Glossary

Quartzite

Fact Sheet:

Chemical Composition: Primarily composed of quartz (SiO₂)
Hardness: 7 on the Mohs scale
Crystal System: Metamorphic rock, non-foliated
Color Varieties: White, gray, pink, red, yellow, blue, green, and purple
Major Localities: United States, Brazil, Norway, South Africa, India, and Canada
Common Uses: Construction material, decorative stone, countertops, road ballast, and architectural applications

Introduction: Quartzite is a hard, durable metamorphic rock primarily composed of quartz that forms from the recrystallization of sandstone under intense heat and pressure. This process transforms the original quartz grains in the sandstone into a dense, interlocking mosaic of quartz crystals. Quartzite’s ...

^BBoulder Field

A boulder field is an extensive area covered by large, weathered rocks, typically found at high elevations or in glacial environments. These fields are formed by processes such as frost weathering, glacial action, and mass wasting. Boulder fields are important for understanding the geomorphological processes that shape mountainous and polar regions.

Reference: Fahey, B. D., & Lefebure, T. (1988). “Boulder Fields and the Morphology of the Southern Alps.” New Zealand Journal of Geology and Geophysics, 31(4), 435-446.

^BBouma Sequence

The Bouma sequence is a characteristic set of sedimentary structures found in turbidite deposits, consisting of five distinct layers representing different flow regimes. It is used to interpret depositional environments in deep marine settings, particularly in the context of submarine fan systems and sediment gravity flows.

Reference: Bouma, A. H. (1962). Sedimentology of Some Flysch Deposits: A Graphic Approach to Facies Interpretation. Elsevier.

^BBraided River

A braided river is characterized by multiple, interconnected channels that weave around bars and islands of sediment. These rivers typically form in areas with a high sediment load and variable water flow, such as glacial meltwater streams. Braided rivers are important in the study of fluvial processes, sediment transport, and landscape evolution.

Reference: Leopold, L. B., & Wolman, M. G. (1957). “River Channel Patterns: Braided, Meandering, and Straight.” U.S. Geological Survey Professional Paper 282-B.

^BBuried Soil

Buried soils, or paleosols, are ancient soil horizons that have been preserved beneath layers of sediment or volcanic deposits. These soils provide valuable information about past climates, vegetation, and environmental conditions, serving as important markers in stratigraphy and the study of Earth’s history.

Reference: Retallack, G. J. (2001). Soils of the Past: An Introduction to Paleopedology. Wiley-Blackwell.

^BBuried Valley

A buried valley is an ancient river valley that has been filled with sediment and buried beneath newer layers of material. These valleys are important in hydrogeology because they often serve as aquifers, providing significant groundwater resources. The study of buried valleys can also reveal information about past river systems and climate conditions.

Reference: Eyles, N., & Arnott, R. W. C. (1986). The Geological Record of Glaciation.

^BButte

A butte is an isolated hill with steep, often vertical sides and a flat top, formed by erosion of the surrounding land. Buttes are remnants of larger rock structures, such as mesas or plateaus, that have been worn away over time. They are common in arid and semi-arid regions and are significant in understanding erosion processes and landscape evolution.

Reference: Twidale, C. R. (2007). Desert Geomorphology. Cambridge University Press.

^CCaldera

A caldera is a large, basin-shaped volcanic depression that forms when a volcano collapses after the emptying of a magma chamber during an explosive eruption. Calderas are much larger than typical volcanic craters, often several kilometers in diameter. They are significant in understanding volcanic processes, the dynamics of magma chambers, and the potential hazards associated with large-scale eruptions.

Reference: Lipman, P. W. (1997). “Subsidence of Ash-Flow Calderas: Relation to Caldera Size and Magma-Chamber Geometry.” Bulletin of Volcanology, 59(3), 198-218.

^CCaliche

Caliche is a hardened deposit of calcium carbonate that forms in arid and semi-arid regions within the soil or at the surface. It can act as a cement, binding together soil particles and forming a hard, impervious layer. Caliche is significant in soil science and desert geomorphology, as it affects soil development, water infiltration, and plant growth.

Reference: Gile, L. H., Hawley, J. W., & Grossman, R. B. (1966). “Morphological and Genetic Sequences of Caliche Formation in Desert Soils.” Soil Science, 101(5), 347-360.

^CCarbon Sequestration

Carbon sequestration refers to the process of capturing and storing atmospheric carbon dioxide in order to mitigate climate change. This can occur naturally, through processes like photosynthesis and the formation of carbonate minerals, or artificially, through techniques like carbon capture and storage (CCS). Carbon sequestration is significant in efforts to reduce greenhouse gas concentrations and combat global warming.

Reference: Lal, R. (2008). “Carbon Sequestration.” Philosophical Transactions of the Royal Society B: Biological Sciences, 363(1492), 815-830.

^CCarbonate Compensation Depth (CCD)

The carbonate compensation depth (CCD) is the depth in the ocean below which calcium carbonate (CaCO3) dissolves more rapidly than it accumulates, preventing the formation of carbonate sediments. This depth varies with the acidity, temperature, and pressure of the seawater. The CCD is significant in paleoceanography and sedimentology, as it influences the distribution of carbonate sediments on the ocean floor.

Reference: Berger, W. H., & Winterer, E. L. (1974). “Plate Stratigraphy and the Fluctuating Carbonate Line.” Pelagic Sediments: On Land and Under the Sea. International Association of Sedimentologists Special Publication No. 1.

^CCarbonate Platform

A carbonate platform is a sedimentary body that forms in shallow, warm marine environments and is primarily composed of carbonate minerals such as limestone and dolostone. These platforms are typically associated with coral reefs and other biological activity. Carbonate platforms are crucial in the study of sedimentology, paleoenvironments, and petroleum geology due to their potential as hydrocarbon reservoirs.

Reference: Schlager, W. (1992). “Sedimentology and Sequence Stratigraphy of Carbonate Platforms.” Marine Geology, 110(1-2), 163-174.

^CCataclasite

Cataclasite is a type of fault rock formed by mechanical fragmentation and frictional grinding during faulting, without significant recrystallization. It is typically found in fault zones and is characterized by a fine-grained matrix surrounding larger, angular fragments of rock. Cataclasites are important in understanding fault mechanics and the deformation of the Earth’s crust.

Reference: Sibson, R. H. (1977). “Fault Rocks and Fault Mechanisms.” Journal of the Geological Society, 133(3), 191-213.

^CCatastrophism

Catastrophism is the geological doctrine that Earth’s history has been shaped primarily by sudden, short-lived, and violent events, such as volcanic eruptions, earthquakes, and floods. This contrasts with the principle of uniformitarianism, which emphasizes gradual processes. While modern geology recognizes the importance of both catastrophic events and gradual processes, catastrophism was historically significant in debates about Earth’s history and the development of geological theories.

Reference: Oreskes, N. (1999). The Rejection of Continental Drift: Theory and Method in American Earth Science. Oxford University Press.

^CCementation

Cementation is the process by which minerals precipitate from groundwater and fill the spaces between sediment grains, binding them together into a solid rock. This process is a key stage in the lithification of sedimentary rocks and is significant in the study of diagenesis and the formation of sedimentary structures.

Reference: Boggs, S. (2009). Petrology of Sedimentary Rocks. Cambridge University Press.

^CChatter Marks

Chatter marks are small, curved fractures found on glaciated rock surfaces, formed by the jerky movement of a glacier over bedrock. These marks are typically crescent-shaped and provide important clues about the direction of glacial movement and the nature of glacial erosion. Chatter marks are studied in the field of glacial geomorphology.

Reference: Boulton, G. S. (1974). “Processes and Patterns of Subglacial Sedimentation: A Theoretical Approach.” Geological Society of America Bulletin, 85(3), 439-445.

^CChelation

Chelation in geology refers to the process by which metal ions are bound to organic molecules, forming stable, water-soluble complexes. This process plays a critical role in soil chemistry, the mobility of metals in the environment, and the formation of ore deposits. Chelation is important in understanding biogeochemical cycles and the behavior of trace elements in soils and sediments.

Reference: Sposito, G. (1989). The Chemistry of Soils. Oxford University Press.

^CChert

Chert is a hard, fine-grained sedimentary rock composed primarily of microcrystalline quartz (silica). It often forms in marine environments as nodules or layers within limestone or chalk and can also be a product of diagenetic processes. Chert is significant in geology for its use in reconstructing past marine environments and as a source of ancient tool-making material.

Reference: Hein, J. R., & Parrish, J. T. (1987). “Distribution of Siliceous Deposits in Space and Time.” Paleogeography, Paleoclimatology, Paleoecology, 60(1-2), 1-7.

^CCirque

A cirque is a bowl-shaped, amphitheater-like depression eroded into a mountain by a glacier. Cirques are typically found at the head of a glacial valley and are the starting point for glacier formation. The study of cirques is important in understanding glacial processes, alpine geomorphology, and the climatic conditions that lead to glacier formation.

Reference: Benn, D. I., & Evans, D. J. A. (2010). Glaciers and Glaciation. Routledge.

^CClastic Rock

Clastic rocks are sedimentary rocks composed of fragments, or clasts, of pre-existing minerals and rocks. These fragments are transported by water, wind, or ice and deposited in different environments, where they are lithified into rock. Clastic rocks, such as sandstone, shale, and conglomerate, are key in reconstructing past environments and understanding sedimentary processes.

Reference: Boggs, S. (2009). Petrology of Sedimentary Rocks. Cambridge University Press.

^CClathrate

Clathrates, or gas hydrates, are crystalline structures where gas molecules, typically methane, are trapped within a lattice of water ice. They are found in permafrost regions and beneath the ocean floor. Clathrates are significant in studies of climate change, as they represent a potential source of methane, a potent greenhouse gas, which could be released if the clathrates destabilize due to warming temperatures.

Reference: Sloan, E. D., & Koh, C. A. (2008). Clathrate Hydrates of Natural Gases. CRC Press.

^CCleavage

Cleavage is a type of foliation in metamorphic rocks, characterized by the tendency of the rock to split along parallel planes. It is typically associated with low-grade metamorphism and is often found in slate and phyllite. Cleavage planes form as a result of directed pressure during deformation, making them significant in understanding the stress and strain history of a rock.

Reference: Passchier, C. W., & Trouw, R. A. J. (2005). Microtectonics. Springer.

^CCliff Retreat

Cliff retreat is the process by which coastal or riverine cliffs erode and move landward over time. This process can be driven by wave action, weathering, and mass wasting. Cliff retreat is important in understanding coastal dynamics, erosion rates, and the impact of sea-level rise on coastal landscapes.

Reference: Sunamura, T. (1992). Geomorphology of Rocky Coasts. Wiley.

^CColumnar Basalt

Columnar basalt is a type of rock formation characterized by hexagonal columns that result from the cooling and contraction of basaltic lava. These columns typically form in parallel arrays and are often found in volcanic regions. Columnar basalt formations are significant in the study of volcanic processes and the cooling behavior of lava.

Reference: Goehring, L., Morris, S. W., & Lin, Y. (2006). “Granular-Fluid Behavior in Columnar Basalt Formation.” Physical Review Letters, 97(9), 095503.

^YArchives: Glossary

The Yazoo Backwater Area is a floodplain region in the Mississippi Delta that experiences frequent flooding due to the overflow of the Mississippi and Yazoo Rivers. This area is significant in hydrology and flood management for understanding the dynamics of river flooding, the impact on agriculture and infrastructure, and the strategies for flood control in deltaic regions.

Reference: Autin, W. J. (2005). “The Mississippi River: A Geomorphological Perspective.” Geomorphology, 70(3-4), 293-314.