Earth Materials and Processes – Rocks and Rock Cycle

Vocabulary flashcards covering key terms related to rock types, textures, formation processes, and the rock cycle.

The scientific study of rocks, their origin, composition, and structure.

Petrology

A naturally occurring aggregate of minerals, rock fragments, or organic matter.

Rock

The size, shape, and arrangement of mineral grains or crystals within a rock.

Texture (rocks)

Composition (rocks)

The mineral, chemical, and sometimes fossil content that makes up a rock.

The continuous processes that form, break down, and re-form rocks through melting, crystallization, weathering, lithification, and metamorphism.

Rock Cycle

Rock formed by the solidification of molten magma or lava.

Igneous Rock

Igneous rock that solidifies slowly below Earth’s surface, producing large crystals (e.g., granite, peridotite).

Intrusive (Plutonic) Igneous Rock

Igneous rock that solidifies quickly at or near the surface, producing fine crystals or glass (e.g., basalt, obsidian).

Extrusive (Volcanic) Igneous Rock

Light-colored igneous rocks rich in feldspar and silica.

Felsic

Dark-colored igneous rocks rich in magnesium, iron, and calcium.

Mafic

Igneous rocks with a composition between mafic and felsic.

Intermediate (igneous)

Igneous rocks composed chiefly of mafic minerals with very low silica content.

Ultramafic

Fine-grained igneous texture where crystals are too small to see unaided; forms from rapid cooling.

Aphanitic Texture

Coarse-grained igneous texture with large, visible crystals; forms from slow cooling.

Phaneritic Texture

Igneous texture with large crystals (phenocrysts) embedded in a fine-grained matrix.

Porphyritic Texture

Igneous texture that looks like colored glass, containing no visible crystals (e.g., obsidian).

Glassy Texture

Fragmental igneous texture produced by explosive volcanic eruptions.

Pyroclastic Texture

A coarse-grained, felsic, intrusive igneous rock composed mainly of quartz and feldspar.

Granite

A fine-grained, mafic, extrusive igneous rock common in oceanic crust.

Basalt

A volcanic glass with a glassy texture formed by rapid cooling of lava.

Obsidian

A coarse-grained, ultramafic, intrusive igneous rock rich in olivine.

Peridotite

A pyroclastic rock composed of volcanic ash and fragments ejected during explosive eruptions.

Tuff

Rock formed from pre-existing rock transformed by heat, pressure, and/or chemically active fluids.

Metamorphic Rock

The process of transforming rock type into another

Metamorphism

Metamorphism caused mainly by heat from nearby magma, producing non-foliated rocks such as hornfels.

Contact Metamorphism

Large-scale metamorphism dominated by pressure during mountain-building, producing foliated rocks like schist and gneiss.

Regional Metamorphism

Planar alignment of mineral grains or structural features within a metamorphic rock.

Foliation

Metamorphic rock with layered or banded appearance due to aligned minerals (e.g., slate, schist).

Foliated Rock

Metamorphic rock lacking foliation, often composed of one or few minerals (e.g., marble, quartzite).

Non-foliated Rock

A hard, non-foliated metamorphic rock formed from sandstone.

Quartzite

A non-foliated metamorphic rock formed from limestone or dolostone; composed mainly of calcite.

Marble

A fine-grained, foliated metamorphic rock formed from shale; splits into thin sheets.

Slate

A low- to medium-grade foliated metamorphic rock with a silky sheen, between slate and schist.

Phyllite

Rock formed from accumulated sediments or biological/chemical precipitates, often showing layering.

Sedimentary Rock

The breakdown of rocks at Earth’s surface by physical or chemical processes.

Weathering

Movement of weathered material by water, wind, ice, or gravity.

Transportation (sediments)

The settling or laying down of transported sediments.

Deposition

The conversion of loose sediment into solid sedimentary rock through compaction and cementation.

Lithification

Process by which overlying pressure squeezes sediments, reducing pore space.

Compaction

Process in which dissolved minerals precipitate between sediment grains, binding them together.

Cementation

Sedimentary rock composed of fragments of pre-existing rocks (e.g., sandstone, conglomerate).

Clastic Sedimentary Rock

Sedimentary rock formed from accumulated plant or animal remains (e.g., limestone, coal).

Biological Sedimentary Rock

Sedimentary rock formed by precipitation of minerals from solution (e.g., rock salt).

Chemical Sedimentary Rock