Glossary

Halite

Fact Sheet:
– Chemical Composition: NaCl (Sodium Chloride)
– Hardness: 2 to 2.5 on the Mohs scale
– Crystal System: Isometric
– Color Varieties: Colorless, white, blue, purple, pink, red, orange, yellow
– Major Localities: United States, China, Germany, Canada, and Poland
– Common Uses: Food seasoning, de-icing roads, chemical feedstock, water conditioning, and industrial applications

Introduction: Halite, commonly known as rock salt, is a mineral form of sodium chloride. It has been an essential resource for humans for thousands of years, used in everything from food preservation to modern industrial processes. The name “halite” is derived from the Greek ...

^BBasaltic Plateau

A basaltic plateau is a large, flat region of extensive basaltic lava flows, often resulting from multiple, successive eruptions that cover large areas with basalt. These plateaus are significant in the study of volcanic activity and the geological history of regions, often linked to hotspot volcanism or rifting events.

Reference: Bryan, S. E., & Ernst, R. E. (2008). “Large Igneous Provinces and the Mantle Plume Hypothesis.” Elements, 4(1), 31-35.

^BBasin and Range Province

The Basin and Range Province is a vast region in the western United States characterized by alternating narrow mountain ranges and flat, arid valleys (basins). This distinctive topography is a result of crustal extension that has stretched and thinned the Earth’s crust, causing faulting and block faulting. The study of this province provides valuable insights into extensional tectonics and the processes that shape continental rifts.

Reference: Wernicke, B. (1992). “Cenozoic Extensional Tectonics of the U.S. Cordillera.” In: The Cordilleran Orogen: Conterminous U.S. Geological Society of America.

^BBatholith

A batholith is a large mass of intrusive igneous rock, typically granite, that has crystallized from magma deep within the Earth’s crust. Batholiths are usually exposed at the surface after extensive erosion removes the overlying material. They are significant geological features that can cover hundreds of square kilometers and are often associated with mountain ranges.

Reference: Pitcher, W. S. (1997). The Nature and Origin of Granite. Chapman & Hall.

^BBathymetry

Bathymetry is the study and mapping of the seafloor’s topography, including its depth and underwater features. It is crucial for understanding oceanographic processes, submarine geology, and the habitats of marine organisms. Modern bathymetric mapping is conducted using sonar and satellite altimetry, providing detailed images of the ocean floor.

Reference: Wright, J. D., & Rothwell, R. G. (2000). “Bathymetry: The Foundation of Oceanography.” In: Oceanography: An Invitation to Marine Science.

^BBeach Ridge

A beach ridge is a low, elongated ridge that forms parallel to the shoreline, often composed of sand, gravel, or shell material. These ridges are created by the action of waves and currents and can indicate former positions of the shoreline. Beach ridges are significant in coastal geology for reconstructing past sea levels, storm events, and changes in coastal dynamics.

Reference: Hesp, P. A. (2006). “Beach Ridges: Definitions and Genesis.” Journal of Coastal Research, 22(4), 613-622.

^BBed Load

Bed load refers to the sediment particles that are transported along the bottom of a river or stream by rolling, sliding, or hopping. This process occurs in rivers with sufficient flow velocity to move larger particles, such as sand, gravel, and cobbles. Bed load transport is a critical aspect of fluvial geomorphology, influencing channel shape, sediment deposition, and river dynamics.

Reference: Bagnold, R. A. (1966). “An Approach to the Sediment Transport Problem from General Physics.” Geological Survey Professional Paper 422-I. U.S. Geological Survey.

^BBeheaded Stream

A beheaded stream is a stream or river that has been diverted or cut off from its original source due to geological processes such as faulting, volcanic activity, or glaciation. This can result in a dry riverbed or a stream with reduced flow. Beheaded streams provide evidence of past geological events and are studied to understand landscape evolution and the effects of tectonic activity.

Reference: Summerfield, M. A. (1991). Global Geomorphology. Longman Scientific & Technical.

^BBenioff Zone

The Benioff zone is a zone of seismic activity that occurs along the subducting slab of an oceanic plate as it descends into the mantle beneath an overriding plate. This zone is characterized by a dipping plane of earthquakes, which can extend from near the surface to depths of 700 kilometers. The study of Benioff zones provides critical insights into the mechanics of subduction and the forces driving plate tectonics.

Reference: Isacks, B., Oliver, J., & Sykes, L. R. (1968). “Seismology and the New Global Tectonics.” Journal of Geophysical Research, 73(18), 5855-5899.

^BBiogenic Sediments

Biogenic sediments are formed from the accumulation of organic material, such as the remains of plants, animals, and microorganisms. Common types include limestone, formed from marine organisms’ shells and skeletons, and coal, derived from compressed plant material. These sediments are crucial for understanding past environmental conditions, the carbon cycle, and the formation of fossil fuels.

Reference: Hedges, J. I., & Keil, R. G. (1995). “Sedimentary Organic Matter Preservation: An Assessment and Speculative Synthesis.” Marine Chemistry, 49(2-3), 81-115.

^BBiostratigraphy

Biostratigraphy is a branch of stratigraphy that uses the fossil content of rock layers to establish relative ages and correlate strata across different geographic regions. Fossils, particularly those of species that were widespread but only existed for a short geological period (index fossils), are crucial for identifying and dating rock units. Biostratigraphy is essential in paleontology, geology, and petroleum exploration.

Reference: Gradstein, F. M., Ogg, J. G., Schmitz, M. D., & Ogg, G. M. (2012). The Geologic Time Scale 2012. Elsevier.

^BBioturbation

Bioturbation refers to the reworking of soils and sediments by living organisms, such as burrowing animals, worms, and roots. This process alters the texture, structure, and composition of sediments, playing a vital role in the formation of soil profiles and the cycling of nutrients. Bioturbation is an essential concept in sedimentology, paleontology, and soil science.

Reference: Kristensen, E., & Kostka, J. E. (2005). “Macrofaunal Burrows and Irrigation in Marine Sediment: Microbiological and Biogeochemical Interactions.” In: Interactions Between Macro- and Microorganisms in Marine Sediments, American Geophysical Union.

^BBivalve

Bivalves are a class of marine and freshwater mollusks that have bodies enclosed by a hinged shell consisting of two parts. Fossilized bivalves are significant in paleontology and biostratigraphy, providing insights into ancient marine environments and helping to date sedimentary rock layers. Bivalves are also key indicators of water quality and environmental change.

Reference: Stanley, S. M. (1970). “Relation of Shell Form to Life Habits of the Bivalvia (Mollusca).” The Geological Society of America Memoir 125.

^BBlack Smoker

Black smokers are hydrothermal vent structures on the ocean floor that emit superheated water rich in dissolved minerals, primarily sulfides, which precipitate upon contact with cold seawater, forming chimney-like structures. These vents are found along mid-ocean ridges and are significant in studying seafloor spreading, mineral deposits, and the unique ecosystems that thrive in these extreme environments.

Reference: Van Dover, C. L. (2000). The Ecology of Deep-Sea Hydrothermal Vents. Princeton University Press.

^BBlock Faulting

Block faulting is a geological process where the Earth’s crust is broken into large, fault-bounded blocks that are displaced vertically relative to one another. This process is commonly associated with extensional tectonics, where the crust is being pulled apart, such as in the Basin and Range Province of the western United States. Block faulting plays a significant role in the formation of rift valleys and mountain ranges.

Reference: Wernicke, B. (1981). “Low-Angle Normal Faults in the Basin and Range Province: Nappe Tectonics in an Extending Orogen.” Nature, 291(5810), 645-648.

^BBlow Sand

Blow sand refers to loose, wind-blown sand that accumulates in deserts or along coastlines, forming dunes or other aeolian landforms. Blow sand is significant in the study of desertification, dune dynamics, and the effects of wind on sediment transport. It also plays a role in shaping the landscapes of arid regions.

Reference: Cooke, R. U., Warren, A., & Goudie, A. (1993). Desert Geomorphology. UCL Press.

^BBlowhole

A blowhole is a geological feature formed in coastal cliffs, where a sea cave extends upwards to the surface, creating a hole through which air and water are expelled during high tides or stormy weather. Blowholes are indicators of coastal erosion processes and are significant in the study of marine geomorphology and coastal dynamics.

Reference: Stephenson, W. J., & Naylor, L. A. (2011). “Geological Controls on Benthic Habitats in Coastal Caves and Blowholes.” Geo-Marine Letters, 31(3), 181-191.

^BBlowout

A blowout is a depression in a sand dune or other sandy area caused by wind erosion. Blowouts occur when vegetation cover is disturbed or removed, allowing the wind to erode the underlying sand. These features are common in coastal and desert environments and can indicate changes in wind patterns, climate, or land use.

Reference: Carter, R. W. G., & Woodroffe, C. D. (1994). Coastal Evolution: Late Quaternary Shoreline Morphodynamics. Cambridge University Press.

^BBlueschist

Blueschist is a type of metamorphic rock that forms under high-pressure, low-temperature conditions typically found in subduction zones. It is characterized by the presence of blue-colored amphibole minerals such as glaucophane. Blueschist facies rocks are important in the study of tectonics and metamorphism, providing insights into the conditions and processes in subduction environments.

Reference: Ernst, W. G. (1973). “Blueschist Metamorphism and P-T Paths in Subduction Zones.” American Journal of Science, 273(6), 577-606.

^BBluff

A bluff is a steep, high bank or cliff, typically formed by erosion along rivers, coastlines, or other areas where water and wind action can remove softer materials, leaving behind harder, more resistant rock. Bluffs are significant in the study of erosion, sediment transport, and the formation of landforms, providing insights into the processes shaping the landscape.

Reference: Thornbury, W. D. (1954). Principles of Geomorphology. Wiley.

^BBoreal Forest

The boreal forest, also known as taiga, is a biome characterized by coniferous forests consisting mostly of pines, spruces, and larches. It is found in the northern regions of North America, Europe, and Asia, just below the Arctic Circle. This forest type plays a crucial role in the global carbon cycle, acting as a significant carbon sink. Boreal forests are vital for understanding climate change impacts and are subject to environmental threats like logging, mining, and climate-induced shifts in species distribution.

Reference: Bonan, G. B., & Shugart, H. H. (1989). “Environmental Factors and Ecological Processes in Boreal Forests.” Annual Review of Ecology and Systematics, 20(1), 1-28.

^BBorehole

A borehole is a narrow, deep hole drilled into the ground for the purpose of extracting water, oil, gas, or minerals, or for scientific investigation. Boreholes are critical in hydrogeology for accessing groundwater and in the oil and gas industry for exploration and production. They also provide valuable data on subsurface geology, including rock strata, porosity, and fluid content.

Reference: Driscoll, F. G. (1986). Groundwater and Wells. Johnson Filtration Systems Inc.

^BBoudinage

Boudinage refers to a structure formed when a layer of rock is stretched and deformed into segments resembling a string of sausages, known as “boudins.” This occurs during ductile deformation under tension, typically in layered rocks. Boudinage provides insights into the stress and strain conditions during tectonic deformation and is often studied in the context of structural geology.

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

^BBoulder Clay

Boulder clay, also known as till, is a type of unsorted glacial sediment composed of clay, sand, gravel, and boulders that were deposited directly by a glacier. It is significant in the study of glacial processes and the reconstruction of past glacial environments. Boulder clay often serves as a key indicator of glaciation in the geological record.

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

^YArchives: Glossary

The Yukon-Tanana Terrane is a geologic terrane in the Canadian Yukon and eastern Alaska, consisting of metamorphic and igneous rocks that have been accreted onto the North American continent. This terrane is significant in tectonics and regional geology for understanding the processes of terrane accretion, the tectonic history of the Cordilleran orogen, and the mineral resources in the region.

Reference: Mortensen, J. K. (1992). “Pre-Mid-Mesozoic Tectonic Evolution of the Yukon-Tanana Terrane, Yukon and Alaska.” Tectonics, 11(4), 836-853.