Geology Terms Flashcards

Questions and Answers

What is an abyssal plain?

Flat or very gently sloping areas of the deep ocean basin floor.

What is accretion?

A process by which material is added to a tectonic plate.

What is an achnelith?

A small, glassy volcanic bomb that may have sphere, dumbbell, or droplet shapes.

What are acid rocks?

Rocks that have progressively increasing SiO2 content, categorized into ultrabasic, basic, intermediate, and acid. Signup and view all the answers

What is an agglomerate?

An indurated rock built of large angular rock fragments embedded in an ashy matrix. Signup and view all the answers

What is albite?

The end member of the plagioclase group of minerals, ideally consisting of silicate of Sodium and Aluminium. Signup and view all the answers

What are alkaline rocks?

Rocks characterized by a high content of Na2O and K2O relative to other oxides. Signup and view all the answers

What does allochthonous mean?

Fossils, sediments, or rocks formed elsewhere and transported to their current location. Signup and view all the answers

What is an alluvial fan?

A fan-shaped deposit formed where a fast-flowing stream flattens and slows, spreading onto a flatter plain. Signup and view all the answers

What is alluvium?

Soil or sediments deposited by a river or other running water. Signup and view all the answers

What are amphiboles?

An important group of dark-colored rock-forming silicates, including hornblende. Signup and view all the answers

What is amphibolite?

A crystalline, coarse-grained rock containing amphibole, feldspar, and frequently garnet. Signup and view all the answers

What does amygdaloidal refer to?

Rocks containing amygdules formed by gas bubbles filled with secondary minerals. Signup and view all the answers

What is anatexis?

Melting of pre-existing rock. Signup and view all the answers

What is andalusite?

A crystalline form of aluminium silicate formed during contact metamorphism of argillaceous rocks. Signup and view all the answers

What is andesite?

A fine-grained igneous rock of intermediate composition. Signup and view all the answers

What is an angular unconformity?

An unconformity where younger strata overlie an erosion surface on tilted or folded layered rock. Signup and view all the answers

What is anorthite?

The lime-rich end of the plagioclase group of minerals, silicate of calcium and aluminium. Signup and view all the answers

What is an anticline?

An arched fold in which the layers dip away from the axis. Signup and view all the answers

What does aphanic refer to?

A texture of carbonate sedimentary rocks characterized by individual crystals or clastic grains < 0.01mm. Signup and view all the answers

What does aphanitic refer to?

The texture of igneous rock in which crystalline components are not distinguishable by the naked eye. Signup and view all the answers

What is aplogranite?

A light-colored rock of granitic texture mainly consisting of alkali feldspar and quartz. Signup and view all the answers

What is the aragonite sea?

A sea that contains aragonite and high-magnesium calcite as the primary inorganic carbonate precipitates. Signup and view all the answers

What does arenaceous refer to?

Sediments that consist essentially of sand grains, primarily quartz and rock fragments. Signup and view all the answers

What is arenite?

A general term for consolidated sedimentary rock composed of sand-sized fragments. Signup and view all the answers

Study Notes

Geology Terms Study Notes

Abyssal Plain: Characterized by flat or gently sloping areas found on the deep ocean basin floor, representing some of the Earth's most stable and extensive geological features.
Accretion: Refers to the process where material is gradually added to a tectonic plate, contributing to geological formations and growth.
Achnelith: A type of volcanic bomb with small, glassy characteristics, appearing in shapes such as spheres, dumbbells, and droplets, indicative of very liquid magma during eruptions.
Acid Rocks: A classification of igneous rocks defined by increasing silica (SiO2) content, which ranges from ultrabasic to basic, intermediate, and acid.
Agglomerate: Indurated rock formed from large angular fragments embedded in an ashy matrix, typically resulting from explosive volcanic events, especially around volcanic vents.
Albite: A member of the plagioclase mineral group, ideally composed of sodium and aluminum silicate, often containing small amounts of potassium and calcium.
Alkaline Rocks: Distinctive for high concentrations of sodium oxide (Na2O) and potassium oxide (K2O), these rocks span from ultrabasic to acid compositions, with notable presence in acid-intermediate ranges.
Allochthonous: Refers to fossils, sediments, or rocks that originated elsewhere and were transported to their current location, often exemplified by large blocks of rock displaced by low-angle thrust faulting.
Alluvial Fan: A fan-shaped sediment deposit created when fast-moving streams slow down and spread onto flatter terrain, commonly found at canyon exits.
Alluvium: Soil or sediment deposited by a flowing river or water body, essential in the formation of fertile land and landscapes.
Amphiboles: A significant group of dark-colored silicate minerals that are crucial for the formation of various igneous and metamorphic rocks, with hornblende being the most common.
Amphibolite: A coarse-grained, crystalline rock primarily containing amphibole minerals, typically formed through the regional metamorphism of basic igneous rocks and lacking foliation.
Amygdaloidal: Describes volcanic rocks containing amygdules, which form when gas bubbles in lava are filled with secondary minerals such as calcite or quartz.
Anatexis: The process involving the melting of pre-existing rocks, significant in understanding the origins of various metamorphic and igneous formations.
Andalusite: A form of aluminum silicate mineral that is commonly produced during contact metamorphism of clay-rich rocks.
Andesite: A type of fine-grained igneous rock with intermediate composition, mainly consisting of plagioclase feldspar and ferromagnesian minerals.
Angular Unconformity: A geological feature where younger rock layers overlie an eroded surface on tilted or folded older rock layers, indicating a historical gap in deposition.
Anorthite: The calcium and aluminum silicate mineral forming the lime-rich part of the plagioclase series, commonly found in basic igneous rocks that have undergone contact metamorphism.
Anticline: A geological structure characterized by an arched fold with layers that dip away from the axial plane, often associated with oil and gas reservoirs.
Aphanic: Refers to the texture of carbonate sedimentary rocks where individual crystals or grains are less than 0.01 mm in size, typically indicating rapid sediment accumulation.
Aphanitic: Describes igneous rock textures where crystalline components are not visible to the naked eye, inclusive of both microcrystalline and cryptocrystalline textures.
Aplogranite: A light-colored rock with a granitic texture, primarily composed of alkali feldspar and quartz, sometimes containing biotite and muscovite.
Aragonite Sea: A term used to describe marine environments characterized by the precipitation of aragonite and high-magnesium calcite as primary carbonate minerals.
Arenaceous: Pertaining to sediments that consist primarily of sand grains, including various formations like conglomerates and sandstones, with particle sizes ranging from 2 mm to 1/16 mm.
Arenite: General term for sedimentary rock composed of sand-sized particles, known for being well-sorted and referred to as "clean" sandstone.

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Test your knowledge with these geology terms flashcards. From abyssal plains to acid rocks, challenge yourself on critical concepts in Earth sciences. Great for students and enthusiasts alike!