Geology: Earth's Layers and Rock Cycle

Mantle

Layer beneath the Earth's crust

Asthenosphere

Upper portion of the mantle behaving plastically

Core

Very dense center of the Earth

Metamorphic Rocks

Changed by heat and pressure within Earth

Geology

Study of rocks and Earth's structure

Geologist

Scientist who studies rocks

Crust

Outermost solid layer of Earth

Rock Cycle

Model explaining rock formation processes

Igneous Rocks

Formed from red hot melted rock

Sedimentary Rocks

Formed from sediments or minerals solidifying

Weathering

Processes breaking rocks into smaller pieces

Erosion

Transport of broken rock material

Deposition

Settling of broken rock material

Biological Weathering

Living organisms breaking down rock

Chemical Weathering

Chemical reactions breaking down rock

Physical Weathering

Mechanical forces breaking down rock

Wind

Carries fine rock particles, causing erosion

Temperature Change

Causes rock to expand and contract, leading to cracks

Glaciers

Frozen rivers slowly carving rocks

Agents of Erosion

Water, wind, gravity, or ice moving rock particles

Prospectors

Search for precious minerals

Delta

Landform at a river's mouth from sediment deposition

Igneous Rock Formation

Complete melting and recrystallization

Metamorphic Rock Formation

Partial melting and recrystallization

Compaction and Cementation

Process forming sedimentary rock from compacted sediment

Melting and Crystallization

Solid rock melting and forming new crystals

Igneous rock

Formed from magma or lava crystallization

Extrusive igneous rocks

Formed at or near the Earth's surface

Intrusive igneous rocks

Formed from magma cooling below the surface

Crystals

Interlocking mineral structures in igneous rocks

Magma

Molten rock beneath the Earth's surface

Lava

Magma that reaches the Earth's surface

Rapid cooling

Leads to small or no crystals in igneous rocks

Slow cooling

Allows crystals to grow larger in igneous rocks

Texture

Smoothness or roughness of a rock's surface

Colour

Linked to minerals present in the rock

Basalt

Dark-coloured extrusive igneous rock

Dolerite

Intrusive igneous rock with larger crystals

Granite

Intrusive igneous rock composed of quartz, feldspar, and biotite

Obsidian

Dark volcanic glass formed from rapidly cooled lava

Pumice

Light extrusive igneous rock with gas bubbles, floats on water

Scoria

Dark extrusive igneous rock denser than pumice, sinks in water

Uses of igneous rocks

Include building materials, concrete, road surfaces, and ornaments

Shearing

Process where rocks slide sideways due to pressure

Recrystallisation

Chemical change in rocks forming new minerals

Tectonic Plates

Massive plates in Earth's crust that can collide or move apart

Metamorphism

Process of forming metamorphic rocks due to heat and pressure

Foliation

Movement of minerals into layers or bands in rocks

Contact Metamorphism

Alteration of rock mostly by heat, often due to hot magma intrusion

Dynamic Metamorphism

Alteration of rock mostly by pressure, occurs in small areas

Ore Mineral

Contains a metal or valuable material, extracted from rocks

Native Metal

Metal found in nature as a pure element

Hydrothermal Fluids

Superheated solutions carrying dissolved minerals

Mining

Process of removing resources from the ground

Processing

Extracting and enriching minerals from ore

Rehabilitation

Restoring mining sites to original or usable conditions

Tailings

Toxic waste materials from mining or processing plants