Glossary

Pyrite

Pyrite, or “Fool’s Gold,” is used for sulfur and iron production.

Talc

Talc, the softest mineral, is used in baby powder, cosmetics, ceramics, and plastics.

Gneiss

Gneiss is a durable, banded metamorphic rock used in construction and decoration.

Quartz

Quartz, a silicon dioxide mineral, is used in jewelry and electronics.

Magnetite

Magnetite, an iron oxide with magnetic properties, is used in steel production and catalysts.

Beryl

Beryl is a gemstone mineral, including emerald and aquamarine, and a source of beryllium.

Mica

Mica is a group of silicate minerals with varying compositions mainly in insulation and electronics.

Apatite

Apatite is a calcium phosphate mineral found in various colors, primarily used in fertilizers.

Zircon

Zircon is a durable mineral used in jewelry, geological dating, and ceramics.

Tourmaline

Tourmaline is a colorful boron silicate mineral used as a gemstone and in electronics.

Vanadinite

Vanadinite is a bright red mineral, primarily sourced from lead deposits.

Rhyolite

Rhyolite, a silica-rich volcanic rock, is used in construction and research.

Gypsum

Gypsum, a soft calcium sulfate mineral, is primarily used as plaster or in cement production.

Borax

Borax is a sodium borate used in cleaning and glassmaking.

Scheelite

Scheelite, a calcium tungstate, is the main source of tungsten for tools and alloys.

Sandstone

Sandstone, composed of quartz and feldspar, is used in construction, paving, landscaping, and glassmaking.

Basalt

Basalt is a dark, fine-grained igneous rock used in construction, monuments, and geological studies.

Hematite

Hematite is an iron oxide mineral used for iron ore, pigments, and radiation shielding.

Barite

Barite is a barium sulfate mineral used in drilling, shielding, and paints.

Bauxite

Bauxite is the main aluminum ore, primarily found in Australia.

Galena

Galena is the main ore of lead and silver, used in batteries and shielding.

Muscovite

Muscovite, a mica mineral, is used in insulation, fireproofing, and cosmetics.

Biotite

Biotite is a dark mica mineral used in insulation and geological studies.

Limestone

Limestone, mainly calcium carbonate, is used in construction, cement, and water treatment.

Garnet

Garnet is a group of silicate minerals used as gemstones and abrasives.

Monazite

Monazite, a group of rare earth minerals, is a key source of rare earth elements.

Metamorphic rock with dark red garnet crystals

Chlorite

Chlorite, a green phyllosilicate mineral, is used as a geological indicator and industrial filler.

Feldspar

Feldspar is an aluminum silicate used in ceramics, glass, and construction.

Marble

Marble, a calcium carbonate metamorphic rock, is used in sculpture, architecture, and countertops.

Dolomite

Dolomite is a calcium magnesium carbonate used in construction and agriculture.

Halite

Halite, or rock salt, is a sodium chloride mineral used for seasoning, de-icing, and industry.

Calcite

Calcite is a trigonal calcium carbonate mineral used mainly in construction for making cement.

Pyroxene

Pyroxene, a silicate mineral group found in igneous and metamorphic rocks.

Adamite

Adamite is a rare, colorful orthorhombic mineral prized by collectors for its vibrant crystals.

Descloizite

Descloizite is a lead-zinc vanadate mineral, mainly found in Namibia and Mexico.

Olivine

Olivine, a magnesium iron silicate, is used in gemstones (peridot) and refractory materials.

Diorite

Diorite is a tough igneous rock used in construction, art, and in research.

Amphibole

Amphibole is a diverse mineral group used for geological indicators and as insulation.

Scorodite

Scorodite, a hydrated iron arsenate, is valued for arsenic containment and as a collector’s mineral.

Quartzite

Quartzite, a durable metamorphic rock made of quartz, is used in construction and countertops.

Coal

Coal, mainly carbon, is used for energy and steel production.

Shale

Shale, a fine-grained sedimentary rock, is used for natural gas, cement, and research.

Wulfenite

Wulfenite is a bright orange or yellow mineral, prized by collectors.

Fluorite

Fluorite, a colorful calcium fluoride, is used as flux in steelmaking, glass, and as gemstones.

Kernite

Kernite is a boron-rich mineral used in glassmaking, detergents, and ceramics.

Schist

Schist, a layered metamorphic rock rich in mica and quartz, is often used in construction.

Granite

Granite is a durable igneous rock used in construction, monuments, and countertops.

^AAbyssal Plain

Abyssal plains are large, flat, and nearly featureless regions of the deep ocean floor, located at depths between 3,000 to 6,000 meters. These plains are formed through the slow accumulation of fine sediments, including clay and microscopic organisms, that descend from the ocean surface. The creation of abyssal plains is also influenced by the spreading of oceanic plates, which produces new seafloor. These regions are critical to understanding deep-sea sedimentation processes and the geological history of the ocean basins.

Reference: Craig R. Smith; Fabio C. De Leo; Angelo F. Bernardino; Andrew K. Sweetman; Pedro Martinez Arbizu (2008). “Abyssal food limitation, ecosystem structure and climate change”

^AAccretion

In geology, accretion refers to the process by which material is added to a tectonic plate at convergent boundaries. This material can include sediment, volcanic arcs, and other fragments of crust that are scraped off a subducting plate and attached to the overriding plate, forming an accretionary wedge. Accretion plays a significant role in the growth of continental crust and the formation of mountain ranges.

Reference: Ballard, Robert D. (1988). Exploring our living planet. National Geographic Book Service., National Geographic Society (U.S.) (Rev. ed.). Washington, D.C.: National Geographic Society. ISBN 0-87044-760-2. OCLC 18325626

^AAccretionary Wedge

An accretionary wedge is a large, wedge-shaped mass of sediment and oceanic crust that accumulates at convergent plate boundaries, where one plate is subducted beneath another. The sediments are scraped off the subducting plate and piled onto the overriding plate, forming complex structures of folded and faulted rocks. Accretionary wedges are key in understanding the tectonic evolution of convergent margins and the processes involved in mountain building.

Reference: https://www.usgs.gov/media/images/accretionary-wedge.

^AActive Margin

An active margin is a type of continental margin that is tectonically active, typically characterized by the presence of a convergent plate boundary where an oceanic plate is being subducted beneath a continental plate. Active margins are associated with features such as deep ocean trenches, volcanic arcs, and high seismic activity. They contrast with passive margins, which are tectonically inactive.

Reference: Orme, A. R. “1.10 Tectonism, Climate, and Geomorphology.” Treatise on Geomorphology 1 (2013): 146.

^AAeolian Dune

Description: Aeolian dunes are hills or ridges of sand formed by the wind in desert or coastal environments. The shape and size of aeolian dunes are influenced by wind direction, sand supply, and vegetation. These dunes are significant in the study of sedimentary processes and desert geomorphology, as well as in understanding past climatic conditions.

Reference: https://www.nps.gov/subjects/geology/aeolian-landforms.htm

^AAeolian Processes

Aeolian processes involve the erosion, transport, and deposition of sediments by wind. These processes are most effective in arid environments, where vegetation is sparse, and sediment is loose and dry. Aeolian features include dunes, loess deposits, and desert pavements. Understanding aeolian processes is important for interpreting past climate conditions and predicting future landscape changes in desert regions.

Reference: Lancaster, N. (1995). “Geomorphology of Desert Dunes.” Routledge.

^AAeolianite

Aeolianite is a type of sedimentary rock formed from the lithification of wind-blown (aeolian) sands. These rocks are typically composed of quartz grains and are found in coastal and desert environments. Aeolianites are important indicators of past climatic conditions and wind regimes and are studied to understand sedimentary processes in arid regions.

Reference: Brooke, B. (2001). “The Distribution and Formation of Coastal Aeolianite.” Earth-Science Reviews, 55(1-2), 135-164.

^AAgglomerate

Agglomerate is a coarse, volcanic rock composed of angular fragments of volcanic material that have been welded or cemented together. It forms from explosive volcanic eruptions and is typically found in volcanic settings, such as around vent areas. Agglomerates are important for understanding the eruptive history and dynamics of volcanoes.

Reference: Williams, H., & McBirney, A. R. (1979). Volcanology. Freeman, Cooper & Company.

^AAlbedo

Albedo is a measure of the reflectivity of a surface, expressed as the ratio of reflected radiation from the surface to the incident radiation upon it. In geology, albedo is important in studying Earth’s climate, as surfaces with high albedo (such as ice and snow) reflect most of the solar energy, while those with low albedo (such as forests and oceans) absorb more energy. Albedo effects are crucial in understanding climate change and energy balance on Earth.

Reference: Trenberth, K. E., & Fasullo, J. T. (2010). “Earth’s Global Energy Budget.” Bulletin of the American Meteorological Society, 91(3), 311-324.

^AAleutian Arc

The Aleutian Arc is a volcanic arc located in the northern Pacific Ocean, extending from Alaska to Russia. It is formed by the subduction of the Pacific Plate beneath the North American Plate, creating a chain of active volcanoes. The Aleutian Arc is a prime example of an island arc system and is significant for studying subduction-related volcanic activity, plate tectonics, and associated seismic hazards.

Reference: https://www.usgs.gov/publications/geologic-framework-aleutian-arc-alaska.

^AAlkaline Igneous Rock

Alkaline igneous rocks are a category of igneous rocks that contain higher concentrations of alkali metals (sodium and potassium) relative to silica. These rocks often form in tectonic settings such as continental rifts or hotspots. Examples include nepheline syenite and phonolite. Alkaline rocks are important for understanding mantle processes and the evolution of magmas in extensional tectonic environments.

Reference: https://www.sciencedirect.com/topics/earth-and-planetary-sciences/alkaline-rock

^AAllochthonous

The term allochthonous refers to rocks or sediments that have been transported from their place of origin and deposited in a different location, typically by tectonic forces. In geology, allochthonous units are often contrasted with autochthonous units, which have remained in their place of formation. Allochthonous materials provide insights into the dynamics of tectonic processes, such as thrust faulting and subduction.

Reference: Davis, G. H., & Reynolds, S. J. (1996). Structural Geology of Rocks and Regions. John Wiley & Sons.

^AAlluvial Fan

An alluvial fan is a triangular or fan-shaped deposit of gravel, sand, and smaller materials, created where a fast-flowing stream flattens out. Typically found at the base of mountain ranges, alluvial fans form when a stream’s gradient decreases, leading to sediment deposition. They are common in arid and semi-arid regions and are significant in interpreting past climatic and geological conditions, as well as in groundwater studies due to their porous nature.

Reference: Blair, T. C., & McPherson, J. G. (1994). “Alluvial Fans and Their Natural Distinction from Rivers Based on Morphology, Hydraulic Processes, Sedimentary Processes, and Facies Assemblages.” Journal of Sedimentary Research, 64(3), 450-489.

^AAmmonite

Ammonites are an extinct group of marine mollusk animals that existed from the Devonian to the Cretaceous period. Their spiral shells are commonly found as fossils and are used as index fossils to date the age of the rock layers in which they are found. Ammonites are important in paleontology for understanding the evolution of marine life and the environmental conditions of ancient oceans.

Reference: Monks, N., & Palmer, P. (2002). Ammonites. Smithsonian Books.

^AAmphitheater Valley

An amphitheater valley is a steep-walled, U-shaped valley that resembles an amphitheater in shape, often formed by the headward erosion of streams or glaciers. These valleys are common in mountainous regions and provide important insights into the processes of erosion, weathering, and the geomorphological evolution of landscapes.

Reference: Thornbury, W. D. (1965). Regional Geomorphology of the United States. John Wiley & Sons.

^AAnabranch

An anabranch is a section of a river or stream that diverts from the main channel and rejoins it downstream. Anabranches are common in river systems with low gradients and are often associated with braided rivers. The formation and evolution of anabranches are important for understanding river dynamics, sediment transport, and floodplain development.

Reference: Brierley, G. J., & Fryirs, K. A. (2005). Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing.

^AAnaerobic Environment

An anaerobic environment is one that lacks oxygen, which can significantly affect the types of chemical reactions that occur, as well as the types of organisms that can survive. In geology, anaerobic conditions are often found in deep sediments, swamps, and some groundwater systems. These environments are important in the study of biogeochemical cycles, particularly the formation of organic-rich sediments and fossil fuels.

Reference: Berner, R. A. (1981). “A New Geochemical Classification of Sedimentary Environments.” Journal of Sedimentary Research, 51(2), 359-365.

^AAnomalous Magnetic Field

An anomalous magnetic field refers to deviations in Earth’s magnetic field from the expected normal pattern. These anomalies can be caused by variations in the Earth’s crust, such as the presence of different types of rocks, or by external factors like solar wind. Studying these anomalies helps geophysicists understand the structure of the Earth’s crust and mantle, as well as past movements of tectonic plates.

Reference: Dyment, J., & Arkani-Hamed, J. (1998). “Geophysical Interpretation of Anomalous Magnetic Fields.” Geophysical Journal International, 133(2), 435-456.

^AAnthracite

Anthracite is the highest grade of coal, known for its high carbon content, low impurities, and high energy density. It is formed under conditions of high temperature and pressure, typically in geologically older formations. Anthracite is an important fuel source and has been extensively mined for its energy-rich properties, particularly in regions with significant industrial history.

Reference: Speight, J. G. (2012). The Chemistry and Technology of Coal. CRC Press.

^AAnthropocene

The Anthropocene is a proposed geological epoch that denotes the current period in Earth’s history, characterized by the significant impact of human activities on the planet’s geology and ecosystems. The term emphasizes the pervasive influence of humans on climate, biodiversity, and natural processes, potentially leaving a distinct stratigraphic signature in the rock record. The formal recognition of the Anthropocene is still under scientific debate.

Reference: Crutzen, P. J. (2006). “The Anthropocene.” In Earth System Science in the Anthropocene (pp. 13-18). Springer.

^AAnticline

An anticline is a type of fold in sedimentary strata that is arch-like in shape, with its oldest rocks located at the core of the fold. The limbs of an anticline dip away from the center, creating a convex-upward structure. Anticlines are important in petroleum geology because they can serve as traps for oil and natural gas, accumulating hydrocarbons in the crest of the fold.

Reference: Twiss, R. J., & Moores, E. M. (2007). Structural Geology. W.H. Freeman and Company.

^AAnticlinorium

An anticlinorium is a large-scale anticline or a series of anticlinal folds that together form a complex, mountainous structure. These structures are common in regions that have undergone significant compressional tectonic forces, such as during the formation of mountain ranges. The study of anticlinoria is important in understanding the large-scale tectonic evolution of orogenic belts.

Reference: Davis, G. H., & Reynolds, S. J. (1996). Structural Geology of Rocks and Regions. John Wiley & Sons.

^AAntiform

An antiform is a fold that has the shape of an arch, but unlike an anticline, it does not necessarily have the oldest rocks at its core. The term is used when the age relationships between the strata are unknown or irrelevant. Antiforms are important in the study of fold structures and tectonic deformation, providing information on the stresses and forces that have shaped a region’s geology.

Reference: Ramsay, J. G. (1967). Folding and Fracturing of Rocks. McGraw-Hill.

^NArchives: Glossary

Nappe fold structure refers to the large-scale folds associated with the formation of nappes during compressional tectonics. These structures are key features in understanding the deformation processes involved in orogeny and the tectonic evolution of mountain belts.

Reference: Ramsay, J. G., & Huber, M. I. (1987). “The Techniques of Modern Structural Geology, Volume 2: Folds and Fractures.” Academic Press.