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Essay Unit 1 chemsitry and our earth
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natural activity in the world
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The planet is probably about 4.5 billion years old, there are many natural processes/factors whichhave affected the earth’s atmosphere and surface area over millions of years, three natural factors will
be discussed: Tectonic plates, Volcanoes and Continental drift.
Tectonic plates
The first crustal land masses on the surface formed about 4 billion years ago. Some natural processes
that have affected the surface crust include plate tectonics. Plate tectonics are the motion of the
crustal plates in the lithosphere. Where plates meet and subduct (one plate passes under another
plate), mountain ranges form. Where plates diverge, oceanic trenches form.
The plates within our planet move because of the intense heat within the earth’s core, which causes
molten rock in the mantle layer to move. It moves in a convection cell pattern that is formed when
warm materials rise, cool and eventually sink down. New parts of a plate rise because they are warm,
and the plate is thin. Hot magma rises to the surface and forms new crust, the new crust pushes the
rest of a plate out of the way. This is called ridge push. Old parts of a plate are likely to sink down
into the mantle at subduction zones because they are colder and thicker than the warm mantle material
underneath them (WTTU, 2010). This process of the plates meeting causes earthquakes to happen, it
also has contributed to the formation of mountains and volcanoes.
Because of this tectonic plate movement continental drift is happening
Continental drift
Wegner said that continents were once connected (Pagaea) super continent that existed around 250
million years ago and somehow over millions of years moved apart and are where they are today. He
suggested that the continents are constantly moving (Baraniuk, 2016). The continents are apart;
however, they are shaped to fit together. Mesosaurus fossils were examined, there are only two places
these are found; eastern coast of south America and western coast of Africa, distance is too great for
them to swim across and would not be able to survive in salty water. He argued that the two
continents were connected at the time of the species and after their extinction the land masses were
torn apart and separated, hence why fossils are found in both places (Evidence, 2019). Other fossil
distributions found were: lystrosaurus, Glossopteris, Cynognathus. Mountain ranges were also
examined, a pattern was found, north eastern united states mountain ranges and northern Europe
match up perfectly, made up of the same type and same age of rock. Coal forms from tropical plants,
yet it is found in Antarctica, northern Europe, northern Asia, southern tip if Africa and Australia,
these are not tropical climates, however, they have coal which is evidence of past tropical climate
suggesting movement of climates over time (Evidence, 2019).
Volcanic Activity:
The first billion years, the earth was extremely hot, volcanoes just erupted spreading magma, the early
atmosphere consisted of poisonous gases which came from the volcanoes such as; carbon dioxide,
hydrogen and nitrogen (Wei-Haas, 2015). There was no oxygen or methane at this time as these gases
come from living things and there was no human or any sort of life at this point.
Over millions of years comets and asteroids made from ice bombard the earth, when they hit the earth
they melted, this then formed oceans, rivers etc (Greene, 2013). There was now water, were there is
water there is life, photosynthesis started to happen, and plants formed which then released another
gas into the atmosphere which is oxygen. The CO2 that was consuming the earth had decreased as the
plants were now taking it in. However, now the earth is warming up too much again because human
activity is releasing too much CO2 into the atmosphere.
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