Dinosaurs Footprints

    Dinosaurs inhabited on Earth approximately 120 million years ago. How come we still observe their footprints?
    We all have had the experience of walking along the sea and see how the footprints we are printing on the sand disappear as the new wave comes.
    Why, then, some of the footprints left by dinosaurs are still observable?
    Let us imagine one of these dinosaurs walking on a muddy land, its weight would be leaving a track. Many of these footprints would disappear due to the effect of water or the accumulation of the same kind of mud.
    In other prints, mud would get harder as it dries becoming resistant to erosion and , as time goes by, the print will be covered by a new lay of sediments producing a natural copyof the print.
    As time goes by, these different kinds of dust become different rocks and give way to the fossil print called icnitae or footprints.
    If the material where the animal left the print is harder than the filling -in, we will observe the prints sunken as the ones we leave when walking. But if the opposite happens, the covering stratum may show a negative image.
    In spite of this, this process is neither simple nor frequent.
    In the surroundings of Chocón and Picún Leufú, abundant prints of a great variety of dinosaurs were found. They were all in very good condidions. These facts make the area a privileged one around the world.
    The dinosaurs ,whose footprints were preserved in the surroundings of Exequiel Ramos Mexia Lake, lived 105 million years ago. The Gigantosaurus Carolinii, weighing ten tons , is considered one of the biggest carnivorous dinosaurs ever found- its 15 meters lengh, its 1.65 meters dorsal vertebrae and its 22cm long teeth give evidence of this.

The study of a footprint can tell us if the dinosaur was big or small , if it was biped or quadruped as well as the number of toes or fingers they had. We can also know about the way they moved and the speed in which they did it - ordinary pace, running, jumping, etcetera.
In those far-distant times, the area of EL Chocón and Picún Leufú was a relatively plain zone in which there were shallow but big lagoons linked by rivers with slow current.

    The climate, hot and humid with dry seasons and probably subtropical, gave the landscape a quite different appearance from the desert that you can observe nowadays.
    In the borders, there was a varied and numerous fauna of dinosaurs, crocodiles, turtles and toads that may have lived permanently in the area.
    The feet of the dinosaurs were appropriate to their size and standard of life. These huge herbivores had wide feet with a flat base to distribute the great weight of their bodies.

    They were some of the first animals that started walking straightened up. Some of them had claws at the tip of their fingers or feet and used them in different ways. Many primitive dinosaurs had fingers even with varied joints in each of them.
    The bones of their feet were quite resistant and they could open their fingers or toes to balance the weight of their big bodies.
    In the prints of tridactyl bipeds, the ending of the fingers or toes may be either that of ornithopods or sharp-pointed like the prints of theropods claws.
    As we can observe, we can also differenciate carnivores from herbivores when studying prints.
    In the tour, you will visit a rock exposure belonging to the Candlestick Formation which is probably around 90 or 100 million years old.
    In this place, there is an interesting amount of preserved footprints of biped dinosaurs both carnivores and herbivores. The prints are very well appreciated on the redish rock that had once been mud on the verge of a lake existing in those times.
    There are high footbridges similar to brd cages for visitors to walk over the footprints and to preserve them from ravaging

How to get to the Footprints

    To get to the area of footprints, you will have to drive 3 kilometers along Nº 237 National Route departing from the entrance to the dam and going to Piedra del Aguila.
    You will find to your left, next to Llanquén Neighbourhood an entrance that will take you to a road with footbridges that will let you observe quite nearly the trace of past.