Discover Argentina and Explore the Fossil and Dinosaurs of Ischigualasto
- Wayne Munday
- Oct 24, 2024
- 5 min read
Updated: 15 hours ago
The Ischigualasto-Villa Unión Basin in northwestern Argentina, spanning San Juan and La Rioja provinces, is one of the world’s most extraordinary geological and paleontological sites. Nicknamed the “Valley of the Moon” for its surreal lunar-like landscapes, this UNESCO World Heritage Site preserves an unparalleled record of the Late Triassic Period. Visitors can explore wind- and water-eroded formations such as El Hongo, The Sphinx, and El Submarino, alongside a remarkable fossil record of early dinosaurs and other tetrapods. Formed through tectonic rifting and sedimentary deposition, the basin provides crucial insight into the rise and diversification of dinosaurs during the Carnian Age. Beyond palaeontology, Argentina offers diverse ecosystems, from Patagonia glaciers to Iguazú Falls and the Iberá Wetlands, creating an unparalleled ecotourism destination.
In 2000 UNESCO designated the Ischigualasto and adjacent Talampaya Natural Parks as a natural World Heritage Site because of the areas importance in providing an invaluable land vertebrate faunachron known as the Ischigualastian LVF used to correspond the Late Triassic deposits worldwide for the origin of dinosaurs as well as other early tetrapod's including amphibians, reptiles, birds and mammals.
Before we explore the fossil record of the Ischigualasto-Villa Unión Basin its interesting to first note the otherworldly looking rock formations and topography of the Ischigualasto or “Valley of the Moon”. This landscape was formed by millions of years of wind and water erosion that has sculpted these colourful mineralised layers of rocks into bizarre natural sculptures with some notable landmark names like El Hongo (“The Mushroom”), The Sphinx and the El Submarino (“The Submarine”).
Argentina is a premier ecotourism and travel destination offering a raft of natural wonders to attract adventure seekers, nature lovers, and cultural enthusiasts from around the world though it is probably better known for its vast and varied landscapes than for its fossil record.
Argentina is a premier ecotourism and travel destination offering a raft of natural wonders to attract adventure seekers, nature lovers, and cultural enthusiasts from around the world though it is probably better known for its vast and varied landscapes than for its fossil record.
Argentina is a country of contrasts ranging from the icy and dramatic scenery of the Perito Moreno Glacier, the jagged peaks of Mount Fitz Roy, and the windswept plains of the Tierra del Fuego National Park. To the Pampas region a wide-open landscape of fertile plains of grassland known as the "heartland" of the country extending westward across central Argentina from the Atlantic coast to the Andean foothills. This is where Argentina’s traditional gauchos manage the herds of livestock and also where the Argentine asado or barbeque is very much a tradition.
An unmissable highlight of Argentina is Peninsula Valdés inscribed also as a UNESCO World Heritage site in 1999 for the conservation of marine mammals. It is home to an important breeding population of the large endangered southern right whale as well as important breeding populations of southern elephant seals and southern sea lions. The orcas in this part of the world area have developed a unique hunting strategy that involves them deliberately beaching themselves on the shoreline with speed and precision in their pursuit feed on sea lion pups.
Argentina also offers unique ecotourism experiences in its lesser-known regions such as the Iguazú Falls within the northern Iguazú National Park. The falls are one of the largest and among the most awe-inspiring waterfalls in the world located within the Atlantic Rainforest whose biodiversity of flora and fauna includes jaguars, howler monkeys, and toucans.
Also there is the Iberá Wetlands (Esteros del Iberá) in north east Argentina. This area is one of the most important freshwater ecosystems in South America, Argentina’s largest protected area and the worlds second largest freshwater wetland of lakes, floodplains, grassland and subtropical forest and home to over 4,000 species of animal and plants.
Then there is the Ischigualasto Provincial Park covering over 2,700 Km2 of desert close the border with Chile and in the El Monte rain shadow this UNESCO designation crosses both the San Juan and La Rioja Provinces on the western border of the Sierra Pampeanas of the Andes Mountains.
Of the six rock formations it's the Ischigualasto Formation from the Late Triassic Epoch that is our focus. The Ischigualasto Formation is a river deposit attributed to the Carnian Age (named after the Kärnten or Carinthia region of Austria) of the Late Triassic Epoch.
The Triassic Period is well known to have been bookended by two of the big-five extinction events. Between these extinction events Earth also experienced numerous climatic disruptions including the Carnian Pluvial Episode. It was this short episode during the Triassic Period around 232 million years ago that influenced the rise and diversification of dinosaurs and whose story is reflected in the Ischigualasto Formation.
The Carnian Age was a time when volcanic activity and tectonic rifting across Pangaea led to an intense and disruptive change in the climate. Both global warming from the release of greenhouse gases principally carbon dioxide from the Wrangellia Large Igneous Province of western Canada and an increase in rainfall created tropical conditions across the globe.
The shift from an arid climate to a tropical climate influenced the reshaping of ecosystems and triggered a growth in biodiversity both on land and in the seas. On land the availability of water meant that lakes and river system grew both in number and size and the rates of weathering and erosion increased released vast quantities of nutrients into the environment.
The availability of a favourable tropical climate and improvement in the accessible nutrients led to water loving plants and algae taking the ecological opportunity to diversify and radiate around the world. Whilst others that were more adapted to the previous arid conditions either became extinct or more specialised.
The increased availability of water and plant life encouraged evolutionary innovation by dinosaurs and this led to a rise of herbivorous dinosaurs feeding upon an abundance of plants and a rise in the number and diversity of their carnivorous predators. These early dinosaurs would continue to evolve and dominate terrestrial ecosystems for the next 160 million years.
The Ischigualasto Formation is known for its exceptionally well-preserved fossils of early tetrapod’s and dinosaurs. Of the most common tetrapod’s found in the Ischigualasto Formation are Rhyncosaurs, cynodonts, temnospondyls, dicynodonts and archosauriforms including the emergence of the dinosaur lineages including saurischians (Herrerasaurus, Eoraptor and Pisanosaurus mertii) and ornithischians (Venaticosuchus rusconii).
The fossils held within the Ischigualastian LVF helps to understand the early stages of dinosaur evolution beyond the first appearance of the ichnites or footprints of Dinosauromorpha found in Poland and Tanzania dated from the Early Triassic.
BEFORE YOU TRAVEL TO ARGENTINA
This information is for people travelling on a full ‘British citizen’ passport from the UK. It is based on the UK government’s understanding of Argentina’s current rules for the most common types of travel. The authorities in Argentina set and enforce entry rules. If you’re not sure how these requirements apply to you, contact the Argentine Consulate in the UK.
