Glossary

Borax

Fact Sheet:

Chemical Composition: Na₂[B₄O₅(OH)₄]·8H₂O (Sodium Borate Decahydrate)
Hardness: 2 to 2.5 on the Mohs scale
Crystal System: Monoclinic
Color Varieties: Colorless to white, sometimes with gray, yellow, green, or brown tints due to impurities
Major Localities: United States (California), Turkey, Chile, and Tibet
Common Uses: Cleaning agent, glassmaking, ceramics, metallurgy, and as an insecticide

Introduction: Borax is a versatile mineral widely known for its use in household cleaning products, but its industrial and scientific importance goes far beyond that. A naturally occurring compound of boron, sodium, and water, borax plays a crucial role in glassmaking, agriculture, ...

^TTravertine

Travertine is a form of limestone deposited by mineral springs, especially hot springs. This sedimentary rock is significant in geology for understanding the processes of carbonate precipitation, hydrothermal activity, and the formation of cave and spring deposits.

Reference: Pentecost, A. (2005). “Travertine.” Springer.

^TTrench

An oceanic trench is a deep, linear depression in the ocean floor formed by the subduction of one tectonic plate beneath another. Trenches are significant in geology for understanding subduction zones, plate tectonics, and the processes that lead to volcanic arcs and earthquake activity.

Reference: Hilde, T. W. C., Uyeda, S., & Kroenke, L. W. (1977). “Evolution of the Western Pacific and Its Margin.” Tectonophysics, 38(1-2), 145-165.

^TTrilobite

Trilobites are an extinct group of marine arthropods that lived during the Paleozoic Era, known for their distinctive three-lobed, three-segmented body plan. They are significant in paleontology for understanding the evolution of early life, the diversity of ancient marine ecosystems, and the use of fossils in biostratigraphy.

Reference: Fortey, R. A. (2000). “Trilobite! Eyewitness to Evolution.” Vintage Books.

^TTroposphere

The troposphere is the lowest layer of Earth’s atmosphere, extending from the surface to an altitude of about 8-15 kilometers. It is significant in meteorology and climatology for understanding weather patterns, climate dynamics, and the interactions between the Earth’s surface and the atmosphere.

Reference: Wallace, J. M., & Hobbs, P. V. (2006). “Atmospheric Science: An Introductory Survey.” Academic Press.

^TTsunami

A tsunami is a series of ocean waves with extremely long wavelengths and periods, typically caused by large underwater earthquakes, volcanic eruptions, or landslides. Tsunamis are significant for understanding coastal hazards, oceanography, and the impact of natural disasters on coastal communities.

Reference: Bryant, E. (2001). “Tsunami: The Underrated Hazard.” Cambridge University Press.

^TTsunamiite

Tsunamiite is a sedimentary deposit formed by a tsunami, typically characterized by a distinct layer of mixed sediments that may include marine fossils, rip-up clasts, and coarse debris. Tsunamiites are significant in sedimentology for understanding past tsunami events, their sedimentary signatures, and the impacts on coastal environments.

Reference: Goto, K., Chague-Goff, C., & Jaffe, B. E. (2012). “The Future of Tsunami Research Following the 2011 Tohoku-Oki Event.” Sedimentary Geology, 282, 1-13.

^TTuff

Tuff is a type of rock made of volcanic ash ejected from a vent during an eruption, which has then consolidated into a solid mass. Tuff is important in volcanology for understanding explosive volcanic eruptions and the deposition of pyroclastic materials.

Reference: Fisher, R. V., & Schmincke, H.-U. (1984). “Pyroclastic Rocks.” Springer.

^TTuff Cone

A tuff cone is a steep, cone-shaped volcanic landform built from the accumulation of volcanic ash and tephra ejected during a phreatomagmatic eruption, where magma interacts with water. Tuff cones are significant in volcanology for understanding the dynamics of explosive eruptions and the formation of volcanic landforms.

Reference: Heiken, G., & Wohletz, K. (1985). “Volcanic Ash.” University of California Press.

^TTuff Ring

A tuff ring is a low, wide volcanic crater formed by the explosive interaction of magma with water, producing a ring of tuff (consolidated volcanic ash) around the vent. Tuff rings are significant in volcanology for understanding phreatomagmatic eruptions and the formation of volcanic landforms.

Reference: Lorenz, V. (1986). “On the Growth of Maars and Diatremes and Its Relevance to the Formation of Tuff Rings.” Bulletin of Volcanology, 48(5), 265-274.

^TTurbidite

A turbidite is a sedimentary deposit formed by turbidity currents, which are underwater flows of sediment-laden water that move down continental slopes and deposit layers of sediment. Turbidites are significant in sedimentology for interpreting deep-sea depositional environments and the history of submarine sedimentation.

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

^UU-Channel Sampling

U-channel sampling is a technique used in paleomagnetism and sedimentology to extract continuous samples of sediments or rock cores in the shape of a “U,” allowing for detailed magnetic and geochemical analysis. This method is significant for reconstructing past environmental conditions, magnetic field variations, and sedimentary processes.

Reference: Tauxe, L. (2010). “Essentials of Paleomagnetism.” University of California Press.

^UU-Shaped Valley

A U-shaped valley is a valley with a characteristic U-shaped cross-section, formed by glacial erosion. These valleys are significant in geomorphology for understanding glacial processes, the history of glaciation, and the sculpting of mountain landscapes.

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

^UUbiquitous Clay

Ubiquitous clay refers to the widespread presence of clay minerals in various geological environments, including soils, sedimentary rocks, and hydrothermal deposits. These clays are significant in sedimentology, soil science, and economic geology for their role in soil formation, sedimentary processes, and the development of clay-rich mineral deposits.

Reference: Moore, D. M., & Reynolds, R. C. (1997). “X-ray Diffraction and the Identification and Analysis of Clay Minerals.” Oxford University Press.

^UUltracataclasite

Ultracataclasite is a type of fault rock formed by intense mechanical grinding and crushing of rocks along a fault zone, resulting in a very fine-grained, cohesive rock. This material is significant in structural geology for understanding fault mechanics, earthquake processes, and the evolution of fault zones.

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

^UUltraconglomerate

Ultraconglomerate is a coarse-grained sedimentary rock composed of very large clasts, often exceeding several meters in size, cemented together. This rock type is significant in sedimentology for understanding high-energy depositional environments, such as alluvial fans and glacial deposits, and the processes of sediment transport and deposition.

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

^UUltrahigh-Pressure Metamorphism

Ultrahigh-pressure (UHP) metamorphism occurs when rocks are subjected to pressures greater than 2.5 GPa, often during continental collision. UHP metamorphic rocks, such as coesite-bearing eclogite, are significant in geology for providing evidence of deep subduction and the dynamics of crustal processes.

Reference: Chopin, C. (2003). “Ultrahigh-Pressure Metamorphism: Tracing Continental Crust into the Mantle.” Earth and Planetary Science Letters, 212(1-2), 1-14.

^UUltrahigh-Temperature Metamorphism

Ultrahigh-temperature (UHT) metamorphism occurs at extreme temperatures exceeding 900°C, often associated with tectonic plate collisions or deep burial of crustal rocks. UHT metamorphic rocks are significant in petrology for understanding the conditions of deep crustal metamorphism, the evolution of orogenic belts, and the processes of crustal melting.

Reference: Harley, S. L. (1998). “Ultrahigh-Temperature Metamorphism: A New Window on the Thermal Evolution of the Continental Crust.” Geology, 26(4), 315-318.

^UUltramafic Rock

Ultramafic rocks are igneous rocks with very low silica content and high levels of magnesium and iron. These rocks, which include peridotite and dunite, are significant in petrology for understanding the composition of the Earth’s mantle and the processes of mantle melting and magma formation.

Reference: Le Maitre, R. W. (2002). “Igneous Rocks: A Classification and Glossary of Terms.” Cambridge University Press.

^UUltrasonic Attenuation

Ultrasonic attenuation refers to the decrease in amplitude of ultrasonic waves as they propagate through a material, often used to characterize the material’s properties. This concept is significant in geophysics for subsurface imaging, detecting fractures, and understanding the mechanical properties of rocks.

Reference: Krautkrämer, J., & Krautkrämer, H. (1990). “Ultrasonic Testing of Materials.” Springer.

^UUltrasonic Velocity

Ultrasonic velocity refers to the speed at which ultrasonic waves travel through a material, commonly used in geophysical surveys to characterize rock properties. Ultrasonic velocity is significant in geophysics for understanding the elastic properties of rocks, subsurface imaging, and the detection of fractures and faults.

Reference: Krautkrämer, J., & Krautkrämer, H. (1990). “Ultrasonic Testing of Materials.” Springer.

^UUnconfined Aquifer

An unconfined aquifer is a groundwater reservoir that is directly open to the atmosphere through porous material, such as soil or permeable rock, allowing for the free movement of water. Unconfined aquifers are significant in hydrogeology for understanding groundwater recharge, water table dynamics, and the availability of water resources.

Reference: Freeze, R. A., & Cherry, J. A. (1979). “Groundwater.” Prentice Hall.

^UUnconformity

An unconformity is a surface within a sequence of layers of sedimentary rock where rock deposition ceased, and erosion removed some previously formed layers before deposition resumed. Unconformities are significant in stratigraphy for understanding geological time gaps, the history of sedimentary basins, and tectonic events.

Reference: Miall, A. D. (1997). “The Geology of Stratigraphic Sequences.” Springer.

^UUnconsolidated Material

Unconsolidated material refers to loose, uncemented geological deposits such as soil, sand, gravel, and silt that have not been lithified into solid rock. These materials are significant in sedimentology, soil science, and engineering for understanding sediment transport, soil properties, and the stability of foundations and slopes.

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

^PArchives: Glossary

A paleosol is a fossil soil, preserved in the geological record, that formed on a landscape surface in the past. Paleosols are important for reconstructing past climates, vegetation, and landscapes, as well as for understanding soil development and diagenetic processes over geological time scales.

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