Geology Lecture Notes Review

Flashcards on Metamorphic Rocks, Plate Tectonics, Earthquakes, Earth Systems, Atoms, Solar System, Mineralogy, Igneous Rocks, Sedimentary Rocks

Parent Rock

The original rock from which a metamorphic rock forms, also known as the protolith.

Metamorphism

The process by which existing rocks are altered by heat, pressure, and chemically active fluids.

Metamorphic Grade

A classification of the intensity of metamorphism, ranging from low-grade to high-grade.

Foliation

A texture characterized by the alignment of mineral grains under directed pressure, resulting in a layered appearance.

Non-Foliated Textures

Metamorphic rocks that do not exhibit foliation, which form under uniform pressure.

Contact Metamorphism

Occurs when rocks are heated by nearby molten magma, creating an aureole of altered rock around the intrusion.

Regional Metamorphism

Associated with large-scale tectonic processes, where rocks are subjected to high pressure and temperature over broad areas.

Hydrothermal Metamorphism

Involves the alteration of rocks by hot, mineral-rich water, often occurring at mid-ocean ridges.

Subduction Zone Metamorphism

Takes place in subduction zones where oceanic plates descend into the mantle, leading to high-pressure, low-temperature conditions.

Impact Metamorphism

Results from the high-pressure shock waves generated by meteorite impacts, creating unique minerals.

Slate

A fine-grained metamorphic rock derived from shale, characterized by excellent cleavage.

Phyllite

A slightly coarser-grained rock than slate, with a shiny appearance due to the presence of micas.

Schist

A medium to coarse-grained rock with pronounced foliation, often containing garnet or other minerals.

Gneiss

A high-grade metamorphic rock with distinct banding due to the segregation of mineral types.

Marble

Formed from limestone, prized for its beauty and used in sculpture and architecture.

Plate Tectonics

The theory explaining the movement of Earth's lithosphere, which is divided into tectonic plates that float on the semi-fluid asthenosphere.

Continental Drift Hypothesis

Proposed that continents were once joined and have since drifted apart, forming the current configuration.

Divergent Boundaries

Areas where tectonic plates move apart, leading to seafloor spreading and the formation of oceanic ridges.

Convergent Boundaries

Regions where plates collide, resulting in mountain building, subduction zones, and volcanic activity.

Transform Boundaries

Locations where plates slide past each other, causing earthquakes along faults.

Hot Spots

Areas of volcanic activity fed by mantle plumes, independent of plate boundaries.

Subduction Zones

Regions where one tectonic plate moves under another, leading to deep ocean trenches and volcanic arcs.

Seafloor Spreading

The process by which new oceanic crust is formed at mid-ocean ridges as tectonic plates pull apart.

Paleomagnetism

The study of the magnetic properties of rocks to understand past movements of tectonic plates and the history of Earth's magnetic field.

Curie Point

The temperature at which certain materials lose their permanent magnetic properties, relevant in understanding magnetic reversals.

Earthquake

A sudden release of energy in the Earth's crust that creates seismic waves, often caused by fault movement.

Hypocenter

The point within the Earth where the earthquake originates.

Epicenter

The point directly above the hypocenter on the Earth's surface.

Seismic Waves

Energy waves generated by earthquakes, including body waves and surface waves.

Magnitude

Measures the energy released during an earthquake.

Intensity

Measures the effects of the earthquake.

Tsunami

A series of ocean waves caused by large underwater disturbances, such as earthquakes.

Seismograph

An instrument that records the motion of the ground during an earthquake, producing a seismogram.

Elastic Rebound Theory

Explains how energy is stored in rocks and released during an earthquake, causing the ground to shake.

Aftershocks

Smaller earthquakes that follow a larger one.

Foreshocks

Earthquakes that occur before the main event, indicating potential seismic activity.

Liquefaction

A phenomenon where saturated soil loses strength during an earthquake, causing buildings to sink or tilt.

Hydrosphere

Encompasses all water on Earth, including oceans, rivers, glaciers, and groundwater.

Atmosphere

The layer of gases surrounding Earth, essential for weather, climate regulation, and protecting life from harmful solar radiation.

Biosphere

The global sum of all ecosystems, where living organisms interact with each other and their environment.

Geosphere

The solid part of Earth, including rocks, minerals, and landforms.

Earth System Science

An interdisciplinary approach that studies the interactions between Earth's spheres.

Rock Cycle

The continuous process of rock formation and transformation, involving igneous, sedimentary, and metamorphic rocks.

Weathering and Erosion

Processes that break down rocks and transport sediments, shaping landscapes and contributing to soil formation.

Volcanism

The eruption of molten rock from beneath the Earth's crust.

Protons

Positively charged particles that define the element.

Neutrons

Neutral particles that stabilize the nucleus by offsetting the repulsive forces between protons.

Electrons

Negatively charged particles that occupy orbitals around the nucleus and are crucial for chemical bonding.

Valence Electrons

The outermost electrons of an atom and play a key role in determining how atoms bond with each other.

Planetesimals

Small rocky or icy bodies that collided and merged to form protoplanets, the building blocks of planets.

Supernova

A massive explosion that disperses heavy elements into space, contributing to the material that forms planets.

Habitable Zone

The region around a star where conditions are just right for liquid water to exist.

Crust

The thin, outermost layer of Earth, divided into continental and oceanic crust.

Mantle

A thick layer beneath the crust, composed of solid rock that behaves plastically over long timescales.

Core

The metallic center of Earth, consisting of a liquid outer core and a solid inner core.

Lithosphere

The rigid outer shell of Earth, composed of the crust and upper mantle, broken into tectonic plates.

Asthenosphere

A partially molten layer that allows tectonic plates to move due to its plastic-like properties.

Mineral

A naturally occurring, inorganic solid with a definite chemical composition and crystalline structure.

Rock

An aggregate of one or more minerals.

Diagnostic Properties

Unique traits that help identify minerals.

Ambiguous Properties

Traits that vary among specimens and are unreliable for identification.

Luster

The way light reflects off a mineral's surface, categorized as metallic or nonmetallic.

Hardness

Measured using the Mohs Hardness Scale, which ranks minerals from 1 (talc) to 10 (diamond).

Streak

The color of the powder left by a mineral when scratched on a streak plate.

Crystal Habit

The external shape of a mineral, influenced by its internal structure.

Cleavage

Refers to a mineral's tendency to break along flat planes.

Fracture

Describes irregular breakage.

Tenacity

Describes a mineral's response to stress, categorized as brittle, malleable, or elastic.

Density

Mass per unit volume.

Rock-forming Minerals

Comprises about two dozen minerals that make up most of Earth's crust.

Economic Minerals

Mined for practical use, either metallic or nonmetallic.

Silicate Minerals

The largest group, characterized by the silicon-oxygen tetrahedron.

Nonsilicate Minerals

Do not contain silicate tetrahedra; main groups include carbonates, oxides, and sulfides.

Placer Deposits

Formed by flowing water that concentrates heavy minerals like gold or diamonds in streambeds.

Secondary Enrichment

A weathering process that concentrates valuable metals closer to the surface.

Disseminated Deposits

Ore minerals scattered throughout the rock.

Vein Deposits

Formed when hydrothermal solutions fill cracks and precipitate minerals.

Igneous Rocks

Form from the cooling and solidification of molten rock (magma or lava).

Intrusive Rocks

Form below the surface.

Extrusive rocks

Form on the surface after a volcanic eruption.

Texture

The appearance of a rock based on crystal size and arrangement.

Pyroclastic Texture

Formed from volcanic fragments ejected during explosive eruptions.

Felsic Composition

High in silica, light in color.

Intermediate Composition

Moderate silica content, gray to light-dark color.

Mafic Composition

Low in silica, high in iron and magnesium.

Ultramafic Composition

Very low silica, very high in iron and magnesium, typically found in the mantle.

Aphanitic Texture

Fine-grained, forms from rapid cooling.

Phaneritic Texture

Coarse-grained, forms from slow cooling.

Porphyritic Texture

Contains two distinct crystal sizes, indicating a complex cooling history.

Vesicular Texture

Contains gas bubbles, indicating explosive eruptions.

Glassy Texture

No crystals formed due to rapid cooling.

Pegmatitic Texture

Extremely coarse-grained, forms from water-rich magmas that cool slowly.

Intrusion

A body of igneous rock formed from magma that crystallizes underground.

Dikes

Vertical intrusions that cut across rock layers.

Sills

Horizontal intrusions that form between layers.

Batholiths

Large, irregularly shaped intrusions, often granite, forming the cores of mountain ranges.

Lava Flows

Different types of lava flows include Aa (rough surface) and Pahoehoe (smooth, ropy surface).

Pyroclastic Materials

Ejected solid fragments during explosive eruptions.

Sedimentary Rocks

Form through processes of deposition, compaction, and cementation.

Compaction

Reduces pore space as overlying pressure increases.