It is known that in the Upper Jurassic Asturias had an extremely arid climate, and its coasts were low, with no cliffs initially. A huge marsh in which the minor and major traces of all the organisms that survived in that environment were inscribed. The dinosaurs, specific, found in this mud, seat at the same time of numerous fluvial deltas, an ideal place to satisfy your survival patterns.
Now, many of the finds and numerous replicas of animals from that era can be seen in one of the most visited museums in Asturias: the Jurassic Museum. Its founding collection is made up of more than 8.000 specimens of fossils coming exclusively from the Asturian Jurassic. The investigations are being carried out by a team led by the professor of Geology of the University of Oviedo, José Carlos García Ramos.
Jurassic Museum - MUJA
In a privileged place on the coast of Asturias a few meters above sea level, is located the ... Read more
The dinosaur coast
A dense coastal strip of more than 60 kilometers It serves as study material for researchers. A natural archive that in this area is arranged in a series of gigantic slices that make up what geographers call statigraphic formations. The specific limits of the Jurassic period on the Asturian coast, those that contain these formations, extend from Cape Torres, west of Gijón, to the stone of Arra, two kilometers east of Ribadesella (two important faults serve as an exact border with the oldest rocks of another type of coast that goes back further, to the Paleozoic).
The Mesozoic era occupies a substantial part in the materials of these layers. Traces of gilliopods, saudopods, theropods and others, both bipedal and quadruped, carnivores or vegetarians, are the most abundant data, with measurements ranging from the foot of a pigeon to that of an elephant multiplied by ten. But in this privileged plot of the peninsular coast there are also remains of turtles, crocodiles and marine reptiles, fish, vegetables, trunks, small organisms, traces of jurassic waves, stream marks of that time, and countless other traces.
They have been cataloged 5 different types of geological formationsNone of them are mutually exclusive, as they are theoretical models.
La Gijón Formation It is the oldest (between 206 and 199 million years old), is located at a height of over 100 meters and is abundant in limestone and fossils of bivalves and gastropods.
La Rodiles Training It is 25 million years younger; here, reptile and fish bones already appear, in addition to invertebrate fossils.
La Vega Formation It has a height exceeding 150 meters, transitioning from limestone to gray sandstone and red shale. It dates back to a time before 154 million years ago. Here we already find small crustaceans, plant remains, footprints, and dinosaur bones.
La Tereñes Training It is even younger and dates from the time when Asturias was a kind of muddy inland sea.
Por último, la Ballast Formation, The youngest of the five, 151 million years old, is also very abundant in fauna and flora finds. In this period Asturias presented a more advanced landscape, populated by small river deltas, marshes and swamps.
What dinosaur footprints will we find?
Although there are many tastings and discoveries, the main attraction of the Asturian Jurassic coast lies in the extraordinary amount of ichnites found. A density and variety of footprints very rare elsewhere. In addition to the classic depressions in the rocks, there are also the "countermolds", very abundant. These are obvious traces that appear upward, due to the effect of sedimentation later in time that covered them.
The walking routes that we propose below could be frustrating if you do not have a guide, hence some minimal descriptive notes are necessary to avoid overlooking the trails:
1/ The shape of the ichnites Whether we find it depends on 4 main factors: anatomy (foot shape), substrate (sediment conditions), behavior (speed, balance of the animal...) and preservation. Therefore, it is not advisable to look for the typical tridactyl footprint that is perfectly defined and marked.
2/ Type of dinosaurs. Based on their mode of locomotion, they can be classified into bipeds and quadrupeds.
The earliest dinosaurs, such as theropods and most ornithopods, walked upright. Quadrupeds, like sauropods and those with horns, plates, and armor, used both their forelimbs and hindlimbs. Generally, the tracks of quadrupedal dinosaurs are wider than those of bipeds due to their different body structure. Among quadrupedal dinosaurs, sauropods are the most common; their footprints are circular or rectangular, while their handprints tend to be crescent-shaped. Both theropods and ornithopods generally produce bipedal tracks, consisting of tridactyl footprints. Distinguishing between the two types of footprints is not always straightforward, but theropod footprints tend to be more slender, with longer, narrower toes.
Walking routes along the Jurassic coastline
The road access that brings us closer to the Asturian Jurassic sites has as its main routes the Cantabrian Highwayor on the eastern slope of the Principality, as it passes through Ribadesella, Caravia, Colunga and Villaviciosa, as well as regional highway 256 and national highway 632These are the ones we will necessarily have to detour to at some point to get closer to the coast. main deposits found to date:
Merón Beach Villaviciosa
There are two alternatives, one is taking the detour from the As-256 regional road to Careñes, where you have to leave the car and take a descending path that starts from the town church in the direction of the beach [900 meters]. The other part of the Argüero deviation, following the signs indicating the beach.
Once there, the route begins westward along the base of the cliff for about 600 meters until reaching a sandstone stratum of the Lastres Formation. On its surface, the following is preserved: The trail of a sauropod [quadruped], formed by 12 consecutive hand and foot printsThere are also scattered tridactyl footprints of bipeds.
Cliffs of Oles Villaviciosa
Starting from the regional As-256, at the height of El Gobernador, take the deviation that leads to Oles and Tazones. Upon reaching the first of these two towns, a very narrow paved road starts on the left and heads north, passing in front of the parish church of Oles, where there is a small parking lot to leave the vehicle. From there, a path begins that must be followed for 900 meters until it joins a path after a 90-degree turn to the west, which ends just above a broad stratum of sandstone slightly inclined towards the sea.
There are 12 tracks of bipedal dinosaurs oriented in various directionsThe rocks belong to the Lastres formation and among them stand out several sandstone strata with undulating surfaces due to Jurassic water currents and waves.
Tazones Villaviciosa Lighthouse
The explanatory panel is located at the beginning of a path that starts on the left side of the road that leads to the lighthouse. Following the signs you access the cliff after a journey of 1.300 meters.
Right there, on a slab of rock slightly inclined towards the sea The first three-toed dinosaur footprint is foundFrom here, continuing to the right (east), you reach the surface of a sandstone stratum, inclined about 25 degrees towards the sea, which displays numerous tridactyl footprints that intersect in various directions and form several tracks, as well as a tail drag mark. This is a rare example in the fossil record, since, contrary to what was thought until recently, dinosaurs walked with their tails held upright to maintain balance.
In adjacent strata with the same orientation, various ichnites of hands and feet of quadruped dinosaurs, seen in plan view, as well as the vertical section of one of them of large dimensions, probably from a sauropod.
Another 60 meters further in the same direction, on the vertical wall of the cliff, you can see ichnites of quadrupeds with sandstone filling as bulges at the base of the subhorizontal strata of the same composition or isolated inside gray marl.
Tazones Beach Villaviciosa
There is an information panel on Tazones beach. Starting from the panel itself, you continue along the beach and the cliff; about 120 meters from the panel, on the surface of a gray stratum, inclined at about 45 degrees, several formations can be observed. tridactyl footprints belonging to bipedal dinosaursoriented in various directions. Some of them form a trail.
If we continue for about 480 meters in the same direction, and already within the Vega Formation, of fluvial origin, another tridactyl dinosaur footprint can be seen forming a countermold at the base of a sandstone projection as an eave located several meters high. .
Puerto de Tazones Villaviciosa
On the cliff at the western end of Tazones, a few meters past the port's breakwater, a magnificent example of a vertical fault can be observed within an alternating succession of sandstones, shales, and marls. A few meters further on, several examples of vertical root traces surrounded by a pale green halo against a reddish rock background can be seen. Jurassic paleosols.
Lastres Colunga Cliffs
From the coastal road N-632 at Colunga, take the regional road As-257 that leads to Lastres. After passing this town and after traveling 1,5 kilometers you reach Luces, where you take a detour to the right along a narrow paved road that leads to the Lastres lighthouse. About 650 meters before reaching the lighthouse, a path starts straight ahead along which we must travel about 850 meters to the foot of the cliff.
Nearby, and slightly to the east, lies a loose block of sandstone with two counter-molds of dinosaur footprints, one tridactyl from a biped and another crescent-shaped [sauropod]Continuing along the base of the cliff to the west for about 300 meters, you reach some inclined sandstone strata on which there are several tridactyl footprints and a sauropod track, the latter quite worn down by the action of the sea.
Numerous fragments can also be observed fossilized trunks of Jurassic trees up to 50 cm in diameter.
Greek Colunga Beach
Playa de la Griega can be reached from the N-632, turning off towards Colunga and then taking the road that leads to both Lastres and La Griega beaches. To reach La Griega, however, you need to take a road to the right. There is an information panel on the right bank of the estuary, immediately after crossing the bridge, very close to the campsite. From there, continue towards the cliff on the eastern side of the beach.
About 500 meters from the explanatory panel, two decimeter-scale protuberances appear on the surface of a loose block of red sandstone, corresponding to counter-molds of a handprint and a footprint of quadruped dinosaurs, oriented in opposite directions.
Continuing along the same cliff edge for another 150 meters, you reach a stratum of sandstone gently sloping towards the sea, its surface crisscrossed by joints (tectonic cracks) in various directions. Less than a meter above this lies a gray limestone containing tiny gastropod fossils y several large depressions [up to 1,3 meters in diameter] rounded.
They are footprints of large quadruped dinosaurs that show a bulging peripheral rim. These are the largest ichnites in Spain, and due to their size they can be considered among the largest in the world.The dinosaur that made them must have been a colossal specimen, a gigantic quadrupedal sauropod whose weight could have been around 100 tons. Besides these, a trail formed by six footprints can be observed, also corresponding to a smaller sauropod.
Laterally and on the same surface, other tridactyl ichnites appear that form a trail that is somewhat more difficult to identify. About 30 meters further on, some red sandstones from the Vega formation can be seen, which contain traces of pale green verticalized roots, corresponding to ancient paleosols located in areas lateral to the bed of a Jurassic river. The distance between the explanatory panel and the end of the itinerary is about 600 meters.
Vega Ribadesella beach
Access from the N-632 coastal road is located around the town of Torre, about 6 kilometers east of Ribadesella. From there starts a 1,8 kilometer paved road that leads to Vega beach.
A few meters from the eastern end of the parking lot, formations containing abundant marine fossils can be seen. Above them lies a one-meter-thick layer of conglomerate made of siliceous pebbles; eight meters above this, a sandstone stratum is visible, at the base of which there are several tridactyl footprints of bipedal dinosaursThe geological composition is typical of this Vega formation, which is predominantly of fluvial origin. It is not easily accessible.
Cliffs of Tereñes Ribadesella
Take the road up to Tereñes until you reach a high point where it makes a sharp left turn at a crossroads. From here, where the information panel is located, take a narrow road that descends gently for 200 meters. A path to the right leads to the cliff. Along this particular stretch of coastline, an inland sea once gently lapped, protected from the rougher waters by a geological formation acting as a dike.
Once there, the tour begins from right to left [westward]. Various dinosaur footprints can be observed, among which the following stand out: three tracks, two of bipedal and tridactyl dinosaurs and another very spectacular one of quadrupeds, in which hand and foot prints can be seen. They are located on a flat, sloping rock, as is typical in these cases. The first scientific study of these footprints concluded with "dinoturbation," that is, a mass of randomly distributed footprints resulting from a massive influx of dinosaurs of all kinds at the same site.
However, the theory has recently changed. If we analyze the stride length, the size of the tracks, and their orientation with respect to an axis, we discover—surprisingly, and this is a finding of great importance in the continental Europe of the dinosaurs—that the tracks are parallel to each other, with an astonishing symmetry that tells us that Those "monsters" walked in a pack through that place, taking a leisurely stroll and displaying their gregarious behavior..
Most of the footprints belong to herbivorous bipeds, although it's striking to see another, different trackway extending perpendicularly towards the first set of tracks at the very top of the rock. These tracks have sharper toes and belong to carnivorous bipeds, the kind that commonly preyed on the herd. Thousands of years may have passed between the footprints of the herd and those of the carnivore.
In a small cove about 90 meters southwest of the Forno rock there is a block of reddish sandstone fallen at the foot of the cliff in which there are small tridactyl footprints created by bipedal dinosaurs.
The total route along the base of the cliff that contains the main ichnites as well as very striking examples of Jurassic desiccation cracks is about 400 meters.
Ribadesella beach
At the western end of Santa Marina beach, At the end of the so-called Mirador del Pozu, there is an explanatory panelLooking south, you can see gray Carboniferous limestones that stand out in the relief of the vertical wall.
Near the end of the walk, we find an alternation of marls and limestones with interbedded sandstones, which extends along the cliff to the west. It displays several layers rich in very small bivalves, as well as desiccation cracks and frequent dinosaur footprintsThese appear on the surface of the strata as depressions with an oval or tridactyl outline.
On the same descent to the cliff from the viewpoint at the end of the walk you can see some of these footprints. From here and continuing about 150 meters to the west along the base of it, there is a large slab of sandy limestone inclined to the sea at about 80 degrees. On it there are several traces of sauropod [quadruped] footprints.
Text: © Ramón Molleda for asturias.com
