Origin And Structure Of The Earth
Earth
-The only planet in the solar system to support life. Our planet has an atmosphere (ozone layer)
that shields us from the harmful rays that are coming from the sun.
-The only place in the known universe confirmed to host life and the only one with accessible
water on the surface for the inhabitants to use.
-It is made up of 70% water
-It is sometimes called the "Blue Planet" Ao Sekai lol
-The main reason this planet is habitable is because it has the right amount of distance from the
sun. Not too cold and not too hot, just right.
-It has elements that are important for supporting life like carbon and oxygen.
-It provides water, oxygen, biological products, suitable weather that are important in
supporting life in that world.
Earth has:
! Water
! Plate tectonics
! Several layers of Atmosphere
Differences or Earth from Venus and Mars:
[Similarities]
# They all have terrestial characteristics made from solid rocks and silicates.
# They all have an atmosphere
# They almost have the same time to rotate on their axis
# Earth and Mars both have water
# They all have carbon dioxide
# All have landforms
[Differences] <obvious already, no?
# Venus has not water
# Earth is only habitable (for now, who knows maybe elon knows?)
# Venus and Mars have no oxygen
# Earth is in the habitable zone of the solar system
Rocks
-Earth is a solid rock to a depth of 2,900km, where the mantle meets the liquid outer core. A
rock is a naturally occurring solid aggregate of one or more minerals. The aggregate minerals forming
the rocks are held together by chemical bonds. Grains can be different in color, texture, and sizes.
# Geologists groups rocks into 3 categories:
! Igneous
! Sedimentary
! Metamorphic
# Petrology
! Scientific study of rocks
! Classify rocks based on how they were formed
Three types of rocks:
! Igneous
-Formed from hardening and crystallization of magma or molten materials that
originates deep within the earth.
# Two types of Igneous Rocks
-Extrusive/Volcanic Rock
~Forms when magma makes its way to the
earths surface as lava and cools. The
crystals are very small or fine grained
since the cooling process is so fast.
-Intrusive/Plutonic
~It cools slowly beneath the earth's
surface and are created by magma, unlike
the extrusive ones, this type have very
large crystals or coarse grained.
# Igneous rocks are classified based on:
[Composition]
! Felsic > Light in color; feldspar and silicates
! Mafic > Dark in color; magnesium and iron
! Intermediate > Between Felsic and Mafic
! Ultramafic > Very dark in Color
[Texture and Appearance]
! Aphanistic > Fine grained
! Phaneric > Coarse grained
! Porphyritic > Large crystals with small crystals
! Glassy > Non-ordered soid from rapid quenching
! Pyroclastic > Composite of ejected fragments
! Sedimentary
-They provide information about the surface conditions that existed in the earth's past.
-Particles of sand, shells, pebbles, and other fragments of materials called sediments,
accumulate in layers and over long period of time harden into rocks.
-Compaction due to increase of pressure of layered sediments, it binds together to form
the sedimentary rock.
# Three types of Sedimentary rocks
[Clastic]
~Formed from accumulation of clasts; little
pieces of broken rocks and shells.
~Breccia, Sandstone, and Shale
[Chemical]
~Formed when dissolved minerals precipitate
from a solution.
~Halite; formed when seawater body becomes
enclosed and evaporates
[Organic]
~Rocks formed from the accumulation of
animal debris.
~Coal; formed from plant fragments
! Metamorphic
-Forms pre-exisiting rocks either metamorphic, igneous, or sedimentary like quartzite,
marble, slate, and phyllite.
! Metamorphism
-Transformation of one rock into another
# Two types of Metamorphism
[Regional]
~Due to changes in pressure and temperature
over large region of the crust
[Contact]
~Mainly by heat due to contact with magma
# Classification
[Texture]
~Referes to the size arrangements and grains
within the rock.
[Foliation]
~Any planar arrangement of mineral grains or
Structural features within the rock
**Foliated > Appeared banded or
layered, contains crystals.
**Non-Foliated > Made up of only
few minerals.