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04-09-2022, 08:53 PM
Noticias:
Ajuy Basal Complex, from when dinosaurs dominated the earth.
On the northern cliff of the Barranco de Ajuy emerges a basaltic area dating between 100 and 150 million years ago.
Although the basal complex of the area was formed in the Cretaceous, when tyrannosaurs roamed freely as the predator at the top of the food pyramid, if it is true that this complex would see the light as part of an island millions of years later, already in the Cenozoic era, according to the latest studies between 25 and 30 million years ago, being by far the oldest area of the Canary Islands.
Geologically this space has, in this sense, a special relevance, since in it are located the oldest materials of the entire Archipelago. On the cliff located on the northern margin of the Barranco de Ajuy, north of the town, you can see the outcrop of the Basal Complex, whose age, as we say, ranges between 100 and 150 million years, having formed, therefore, at the time that dinosaurs ruled the planet.
The oldest rocks, therefore, are sediments typical of the great marine depths that rose, visible in few places on the planet, which are called phthanites. These are quartz sands with rhythmic and dark bands, belonging, as we say, to the Jurassic-Cretaceous period.
If we compare this antiquity with the one estimated to have the surface outcrop of this area of the island, between 25 and 30 million years, it is still one more reason for its great scientific interest. These materials were generated during the separation of the African and American continents, coinciding with the formation of the Atlantic Ocean, also showing numerous more recent magmatic intrusions in the form of dikes.
In this sense, a visit to this northern cliff takes us on a leap in geological time of more than 100 million years, a trip to the past that surpasses even the formation of Fuerteventura itself, whose geological age, as we say, is much later.
Pliocene, fossilized beaches
Subsequently, variations in sea level gave rise to the formation of a marine sedimentary deposit on which we can observe the presence of paleodunes from the Pliocene period that are located more than 14 meters above current sea level. Thus we find a fossilized beach of four million years that presents sediments from the ocean floor.
In addition, the ftanites of the basal complex are crossed by a multitude of dikes and on them is located a marine deposit of conglomerates and sandstones that house abundant fossil fauna (shells and shells) from five million years ago, which indicates the existence of a very warm climate, located at a height that varies between 10 and 60 meters.
These facts indicate that modern climatic oscillations began as early as the Pliocene epoch. Contemporaneously with the formation of these deposits, a basaltic stream reached the sea, being later eroded by the waves, fragmenting it and generating pebbles that are observed interspersed in the marine deposit.
It should be remembered that in the Pliocene, "only" about 4 million years ago, the continents were still adrift and formed, for example the Meditaráneo in a clash between Africa and Europe, or joined South America with North America.
In this way, the existence of fossils in marine and wind deposits constitutes a record of great importance in order to interpret and know in greater detail the global climate changes that have occurred on the planet over the last millions of years.
Some of the most notable testimonies derived from these changes can be observed thanks to the drop in sea level after the last regression. In addition, the fossils found mark the evolution of some of the marine organisms that were present in other times.
link to article for pics and diagrams
Ajuy Basal Complex, from when dinosaurs dominated the earth.
On the northern cliff of the Barranco de Ajuy emerges a basaltic area dating between 100 and 150 million years ago.
Although the basal complex of the area was formed in the Cretaceous, when tyrannosaurs roamed freely as the predator at the top of the food pyramid, if it is true that this complex would see the light as part of an island millions of years later, already in the Cenozoic era, according to the latest studies between 25 and 30 million years ago, being by far the oldest area of the Canary Islands.
Geologically this space has, in this sense, a special relevance, since in it are located the oldest materials of the entire Archipelago. On the cliff located on the northern margin of the Barranco de Ajuy, north of the town, you can see the outcrop of the Basal Complex, whose age, as we say, ranges between 100 and 150 million years, having formed, therefore, at the time that dinosaurs ruled the planet.
The oldest rocks, therefore, are sediments typical of the great marine depths that rose, visible in few places on the planet, which are called phthanites. These are quartz sands with rhythmic and dark bands, belonging, as we say, to the Jurassic-Cretaceous period.
If we compare this antiquity with the one estimated to have the surface outcrop of this area of the island, between 25 and 30 million years, it is still one more reason for its great scientific interest. These materials were generated during the separation of the African and American continents, coinciding with the formation of the Atlantic Ocean, also showing numerous more recent magmatic intrusions in the form of dikes.
In this sense, a visit to this northern cliff takes us on a leap in geological time of more than 100 million years, a trip to the past that surpasses even the formation of Fuerteventura itself, whose geological age, as we say, is much later.
Pliocene, fossilized beaches
Subsequently, variations in sea level gave rise to the formation of a marine sedimentary deposit on which we can observe the presence of paleodunes from the Pliocene period that are located more than 14 meters above current sea level. Thus we find a fossilized beach of four million years that presents sediments from the ocean floor.
In addition, the ftanites of the basal complex are crossed by a multitude of dikes and on them is located a marine deposit of conglomerates and sandstones that house abundant fossil fauna (shells and shells) from five million years ago, which indicates the existence of a very warm climate, located at a height that varies between 10 and 60 meters.
These facts indicate that modern climatic oscillations began as early as the Pliocene epoch. Contemporaneously with the formation of these deposits, a basaltic stream reached the sea, being later eroded by the waves, fragmenting it and generating pebbles that are observed interspersed in the marine deposit.
It should be remembered that in the Pliocene, "only" about 4 million years ago, the continents were still adrift and formed, for example the Meditaráneo in a clash between Africa and Europe, or joined South America with North America.
In this way, the existence of fossils in marine and wind deposits constitutes a record of great importance in order to interpret and know in greater detail the global climate changes that have occurred on the planet over the last millions of years.
Some of the most notable testimonies derived from these changes can be observed thanks to the drop in sea level after the last regression. In addition, the fossils found mark the evolution of some of the marine organisms that were present in other times.
link to article for pics and diagrams
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