Ischigualasto, Where the First Dinosaurs Walked
In a desert valley of western Argentina, strange rock shapes stand in a moonlike landscape, and in its rocks lie some of the oldest dinosaurs ever found.
What was reported
Ischigualasto, often called the Valley of the Moon, is a desert park in San Juan province, Argentina. Its eroded rocks form strange shapes, such as a giant 'mushroom', a 'submarine' and fields of round stone balls, set against red cliffs.
Its rocks, from the Triassic period, have yielded fossils of some of the earliest dinosaurs known, including Eoraptor and Herrerasaurus, from about 230 million years ago, when dinosaurs were just beginning.
Explanations offered
The landscape was formed by layers of sediment laid down in an ancient river basin and then worn away. The stone balls are concretions, hard lumps that erode out of softer rock. It's a UNESCO World Heritage Site.
- When
- Rocks about 230 million years old
- Where
- Ischigualasto, San Juan, Argentina
- Witnesses
- Palaeontologists and visitors
- Status
- Confirmed
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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