressions is uncertain, but their depth, design, and orientation with respect to wind and sun creates a temperature difference of as much as 15°C (25 °F) between the top and the bottom.
Closed depressions such as these can trap cold air, particularly on calm cloudless nights at altitude. Heat in the form of long-wave radiation is free to escape skyward and cold air is heavier than warmer air, so it flows downslope. In most landscapes the cooler air drains into the valleys creating down-canyon winds at night and leaving the higher slopes a few degrees warmer.
This pattern is called an inversion because the typical pattern of air cooling as elevation increases is inverted. If air can flow into a closed basin, the capture of cold air is accentuated. Warmer air is displaced from the basin leaving the cold air trapped under a stable inversion. Temperatures in the basins can be several degrees cooler than the surrounding lands and remain colder until strong winds flush the cold air out.
By being colder, the basins can simulate agriculture that is several thousand feet higher in elevation. Air at the bottom of the basin is typically colder that the air higher up, so the test altitude can be adjusted by moving the plantings a few feet up or down the slope. In this way, the basins at Moray permit crop testing at this single site, by a consistent group of scientists thus providing much better control for their tests than spreading their tests to distant locations.
This landmark is widely believed to have been used for farming, and soil samples have shown that soils were brought in from different regions to be used in helping grow crops at the different levels of the terraces. The wide temperature differences in the terraces have created microclimates, similar to what is achieved in greenhouses in modern times. The landmark also looks similar to an open pit mine. After the mining was done, the Incas could have reinforced the walls to prevent landslides and started to grow crops on the terraces.
