Glossary

Apatite

Fact Sheet:

Chemical Composition: Ca₅(PO₄)₃(F, Cl, OH) (Calcium Phosphate)
Hardness: 5 on the Mohs scale
Crystal System: Hexagonal
Color Varieties: Green, blue, yellow, purple, brown, pink, and colorless
Major Localities: Canada, Brazil, Russia, Mexico, and the United States
Common Uses: Source of phosphate for fertilizer, gemstones, and industrial applications

Introduction: Apatite is a widely occurring mineral, essential for both biological processes and industrial applications. Its name is derived from the Greek word “apate,” meaning “deceit,” due to its similarity to other minerals, which led to confusion in its early identification. Apatite is the primary source of phosphorus, ...

^TTephrostratigraphy

Tephrostratigraphy is the study of volcanic ash layers (tephra) within the stratigraphic record, used to correlate and date sedimentary sequences. This method is significant in geology and archaeology for constructing precise chronological frameworks, correlating events across regions, and studying volcanic activity.

Reference: Lowe, D. J. (2011). “Tephrochronology and Its Application: A Review.” Quaternary Geochronology, 6(2), 107-153.

^TTerrane

A terrane is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or sutured onto the crust lying on another plate. Terranes are significant in geology for understanding the growth and evolution of continental crust, as well as the processes of tectonic accretion.

Reference: Howell, D. G. (1995). “Principles of Terrane Analysis: New Applications for Global Tectonics.” Elsevier.

^TTerrigenous Sediment

Terrigenous sediment is sediment derived from the erosion of continental rocks, transported to the ocean by rivers, wind, or glaciers. This type of sediment is significant in sedimentology for understanding the sources and transport mechanisms of sedimentary materials, as well as the processes of sedimentation in marine environments.

Reference: Pettijohn, F. J., Potter, P. E., & Siever, R. (1987). “Sand and Sandstone.” Springer.

^TThalweg

The thalweg is the line of lowest elevation within a river or stream channel, often representing the path of fastest flow. It is significant in fluvial geomorphology for understanding river dynamics, channel formation, and the management of waterways.

Reference: Leopold, L. B., Wolman, M. G., & Miller, J. P. (1964). “Fluvial Processes in Geomorphology.” Dover Publications.

^TThermal Metamorphism

Thermal metamorphism, also known as contact metamorphism, occurs when rocks are heated by the intrusion of hot magma without significant deformation. This process is significant in petrology for understanding the effects of heat on mineral stability, the formation of metamorphic rocks, and the thermal history of magmatic intrusions.

Reference: Philpotts, A. R., & Ague, J. J. (2009). “Principles of Igneous and Metamorphic Petrology.” Cambridge University Press.

^TThermokarst

Thermokarst refers to the land surface that forms as ice-rich permafrost thaws and collapses, creating features like sinkholes, ponds, and uneven terrain. This process is significant in periglacial geomorphology for understanding the impacts of climate change on permafrost regions and the associated risks of land subsidence.

Reference: French, H. M. (2007). “The Periglacial Environment.” John Wiley & Sons.

^TTholeiitic Basalt

Tholeiitic basalt is a type of basaltic rock characterized by low alkali content and high iron content, commonly found at mid-ocean ridges and volcanic islands. This rock type is significant for understanding magma differentiation, mid-ocean ridge processes, and the geochemistry of basaltic magmas.

Reference: Carmichael, I. S. E. (1964). “The Petrology of Thingmuli, a Tertiary Volcano in Eastern Iceland.” Journal of Petrology, 5(3), 435-460.

^TTholeiitic Series

The tholeiitic series is a sequence of igneous rocks that range from basalt to rhyolite, characterized by low potassium content and a specific pattern of mineral crystallization. This series is significant in petrology for understanding the evolution of basaltic magmas, mid-ocean ridge processes, and the geochemistry of volcanic arcs.

Reference: Winter, J. D. (2010). “Principles of Igneous and Metamorphic Petrology.” Pearson.

^TThrust Belt

A thrust belt is a region of the Earth’s crust where compressional tectonic forces have created a series of thrust faults, leading to the stacking of crustal blocks and the formation of mountain ranges. Thrust belts are significant in structural geology for understanding mountain-building processes and the mechanics of crustal deformation.

Reference: Suppe, J. (1985). “Principles of Structural Geology.” Prentice Hall.

^TThrust Fault

A thrust fault is a type of reverse fault where the angle of the fault plane is shallow, causing the hanging wall to move up relative to the footwall. Thrust faults are significant in structural geology for understanding compressional forces that lead to the shortening of the Earth’s crust, often associated with mountain building.

Reference: Boyer, S. E., & Elliott, D. (1982). “Thrust Systems.” American Association of Petroleum Geologists Bulletin, 66(9), 1196-1230.

^TThrust Nappe

A thrust nappe is a large sheet of rock that has been displaced horizontally over a considerable distance along a thrust fault, often forming part of a mountain range. Thrust nappes are significant in structural geology for understanding the mechanics of large-scale crustal deformation and the formation of orogenic belts.

Reference: Price, N. J., & Cosgrove, J. W. (1990). “Analysis of Geological Structures.” Cambridge University Press.

^TTidal Bore

A tidal bore is a strong surge of water that travels upstream against the current in a river or estuary during a rising tide. Tidal bores are significant in hydrology for understanding the dynamics of tidal waves, riverine processes, and the impact of tides on estuarine ecosystems.

Reference: Chanson, H. (2011). “Tidal Bores, Aegir, Eagre, Mascaret, Pororoca: Theory and Observations.” World Scientific.

^TTidal Flat

A tidal flat is a flat, often muddy area that is exposed at low tide and submerged at high tide, typically found in coastal regions. Tidal flats are significant in sedimentology for understanding the deposition of fine-grained sediments, the dynamics of coastal environments, and the development of ecosystems adapted to fluctuating water levels.

Reference: Ginsburg, R. N. (1953). “Intertidal Sedimentation in the Colorado River Delta.” Journal of Sedimentary Petrology, 23(4), 182-198.

^TTidal Range

Tidal range is the vertical difference between the high tide and the low tide, which can vary significantly depending on the location and the phase of the moon. Tidal range is significant in oceanography and coastal geology for understanding the dynamics of tides, the formation of tidal currents, and the impact of tides on coastal environments.

Reference: Pugh, D. T. (1987). “Tides, Surges and Mean Sea-Level: A Handbook for Engineers and Scientists.” Wiley.

^TTombolo

A tombolo is a coastal landform where an island is connected to the mainland or another island by a narrow strip of sand or gravel, formed by the deposition of sediments in the wave shadow of the island. Tombolos are significant in coastal geomorphology for understanding sediment transport, wave dynamics, and the formation of coastal features.

Reference: Masselink, G., & Hughes, M. G. (2003). “Introduction to Coastal Processes and Geomorphology.” Hodder Arnold.

^TTopography

Topography refers to the arrangement of natural and artificial features on the Earth’s surface, including the study of relief, elevation, and landforms. It is significant in geography, geology, and environmental science for understanding landscape evolution, land use planning, and the interaction between natural processes and human activities.

Reference: Strahler, A. H. (1969). “Physical Geography.” Wiley.

^TTopset Bed

Topset beds are horizontal layers of sediment deposited on top of a delta, often representing the most recent phase of deltaic deposition. These beds are significant in sedimentology for understanding the dynamics of delta formation, sediment transport, and the stratigraphic record of deltaic environments.

Reference: Reading, H. G., & Collinson, J. D. (1996). “Clastic Coasts.” Sedimentary Environments: Processes, Facies and Stratigraphy, 154-231.

^TTrace Fossil

A trace fossil, also known as an ichnofossil, is a geological record of biological activity, such as footprints, burrows, or feeding marks, rather than the remains of the organism itself. Trace fossils are significant in paleontology for understanding the behavior of ancient organisms, their interactions with the environment, and the interpretation of sedimentary environments.

Reference: Bromley, R. G. (1996). “Trace Fossils: Biology, Taphonomy, and Applications.” Chapman & Hall.

^TTrachyte

Trachyte is a fine-grained, alkali-rich volcanic rock composed predominantly of alkali feldspar, with lesser amounts of mafic minerals. It is significant in petrology for understanding the evolution of alkaline magmas, the processes of magmatic differentiation, and the geochemistry of volcanic rocks.

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

^TTranscurrent Fault

A transcurrent fault is a type of strike-slip fault where the motion is predominantly horizontal, with little vertical displacement. These faults are significant in tectonics for understanding lateral movements of the Earth’s crust, the formation of fault zones, and the seismic activity associated with these faults.

Reference: Sylvester, A. G. (1988). “Strike-Slip Faults.” Geological Society of America Bulletin, 100(11), 1666-1703.

^TTransform Boundary

A transform boundary is a type of plate boundary where two tectonic plates slide past each other horizontally. Transform boundaries are significant in plate tectonics for understanding the movement and interaction of tectonic plates, as well as the formation of earthquakes along these boundaries.

Reference: Gordon, R. G., & Stein, S. (1992). “Global Tectonics and the Wilson Cycle.” Geological Society of America Bulletin, 104(8), 1073-1083.

^TTransform Fault

A transform fault is a type of strike-slip fault that occurs at the boundary between two tectonic plates sliding past each other. Transform faults are significant in plate tectonics for accommodating horizontal displacement between plates, commonly found along mid-ocean ridges.

Reference: Scholz, C. H. (1990). “The Mechanics of Earthquakes and Faulting.” Cambridge University Press.

^TTransgression

A transgression is a geological event during which sea level rises relative to the land, causing the shoreline to move inland. This process is significant in sedimentology for understanding the deposition of marine sediments, the formation of transgressive sequences, and the changes in coastal environments over time.

Reference: Catuneanu, O. (2006). “Principles of Sequence Stratigraphy.” Elsevier.

^QArchives: Glossary

The quasi-geoid is a reference surface similar to the geoid but used in some geodetic calculations. It approximates the Earth’s mean sea level and is significant for precise geodetic measurements, mapping, and understanding the Earth’s gravitational field.

Reference: Hofmann-Wellenhof, B., & Moritz, H. (2006). “Physical Geodesy.” Springer.