Instead of one of Africa will have two?

Australian researchers found that after a while Africa may split in two. They explored the rift (the boundary between two lithospheric plates) Rukwa in Tanzania and found that tectonic activity of the place is still very high. Curiously, all the processes occurring there, very similar to the beginning of the fault of the continent.

As we remember, 180 million years ago there was no Africa — the continent with South America, Australia, Antarctica, and the Indian subcontinent, Arabia, Madagascar and New Zealand was part of the supercontinent Gondwana. However, after 30 million years, the continent suddenly cracked, split the two parts. One of them included the Africa and South America, the other — all the rest. And after a while parts of Gondwana finally fled in different directions.

Since continents calmed down — it seems no one else is going to split up. Except perhaps that of Africa — for her "bad" example of Gondwana was contagious. Scientists have long known that today the East African Rift Valley is an area of potential faults. This place has increased tectonic activity and, in addition, is the boundary where different lithospheric plates converge.

A team of scientists from James Cook University (Australia), led by Eric Roberts decided to study the processes occurring in these places. Rift attracted the attention of researchers (the boundary between lithospheric plates) Rukwa located in Tanzania — the western branch of the East African rift system. Currently there are no active volcanoes, and this facilitates the work, as the observed effects can not be attributed to the activities of the fire-breathing mountains.

According to researchers, good data on tectonic processes from a study of some river channel changes. After all, the river is very sensitive to such things as mountain building, uplift of the crust and dips. It was decided to do research floodplain Congo. First, the researchers analyzed the traces of geomagnetic reversals (that is, changes in the magnetic field of the Earth) in river sediments. Next, determine the age of volcanic ash deposited on the ancient shores of the Congo.

Then analyzed the sediments of ancient river valley. Since it is known that rivers erode rocks formed in different geological epochs, it is reasonable to assume the following: if the channel shift (for example, the rise of the surface), then the structure and composition of the rocks that were in the way of water. And this is already possible to judge where the proper course of the river in ancient times and how it changes over time.

The results showed that in the Cretaceous Congo River flowed mainly in the north-west, as sediment carried out geological provinces of the south-east. But in the Oligocene (34-23 million years ago), she rezkosmenila course, choosing the south-east. Such common when climbing or mountain building — for example, if in the vicinity of Astrakhan crust would rise, Volga flowed to the north. Therefore, something similar happened in the Oligocene and Rukwa Rift.

But now Congo again flowing to the north-west. Moreover, according to the data obtained in the study, the top layer of sediment, changing its "course" happened some 25 million years ago. That is on the rift crust rose again, but with the other hand.

What can all talk about? We know that before the fault is always raising the crust. Actually, the fault is caused by the fact that the Earth's mantle pushes outward substance, and they escape, where the crust is thinner. At first, the upper, less dense parts of the cortex is folded — this is the mountains.

However, the newly formed folds hamper output material from the mantle to the surface: they seem to act as corks in bottles of champagne. Below them is increasing pressure, at some point the crust does not hold and the substance of the mantle, pushing the plate, still breaks out. Rift with breaks and, if it happens on the ground, from one continent to get two.

Actually, now in Africa is just the initial stage of the process. SKOPJE the continental mantle material from actively looking for a place to leave, creating more and more lift. So far, the rift broke open only because Africa, which once was the center of an ancient Gondwana, consists of extremely thick plates. But nothing lasts forever — the time will come when they will not stand.

The situation is aggravated by the fact that at present the Eurasia in the Mediterranean area begins to "creep" under the African plate. "Bad" behavior of the neighbor can enhance the already great tension cortex. When the latter reaches a critical point, the Dark Continent gets going just through the Rukwa Rift. In the crack will flood waters of the Indian Ocean, and as a result of one of Africa get two — North West (large) and Southeast (small).

The fate of both parts of the once united continent, too, is likely to be different. Northwestern piece will drift toward South America, so it's possible that after a 30-millionths of separation, the two "sisters" will meet again. And at the south-western part has a choice — it can either move to Australia or to Antarctica. Not even excepting that the two "cruise" to combine in one — then the former half of the Black continent forms a bridge between the two southern continents. In the end, no one will be hurt.

Source: pravda.ru.

Like this post? Please share to your friends: