Internal Structure of Earth, Minerals, and Rock Types

A complete vocabulary set detailing Earth's interior layers, direct/indirect study sources, elemental composition of the crust, major mineral categories, and the three main rock types.

Minerals

Naturally occurring inorganic substances with a specific structure and a definite chemical composition.

Radius of the Globe

The estimated radius of the Earth, recorded as $6500\,km$.

Mining (South Africa)

The process of extracting useful materials; in the Republic of South Africa, gold has been extracted from $3\text{-}4\,km$ deep.

Kola Peninsula Project

A Russian deep ocean drilling project that reached the deepest point into the Earth at $12\,km$.

Direct Sources

Methods used to study Earth's interior, including mining, volcanic eruptions, and deep ocean drilling projects.

Indirect Sources

Methods used to study Earth's interior through phenomena such as earthquakes and meteorites that fall to Earth.

Oxygen (Crust Composition)

The most abundant element in the Earth's crust, making up $46.6\%$.

Silicon (Crust Composition)

The second most abundant element in the Earth's crust, making up $27.72\%$.

Aluminium (Crust Composition)

An element making up $8.13\%$ of the Earth's crust.

Carbonate Minerals

A group of major rock-forming minerals that includes calcite and dolomite.

Chloride Minerals

A group of rock-forming minerals that includes rock salt.

Sulfate Minerals

A group of rock-forming minerals that includes gypsum.

Sulfite Minerals

A group of rock-forming minerals listed to include pyrite and galena.

Oxide Minerals

A group of rock-forming minerals that includes quartz and magnetite.

Crust

The outermost and thinnest layer of Earth, divided into Continental (SIAL, $30\text{-}40\,km$ thick) and Oceanic (SIMA, $5\text{-}10\,km$ thick).

Mantle

The layer of Earth that is $2900\,km$ thick, comprising $84\%$ of Earth's volume, associated with SIMA.

Core

The innermost layer composed of NIFE at $6000^\circ C$, comprising $15\%$ of Earth's volume, divided into a solid inner core and semi-fluid outer core.

SIAL

Composition abbreviation for Silicon and Aluminium, which makes up the continental crust.

SIMA

Composition abbreviation for Silicon and Magnesium, which makes up the oceanic crust and mantle.

NIFE

Composition abbreviation for Nickel and Iron, which makes up the Earth's core.

Igneous Rock

Rocks formed when magma reaches the surface or solidifies, derived from the Latin word 'ignes' meaning 'fire'.

Lava

Magma that reaches the surface of the Earth.

Extrusive Igneous Rock

Also called volcanic rocks; formed when magma solidifies at the surface, such as basalt or obsidian.

Intrusive Igneous Rock

Also called plutonic rocks; formed when magma cools inside the Earth, such as granite.

Magma Formation Depth and Temperature

Magma is produced $60\text{-}200\,km$ deep where Earth's temperature ranges from $900^\circ C$ to $1600^\circ C$.

Sedimentary Rock

Rocks derived from the Latin word 'sedimentum' meaning 'settling', mostly found in rivers due to erosion, containing layers and fossils.

Metamorphic Rock

Rocks formed by heat and pressure altering existing rocks, derived from Greek 'meta' (change) and 'morpho' (form).

Metamorphism

The geological process of changing a rock's form through heat and pressure.

Marble

A metamorphic rock that is formed from limestone, a sedimentary rock.