By Fabrcio Caxito
The separation of a Pangea formed an ocean. Didn’t there have been others?
The theory of a technique on plates, which gained strength from 2 years ago 50 perform last century, revolutionized the way ze looked at a world map, with its watertight separations over masses over water and electronic land masses. Pioneers such as German meteorologist Alfred Wegener electronic and South African icemaker Alexander du Toit have released evidence as the fit of these coastlines of America performs South electronic of Africa, of the presence of similar fossil electronic rocks in the two continents beyond, electronic raised the It is the hypothesis that, until about 50 millions of years ago, these two masses were united in one continent, Pangea. The discovery of the split of Pangea from the Jurassic period, generating a new ocean, the Atlantic, sowed the idea that, over time, the continental masses sony ericsson shift, in an eternal dance of continents that caused the electronic opening and closing of oceans electronic the creation of new mountain ranges where two continental masses collided one with the other.
If America performs South electronic the Africa learned separated, as suspected by Wegener electronic Du Toit, why zero Could there have been past zero, between operating system continents electronic oceans, configurations that zero are more able to distinguish due to cycles about electronic opening and closing that followed zero geological pace? Today we know that the Earth is about 4.5 billion years old, enough time for several oceans to have opened closed electronic, electronic, and several fragments of continents have collided electronically formed supercontinents in positions very different from the current ones.
A clue to unravel this puzzle to search, in today’s continents, for traces about ancient oceans that sony ericsson squeezed electronic learned closed when like continental masses collided. The difficulty of undertaking this research, however, is due, among other reasons, to the difficulty of finding pieces of ancient oceans within 2 continents.
The bottom 2 oceans consists of very dense rocks, mostly operating system basalts, some dark rock is very rich in minerals on iron and electronic magnesium, quite different from 2 granites that characterize operating system continents, rich in silica electronic aluminum, lighter elements. Thankfully, in some very specific situations, pieces of basalt that were previously part of the ocean floor ended up sony ericsson sticking in half t rocks perform continent, thus being preserved for future investigations.
This happened It is, for example, in the subduct zones, which thus those where some tectonic plate entered beneath another electronic plate sank into an earth’s mantle. In this movement, pieces of basalt perform bottom perform ocean may have learned detached from the submerged plate electronic raised plate where the continent that had been above was. Operating system small pieces of basalt were preserved as chips on operating system electronic granites and continental sedimentary rocks. That is, these neighboring thus rocks are very different from yours. They have some specific dark green coloration 2 basalts electronic other rocks associated with them, electronic hence they were called ophioliths, perform greek ophios (snake) electronic lithos (rock).
Find ophiolites In the field electronics pr the mo na a piece preserved over an ancient ocean some huge joy for operating system scientists. This is what happened in the Monte Orebe region, in the wilderness on the border between Pernambuco electronic Piau, when, in 2014, a group of researchers, performing which I am part, found electronic described a piece on an ocean about about about 820 millions of years ago electronic named it the ophiolite Mount Orebe. The study, published in the journal Geology electronic, helped to unravel the configuration over ancient tectonic plates, electronic continents oceans in the northeast perform Brazil.
Interestingly, the region over Monte Orebe is logo design north of a dam over Sobradinho, Bahia. Electronic was the construction of the dam that inspired the famous song about S electronic Guarabyra (in turn inspired by the prophecies about Antnio Conselheiro): The wilderness will turn scar, heartfelt / fear that one day the scar will also turn into the wilderness.
Fabrcio Caxito teacher on geology electronic student on philosophy at UFMG.
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