• DESCRIPTION

The Argentine Northwest comprises very distinct biomes, or geographical and climatic regions. From west to east they are: · The Altiplano or "Puna" · High Mountains of the Andes · Fertile valleys · Red-rock canyons and mountain passes · Humid Sub-Andean Sierras · Tropical jungles or Yungas · And the ecotone—or transitional zone—between the Yungas and the Chaco region. Besides the Yungas jungle on the eastern fringe of the region, the only fertile lands are those near the river basins, which have been irrigated extensively. Across millennia the erosive forces of these rivers has gradually created a multitude of red-rock canyons, such as the Quebrada de Humahuaca and the Valles Calchaquíes. West of these valleys the peaks of the Andes reach heights of over 6,000 metres (20,000 ft) and the Altiplano, an extensive 3,500-meter high plateau, dominates the landscape and continues far north into Bolivia and Southern Peru.