Continental drift defines one that the earliest methods geologists believed continents relocated over time. Today, the concept of continental drift has actually been changed by the scientific research of key tectonics.
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Continental drift explains one that the earliest methods geologists assumed continents relocated over time. Today, the concept of continent drift has actually been changed by the science of plate tectonics.
The theory of continental drift is most linked with the scientist Alfred Wegener. In the early on 20th century, Wegener published a document explaining his concept that the continental landmasses to be “drifting” throughout the Earth, sometimes plowing v oceans and also into each other. He referred to as this motion continental drift.
Wegener was persuaded that all of Earth’s continents were once component of an enormous, solitary landmass dubbed Pangaea.
Wegener, trained together an astronomer, used biology, botany, and also geology describe Pangaea and also continental drift. Because that example, fossils that the ancient reptile mesosaurus room only discovered in southern Africa and also South America. Mesosaurus, a freshwater reptile just one meter (3.3 feet) long, can not have actually swum the Atlantic Ocean. The existence of mesosaurus suggests a single habitat with countless lakes and also rivers.
Wegener additionally studied plant fossils native the frigid Arctic archipelago that Svalbard, Norway. This plants were not the durable specimens adjusted to survive in the Arctic climate. These fossils were of tropic plants, i beg your pardon are adjusted to a lot warmer, an ext humid environment. The presence of this fossils says Svalbard once had actually a dry climate.
Finally, Wegener studied the stratigraphy of different rocks and mountain ranges. The east coastline of south America and the west coastline of Africa seem come fit together prefer pieces the a jigsaw puzzle, and also Wegener uncovered their rock layers “fit” simply as clearly. Southern America and also Africa were not the just continents with similar geology. Wegener discovered that the Appalachian mountains of the eastern united States, for instance, to be geologically related to the Caledonian mountains of Scotland.
Pangaea existed around 240 million year ago. By around 200 million year ago, this supercontinent began breaking up. Over millions of years, Pangaea separated into pieces that moved away from one another. This pieces progressively assumed your positions together the continent we recognize today.
Today, researchers think that number of supercontinents choose Pangaea have actually formed and also broken up over the food of the Earth’s lifespan. These include Pannotia, which formed around 600 million year ago, and Rodinia, i beg your pardon existed more than a billion year ago.
Scientists did not accept Wegener’s concept of continental drift. Among the facets lacking in the concept was the system for exactly how it works—why go the continent drift and what fads did castle follow? Wegener argued that probably the rotation that the planet caused the continent to change towards and apart from each other. (It doesn"t.)
Today, we recognize that the continents rest on huge slabs the rock called tectonic plates. The bowl are always moving and interacting in a process called bowl tectonics.
The continents are still moving today. Several of the many dynamic website of tectonic activity are seafloor dispersing zones and giant rift valleys.
In the procedure of seafloor spreading, molten rock rises from in ~ the Earth and adds brand-new seafloor (oceanic crust) to the edge of the old. Seafloor spreading is most dynamic along large underwater mountain ranges well-known as mid-ocean ridges. As the seafloor grow wider, the continents on opposite political parties of the ridge move away from every other. The phibìc American and also Eurasian tectonic plates, for example, space separated through the Mid-Atlantic Ridge. The two continents are relocating away native each various other at the price of about 2.5 centimeters (1 inch) per year.
Rift valleys room sites wherein a continent landmass is ripping chin apart. Africa, for example, will certainly eventually break-up along the an excellent Rift sink system. What is now a single continent will arise as two—one ~ above the afri plate and also the various other on the smaller sized Somali plate. The brand-new Somali continent will certainly be mainly oceanic, with the Horn the Africa and also Madagascar its largest landmasses.
The procedures of seafloor spreading, rift valley formation, and also subduction (where more heavier tectonic bowl sink beneath lighter ones) were not well-established till the 1960s. These procedures were the main geologic forces behind what Wegener well-known as continent drift.
The method some continents fit together favor puzzle pieces motivated the theory of continental drift.
Map through USGS
Colliding SkywardThe collision the the Indian subcontinent and Asian continent created the Himalayan hill range, residence to the world"s greatest mountain peaks, consisting of 30 the exceed 7300 meter (24,000 feet). Since continental drift is still pushing India right into Asia, the Himalayas room still growing.
Alfred Wegener’s original name for his proposed, ancient continent to be “Urkontinent”—ur an interpretation “first or original,” and kontinent meaning “continent” in Wegener’s native language, German. A much more popular surname for this large ancient landmass is Pangaea, which way “all lands” in Greek.
study of the physical background of the Earth, that is composition, its structure, and the processes that kind and readjust it.
series that faults and also other website of tectonic activity stretching from southwestern Asia to the Horn of Africa.
massive slab of heavy rock made up of Earth"s lithosphere (crust and also upper mantle). Likewise called lithospheric plate.
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existing in the tropics, the latitudes between the Tropic the Cancer in the north and also the Tropic of Capricorn in the south.
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