Glossary

Gypsum

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

^WWave Ripples

Wave ripples are small, symmetrical ridges and troughs formed on the surface of sedimentary deposits by the action of oscillatory waves. These ripples are significant in sedimentology for understanding the energy conditions of depositional environments, the direction of wave movement, and the interpretation of ancient marine and lacustrine settings.

Reference: Reineck, H.-E., & Singh, I. B. (1980). “Depositional Sedimentary Environments.” Springer-Verlag.

^WWave-Cut Cliff

A wave-cut cliff is a steep, vertical or near-vertical rock face formed by the erosive action of waves at the base of a coastal landform. Wave-cut cliffs are significant in coastal geomorphology for understanding the processes of marine erosion, the retreat of coastlines, and the formation of coastal features such as wave-cut platforms.

Reference: Trenhaile, A. S. (1987). “The Geomorphology of Rock Coasts.” Clarendon Press.

^WWave-Dominated Delta

A wave-dominated delta is a type of delta where wave action is the dominant force shaping the deltaic deposits, resulting in a smooth, arcuate shoreline and the redistribution of sediments along the coast. Wave-dominated deltas are significant in coastal geomorphology for understanding the interplay between fluvial and marine processes in delta formation.

Reference: Galloway, W. E. (1975). “Process Framework for Describing the Morphologic and Stratigraphic Evolution of Deltaic Depositional Systems.” Deltas: Models for Exploration, 87-98.

^WWeathering

Weathering is the process by which rocks and minerals are broken down into smaller particles by physical, chemical, and biological processes. Weathering is significant in geology for understanding the formation of soil, the breakdown of rocks, and the role of weathering in landscape evolution and the rock cycle.

Reference: White, A. F., & Brantley, S. L. (1995). “Chemical Weathering Rates of Silicate Minerals.” Reviews in Mineralogy and Geochemistry, 31(1), 1-22.

^WWell Graded Sediment

Well-graded sediment refers to a sediment deposit that contains a wide range of particle sizes, often resulting in a dense, tightly packed structure. Well-graded sediments are significant in engineering geology and sedimentology for understanding the stability of sediments, the processes of sediment transport, and the design of foundations and embankments.

Reference: Holtz, R. D., Kovacs, W. D., & Sheahan, T. C. (2011). “An Introduction to Geotechnical Engineering.” Prentice Hall.

^WWell Logging

Well logging is the process of recording and analyzing the physical, chemical, and structural properties of rocks and fluids encountered in a borehole. Well logs are significant in petroleum geology, hydrogeology, and engineering for assessing the subsurface geology, evaluating potential resources, and guiding drilling operations.

Reference: Rider, M. H. (1996). “The Geological Interpretation of Well Logs.” Whittles Publishing.

^WWell Sorted Sediment

Well-sorted sediment is a deposit in which the particles are of relatively uniform size, often resulting from the action of wind or water that selectively transports and deposits particles of similar size. Well-sorted sediments are significant in sedimentology for understanding the energy conditions of depositional environments, the processes of sediment transport, and the formation of sedimentary structures.

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

^WWellhead Protection

Wellhead protection involves managing and protecting the land area surrounding a wellhead to prevent contamination of the groundwater source. This concept is significant in environmental science and hydrogeology for ensuring the safety of drinking water supplies, preventing groundwater pollution, and managing land use near wells.

Reference: Todd, D. K., & Mays, L. W. (2005). “Groundwater Hydrology.” John Wiley & Sons.

^WWilsonian Cycle

The Wilsonian cycle describes the cyclical opening and closing of ocean basins caused by plate tectonics, leading to the formation and breakup of supercontinents. This concept is significant in tectonics for understanding the long-term evolution of the Earth’s lithosphere, continental drift, and the processes driving the assembly and fragmentation of supercontinents.

Reference: Wilson, J. T. (1966). “Did the Atlantic Close and Then Re-Open?” Nature, 211(5050), 676-681.

^WWind Abrasion

Wind abrasion is the process by which wind-driven particles, such as sand, erode and polish the surfaces of rocks and other materials. This process is significant in desert geomorphology for understanding the formation of ventifacts, yardangs, and other wind-eroded features, as well as the long-term impact of wind on landscapes.

Reference: Greeley, R., & Iversen, J. D. (1987). “Wind as a Geological Process: On Earth, Mars, Venus and Titan.” Cambridge University Press.

^WWind Gap

A wind gap is a dry pass or notch in a ridge or mountain range, formed by the erosion of a river or stream that has since been diverted or captured. Wind gaps are significant in geomorphology for understanding the history of river drainage systems, stream capture, and landscape evolution.

Reference: Bishop, P. (1995). “Drainage Rearrangement by River Capture, Beheading and Diversion.” Progress in Physical Geography, 19(4), 449-473.

^WWinnowing

Winnowing is the process by which fine particles are removed from a sedimentary deposit by wind or water, leaving behind coarser material. Winnowing is significant in sedimentology for understanding the sorting of sediments, the formation of certain sedimentary structures, and the interpretation of past depositional environments.

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

^WWorm Burrow

Worm burrows are trace fossils left by the burrowing activity of worms in soft sediments, often preserved in sedimentary rocks. These burrows are significant in ichnology and paleoenvironmental studies for understanding the behavior of ancient organisms, the conditions of sediment deposition, and the interpretation of past environments.

Reference: Seilacher, A. (2007). “Trace Fossil Analysis.” Springer.

^XX-ray Absorption Coefficient

The X-ray absorption coefficient is a measure of how easily a material absorbs X-rays, which is used to determine the composition and density of materials in X-ray imaging techniques. This coefficient is significant in geophysics, mineralogy, and materials science for understanding the properties of rocks, minerals, and other materials in non-destructive testing and imaging.

Reference: Jenkins, R. (1999). “X-ray Fluorescence Spectrometry.” Wiley-Interscience.

^XX-ray Absorption Spectroscopy (XAS)

X-ray absorption spectroscopy (XAS) is a technique used to study the electronic structure and local atomic environment of materials by measuring the absorption of X-rays as a function of energy. XAS is significant in mineralogy and geochemistry for understanding the oxidation states, coordination chemistry, and bonding environments of elements in minerals and other materials.

Reference: Koningsberger, D. C., & Prins, R. (1988). “X-ray Absorption: Principles, Applications, Techniques of EXAFS, SEXAFS, and XANES.” Wiley.

^XX-ray Crystallography

X-ray crystallography is a technique used to determine the atomic and molecular structure of a crystal by measuring the diffraction patterns of X-rays passing through it. This method is significant in mineralogy and chemistry for understanding the detailed structure of minerals, the arrangement of atoms within a crystal, and the properties of materials.

Reference: Girolami, G. S. (1994). “X-ray Crystallography.” University Science Books.

^XX-ray Diffraction (XRD)

X-ray diffraction (XRD) is a technique used to determine the crystallographic structure of minerals and other crystalline materials by measuring the angles and intensities of diffracted X-rays. XRD is significant in mineralogy and materials science for identifying minerals, analyzing crystal structures, and studying phase transitions in materials.

Reference: Cullity, B. D., & Stock, S. R. (2001). “Elements of X-ray Diffraction.” Prentice Hall.

^XX-ray Spectroscopy

X-ray spectroscopy is a technique used to analyze the composition and electronic structure of materials by measuring the characteristic X-rays emitted by elements when they are excited by an X-ray source. This method is significant in geochemistry and material science for identifying elements, studying chemical bonding, and understanding the properties of minerals and rocks.

Reference: Jenkins, R. (1999). “X-ray Fluorescence Spectrometry.” Wiley-Interscience.

^XXenocryst

A xenocryst is a crystal that is not formed from the magma in which it is found but has been incorporated into the magma from surrounding rocks. Xenocrysts are significant in petrology for understanding magma contamination, the processes of magma assimilation, and the interactions between different rock types during magmatic activity.

Reference: Smith, D. (1992). “Xenocrysts in Kimberlites and Other Volcanic Rocks.” Journal of Volcanology and Geothermal Research, 50(1-2), 83-98.

^XXenogenic

Xenogenic refers to something that originates outside the host rock or organism, often used to describe minerals, crystals, or rock fragments that have been introduced into a host rock from an external source. This concept is significant in petrology and mineralogy for understanding the processes of rock formation, contamination, and the history of geological materials.

Reference: Nesse, W. D. (2012). “Introduction to Mineralogy.” Oxford University Press.

^XXenolith

A xenolith is a fragment of rock that is enclosed within a larger body of igneous rock, typically carried to the surface by volcanic eruptions. Xenoliths are significant in petrology for providing information about the composition and conditions of the Earth’s mantle and lower crust, offering insights into deep geological processes.

Reference: Gillet, P., McMillan, P., & Guyot, F. (1992). “Thermodynamic Properties and Geophysical Applications of Xenoliths.” Nature, 357(6374), 164-168.

^YYakutat Block

The Yakutat Block is a fragment of oceanic crust and overlying sedimentary rocks that has been accreted onto the southern margin of Alaska. This block is significant in tectonics and seismology for its role in the active deformation and seismicity of southern Alaska, the uplift of the St. Elias Mountains, and the ongoing collision between the Pacific Plate and North America.

Reference: Plafker, G., & Berg, H. C. (1994). “The Geology of Alaska.” Geological Society of America.

^YYali Caldera

The Yali Caldera is a volcanic caldera located in the Aegean Sea, Greece, formed by a series of explosive eruptions during the Quaternary period. The caldera is significant in volcanology and geothermal studies for its active geothermal fields, its potential for future volcanic activity, and its role in shaping the geology of the region.

Reference: Fytikas, M., & Innocenti, F. (1998). “The South Aegean Active Volcanic Arc: Present Knowledge and Future Perspectives.” Memorie della Società Geologica Italiana, 53, 69-80.

^MArchives: Glossary

Metasomatic alteration refers to the process by which a rock’s mineral composition is altered due to the introduction of new chemical components through fluid interactions. This alteration can lead to the formation of economically important mineral deposits and is key to understanding hydrothermal systems.

Reference: Dale, J. (2011). “Fluid-Rock Interactions during Metasomatism.” Elements, 7(5), 315-320.