Ces deux parcs contigus s'étendent sur plus de 275 300 ha dans la région désertique jouxtant à l'ouest les Sierras Pampeanas du centre de l'Argentine. Ils renferment l'ensemble continental le plus complet au monde de fossiles de la période du Trias (de -245 à -208 millions d'années). On y trouve six formations géologiques contenant des fossiles d'un large spectre d'ancêtres de mammifères, de dinosaures et de plantes, qui témoignent de l'évolution des vertébrés et de la nature des paléo-environnements de la période du Trias.
Parcs naturels d’Ischigualasto / Talampaya
© Philipp Schinz
Critère (viii): Le site contient une séquence complète de sédiments continentaux fossilifères représentant l’histoire géologique de la période du Trias dans son entité (45 millions d’années). Aucun autre endroit sur Terre n’a de gisements fossilifères comparables à ceux d’Ischigualasto-Talampaya qui témoignent de l’évolution de la vie vertébrée et de la nature des paléo-environnements du Trias.
[Uniquement en anglais]
Talampaya National Park and the contiguous Ischigualasto Provincial Park straddle the border between the provinces of San Juan and La Rioja in north-western Argentina.
The Ischigualasto-Talampaya region is a desert area forming the western border of the Sierras Pampeanas of central Argentina.
The nominated site constitutes almost the entire sedimentary basin known as the Ischigualasto-Villa Union Triassic basin. It was formed by layers of continental sediments deposited by rivers, lakes and swamps over the entire Triassic period (245-208 million years ago). The sediments contain fossils of a wide range of plants and animals including the ancestors of mammals and dinosaurs. They constitute the world's most complete continental fossil record known from the Triassic, revealing the evolution of vertebrates as well as the environments they lived in during this period.
Some 56 genera of fossil vertebrates have been recorded from the area, including fish, amphibians, and a great variety of reptiles including the direct ancestors of mammals. Most of the fossils are found in the uppermost levels of the geological formations and consist almost entirely of archosaurs, including large herbivorous and carnivorous species, primitive crocodiles and primitive mammals about the size of a rat.
The river deposits include large areas of flood plains which indicate rapid flooding, probably after monsoon type storms. Lake and swamp deposits contain large amount of fossil plants, some of them forming coal seams and others preserved as mummification of actual species, an extremely rare form of preservation known from very few localities. Six geologic formations make up the Triassic basin, the earliest of which are the Talampaya and Tarjados formations, red sandstone that forms the impressive cliffs of the Talampaya National Park. The remaining formations are composed of lake beds, swamps, river channels and flood plain deposits. These formations contain the abundant vertebrate and flora fossils.
Today Ischigualasto-Talampaya has sparse desert vegetation characterized by xeric shrubs and cactus. The fauna is typical of the arid regions of western Argentina including several species regarded as being of special value because they are either endemic, nationally threatened or culturally valuable, including Andean condor, chestnut canastero, sandy gallito, puma, guanaco, mara and viscacha.
Before the Spanish conquest, the area was inhabited by several groups of aborigines, usually semi-nomadic hunters and gatherers. The cultural value of Ischigualasto-Talampaya is of great significance, even though a detailed study of rock art, artefacts and archaeological sites has only recently begun. The site lies on the southernmost area of late Inca influence. At Talampaya, many sites have been unearthed and are easily accessible. At Ischigualasto, six sites of rock art have been discovered. In addition, cave and rock overhang habitation sites, as well as burial sites, campgrounds and tool-making areas have also been found. It is possible to classify much of the rock art in terms of geometric figures, human figures and combined scenes. Source : UNESCO/CLT/WHC