Planet Earth Flashcards
Oblate Spheroid
The shape of Earth, slightly flattened at the poles and bulging at the equator due to its rotation
Hemisphere
Half of the Earth, divided into Northern and Southern by the equator or Eastern and Western by the Prime Meridian
Magnetic Field
The invisible field generated by movements in Earth’s molten outer core, protecting the planet from solar wind and radiation
Axis
An imaginary line about which the Earth rotates, tilted at 23.5* relative to the plane of its orbit
Rotation
The spinning of Earth on its axis, taking ~24 hours to complete and causing day and night
Revolution
The orbiting of Earth around the Sun, taking ~365.25 days and causing seasonal changes
Rock
A naturally occurring solid aggregate of minerals of mineraloids
Temperature
In geology, it plays a critical role in rock formation, especially igneous rocks. High temperatures melt rock into magma, which cools to form igneous rocks
Pressure
Increases with depth in the Earth, aiding in the formation of metamorphic rocks and affecting the crystallization of minerals in igneous rocks
Water
Influences rock formation by lowering the melting point of minerals, aiding magma formation, and contributing to chemical weathering processes
Rock Composition
The mineral makeup of a rock, determining its properties and classification
Pluton
An intrusive igneous rock body that solidifies beneath Earth’s surface
Granite
A coarse-grained intrusive rock composed mainly of quartz, feldspar, and mica
Pumice
A lightweight, porous volcanic rock formed during explosive eruptions
Peridotite
A dense, coarse-grained igneous rock rich in olivine, thought to make up much of the mantle
Sandstone
A sedimentary rock composed mainly of sand-sized particles or mineral grains
Physical Weathering
The mechanical breakdown of rocks into smaller pieces without changing their chemical composition
Chemical Weathering
The decomposition of rocks through chemical reactions, often involving water and atmospheric gases
Lithification
The process of turning sediments into solid rock through compaction and cementation
Metamorphism
The alteration of rocks by heat, pressure, or chemically active fluids
Regional Metamorphism
Metamorphism affecting large areas of the crust, typically associated with mountain-building
Contact Metamorphism
Localized metamorphism caused by heat from nearby magma or lava
Mineral
A naturally occurring, inorganic solid with a specific chemical composition and crystalline structure
Rock Cycle
A continuous process where rocks transition between igneous, sedimentary, and metamorphic forms
Igneous Rocks
Formed from cooled magma or lava; classified by texture and mineral composition
Sedimentary Rocks
Formed by the accumulation and cementation of sediments; often found in strata
Metamorphic Rocks
Rocks transformed by heat and pressure, altering their structure and mineral composition
Constructive Forces
Processes like volcanic eruptions and mountain building that create new landforms
Destructive Forces
Processes like erosion and weathering that break down and reshape landforms
Mineral Identification
Techniques to identify minerals based on properties like hardness, luster, streak, and cleavage
Earth’s Geological Past
The history of Earth as recorded in rock layers, fossils, and geological events
