Dinosaur Footprints in the West Algarve
On the 8th, 9th, 10th August and 5th, 6th, 7th September, 2001, led by geologists from the University of Lisbon.
|Some of the group at the meeting place in Salema, on the 7th September||The rest had already gathered at the first location.|
Fossils are the vestiges of ancient creatures preserved in sedimentary rocks. The vestiges can be bones, footprints, shells and other similar features. Sedimentary means laid down - by the sea, fresh water or wind.
The footprints were preserved when the creature walked through a muddy zone, and these were later filled by a further sediment, without being disturbed.
|The cliffs on the west side of Salema Beach||At the Herbivore prints|
The yellow rocks are limestones of the
Lower Cretaceous lain down around 150 million years ago. (The Lower Cretaceous
rocks of the U.K. are found in the Weald, the Isle of Purbeck (Dorset) and the
Isle of Wight. The main outcrop of Upper Cretaceous rocks in the U.K. is the
Chalk of the North and South Downs.) These are visible in the coast from Porto
do Mós to Sagres and again at Aljezur.
Rocks from the Jurassic period, below these, outcrop at Carrapateira.
The red rocks on top of the cliffs are more recent Quaternary strata.
The prints on the shelf of Lower Cretaceous rock are those of a herbivorous biped also known as an Ornithopod. This was a three-toed (tridactyl) creature, and it is the rounded shape of these toes, with no claw marks, that implies it only ate vegetation.
|Four of the eight footprints exposed|
From studies of the footprints more information can be gathered as to how the dinosaur moved. As they are more or less in line, the hips must have been swivelled at each stride. From the length of each, it can be estimated that the animal stood at around 2.20m - at the hips. The upper body would have been inclined forward. From the distance between each step it has been estimated that the dinosaur was moving at around 2km per hour - a gentle saunter!
The beach was then crossed to the eastern side.
|An anticline in the eastern cliffs means that further on||the rocks start to dip almost vertically down|
Here, on the large slab in the photo, are seven footprints - belonging to at least three individual animals. Again tridactyl (three-toed) and bipedal, however these are smaller, with fine toes ending in sharp claws, the footprints of Carnivorous dinosaurs.
The very clear toe-print on the right is the length of a biro.
These prints indicate that
these stood between 70cms and 1m at the hip. There is only one individual that
has left a certain track and from this it was going at 3.5 km per hour.
The presence of small lamellibranch (shellfish, like mussels) fossils - the little white nodules in the photo - give us the sense that these dinosaurs were in an islet and lagoon scenario. The rocks here are slightly younger than those at the base of the western cliffs.
Other footprints are found in the Salema area, but are not as easily accessible.
Three Dinosaur vertebrae (backbone bones) have been found nearer Lagos, but were very eroded.
Geology in the Summer Geologia no Verão
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Last modified: March 02, 2005