Glossary

Pyroxene

Fact Sheet:

Chemical Composition: General formula XY(Si, Al)₂O₆, where X can be calcium (Ca), sodium (Na), iron (Fe²⁺), or magnesium (Mg), and Y is typically magnesium (Mg), iron (Fe), or aluminum (Al)
Hardness: 5 to 7 on the Mohs scale
Crystal System: Monoclinic or orthorhombic
Color Varieties: Green, black, brown, white, yellow, and dark gray
Major Localities: United States, Italy, Norway, Australia, Canada, and Japan
Common Uses: Rock-forming mineral in igneous and metamorphic rocks, ceramics, and geological research

Introduction: Pyroxene is a group of important rock-forming minerals found in many igneous and metamorphic rocks. Characterized by their ...

^FFrost Heaving

Frost heaving is the upward movement of soil or rock caused by the freezing and expansion of water in the ground. This process is significant in cold climates and can cause damage to roads, buildings, and other structures. Understanding frost heaving is important in geotechnical engineering, soil mechanics, and the study of periglacial environments.

Reference: Andersland, O. B., & Ladanyi, B. (2004). Frozen Ground Engineering. John Wiley & Sons.

^FFrost Wedging

Frost wedging is a type of physical weathering that occurs when water enters cracks in rocks, freezes, and expands, causing the rock to break apart. This process is common in cold climates and contributes to the breakdown of rocks into smaller fragments. Frost wedging is significant in the study of weathering processes, landscape evolution, and soil formation.

Reference: Hall, K. (1986). The Role of Thermal Stress in the Breakdown of Rock in Cold Regions. Geological Society of America Bulletin.

^FFumarole

A fumarole is an opening in the Earth’s crust, often near volcanoes, that emits steam and gases such as carbon dioxide, sulfur dioxide, and hydrogen sulfide. Fumaroles are significant in volcanology for studying the degassing processes of magma, the chemical composition of volcanic gases, and the potential hazards associated with volcanic activity.

Reference: Symonds, R. B., Rose, W. I., Bluth, G. J. S., & Gerlach, T. M. (1994). Volcanic-Gas Studies: Methods, Results, and Applications. In: Carroll, M. R., & Holloway, J. R. (Eds.), Volatiles in Magmas. Reviews in Mineralogy.

^GGeochronology

Geochronology is the science of determining the age of rocks, fossils, and sediments through the use of dating methods such as radiometric dating. This field is crucial for understanding the timing of geological events, the history of the Earth, and the age of different rock formations.
Reference: Faure, G., & Mensing, T. M. (2005). Isotopes: Principles and Applications. Wiley.

^GGeodynamo

The geodynamo is the mechanism by which the Earth’s magnetic field is generated through the motion of conductive materials in the Earth’s outer core. The geodynamo is crucial in understanding geomagnetism, the behavior of the Earth’s magnetic field over geological time, and its implications for plate tectonics and life on Earth.
Reference: Glatzmaier, G. A., & Roberts, P. H. (1995). A Three-Dimensional Self-Consistent Computer Simulation of a Geodynamo. Nature.

^GGeomorphology

Geomorphology is the scientific study of landforms and the processes that shape them. This field covers a wide range of topics, including the study of rivers, mountains, glaciers, deserts, and coastal regions. Geomorphology is crucial for understanding Earth’s surface processes, landscape evolution, and the interaction between climate, tectonics, and erosion.
Reference: Summerfield, M. A. (1991). Global Geomorphology: An Introduction to the Study of Landforms. Routledge.

^GGeopetal Structure

Geopetal structures are sedimentary features that indicate the original “way up” of the rock at the time of deposition. These structures, such as graded bedding or fossils, are used to determine the orientation of rock layers in deformed or tilted sequences, making them important in structural geology and stratigraphy.
Reference: Selley, R. C. (2000). Applied Sedimentology. Academic Press.

^GGeospeedometry

Geospeedometry is a technique used to estimate the cooling rates of rocks and minerals by analyzing the diffusion profiles of specific elements within the minerals. This method is important in understanding the thermal history of igneous and metamorphic rocks, the rates of geological processes, and the conditions of rock formation.
Reference: Lasaga, A. C. (1983). Geospeedometry: An Introduction to the Quantitative Measurement of Time in Petrology. Journal of Petrology.

^GGeostrophic Flow

Geostrophic flow is a type of fluid flow in which the Coriolis force due to the Earth’s rotation balances the horizontal pressure gradient force. This flow is commonly observed in large-scale ocean currents and atmospheric circulation patterns. Understanding geostrophic flow is important in oceanography, meteorology, and the study of Earth’s climate systems.
Reference: Pedlosky, J. (1987). Geophysical Fluid Dynamics. Springer.

^GGeosyncline

A geosyncline is a large-scale depression in the Earth’s crust that fills with thick sequences of sedimentary and volcanic rocks, often associated with the early stages of mountain building. Geosynclines were once a central concept in geology, but they have been largely replaced by the modern theory of plate tectonics. However, they remain important in the historical study of tectonic processes and sedimentary basin evolution.
Reference: Dewey, J. F., & Bird, J. M. (1970). Mountain Belts and the New Global Tectonics. Journal of Geophysical Research.

^GGeothermal Energy

Geothermal energy is the heat derived from the Earth’s internal heat sources, which can be harnessed for electricity generation, direct heating, and other uses. It is a renewable energy resource that is particularly important in volcanic regions where geothermal gradients are high. The study of geothermal energy involves understanding the Earth’s heat flow, reservoir engineering, and the environmental impact of geothermal development.

Reference: Dickson, M. H., & Fanelli, M. (2004). Geothermal Energy: Utilization and Technology. Routledge.

^GGeothermal Gradient

The geothermal gradient is the rate at which the Earth’s temperature increases with depth, typically measured in degrees Celsius per kilometer. This gradient is a critical factor in the study of geothermal energy, the formation of magmas, and the thermal evolution of the Earth’s crust. It varies widely depending on tectonic setting, crustal composition, and heat flow.

Reference: Turcotte, D. L., & Schubert, G. (2002). Geodynamics. Cambridge University Press.

^GGeothermal Reservoir

A geothermal reservoir is a natural system that stores heat from the Earth’s interior, which can be tapped for geothermal energy production. These reservoirs typically consist of hot water or steam trapped in porous rocks. Understanding geothermal reservoirs is crucial for sustainable energy production, reservoir management, and environmental impact assessment.

Reference: Axelsson, G., & Gunnlaugsson, E. (2000). Long-Term Monitoring of High- and Low-Temperature Fields Under Exploitation. Proceedings World Geothermal Congress.

^GGeyser

A geyser is a hot spring that intermittently erupts jets of steam and hot water into the air. Geysers are powered by the geothermal heat from the Earth’s interior and are typically found in volcanic regions. They are significant in studying geothermal activity, volcanic processes, and the dynamics of hydrothermal systems.
Reference: Hurwitz, S., & Manga, M. (2017). The Fascinating and Complex Dynamics of Geyser Eruptions. Annual Review of Earth and Planetary Sciences.

^GGlacial Abrasion

Glacial abrasion is the process by which a glacier grinds down bedrock surfaces, using debris embedded in the ice as abrasive tools. This process creates striations, grooves, and polished surfaces, and plays a significant role in shaping glaciated landscapes. Studying glacial abrasion helps geologists understand past ice flow dynamics and erosion rates.

Reference: Boulton, G. S. (1974). Processes and Patterns of Glacial Erosion. Progress in Physical Geography.

^GGlacial Lake

A glacial lake is a body of water formed by the melting of glacial ice, often dammed by moraines, ice, or bedrock. These lakes are important indicators of past glacial activity, climate change, and the dynamics of glacial meltwater. Studying glacial lakes helps in understanding the processes of deglaciation, sedimentation, and landscape evolution.

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

^GGlacial Maximum

The glacial maximum refers to the period during an ice age when ice sheets reached their greatest extent, covering significant portions of the Earth’s surface. The most recent glacial maximum occurred about 20,000 years ago during the Last Glacial Period. Studying glacial maxima is crucial for understanding the Earth’s climatic history, ice sheet dynamics, and sea-level changes.

Reference: Clark, P. U., & Mix, A. C. (2002). Ice Sheets and Sea Level of the Last Glacial Maximum. Quaternary Science Reviews.

^GGlacial Moraine

A glacial moraine is an accumulation of unsorted glacial debris (till) that has been transported and deposited by a glacier. Moraines can form at the edges, terminus, or beneath the glacier, and are key indicators of past glacial activity, ice movement, and climatic conditions. Types of moraines include terminal, lateral, and medial moraines.

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

^GGlacial Outwash

Glacial outwash is a deposit of sand and gravel carried by meltwater from a glacier and laid down in stratified layers. Outwash plains, composed of these deposits, form in front of melting glaciers and are characterized by braided stream patterns. Studying glacial outwash provides insights into past glacial environments, sediment transport processes, and the interaction between glaciers and rivers.

Reference: Miall, A. D. (1970). A Review of the Geology of Glacial Outwash Plains. Bulletin of Canadian Petroleum Geology.

^GGlacial Plucking

Glacial plucking is the process by which a glacier removes large chunks of bedrock as it moves. This occurs when meltwater infiltrates bedrock fractures, freezes, and then as the glacier moves, it pulls the loosened rock fragments away. Plucking plays a key role in glacial erosion and the formation of jagged mountain landscapes.

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

^GGlacial Rebound

Glacial rebound, also known as isostatic rebound, is the rise of the Earth’s crust after the melting of a heavy ice sheet, which had previously caused the crust to depress. This process continues for thousands of years after the ice melts and is significant in studying the effects of glaciation on the Earth’s crust, sea-level changes, and post-glacial landscapes.

Reference: Peltier, W. R. (2004). Global Glacial Isostasy and the Surface of the Ice-Age Earth: The ICE-5G (VM2) Model and GRACE. Annual Review of Earth and Planetary Sciences.

^GGlacial Striation

Glacial striations are grooves or scratches carved into bedrock by rocks embedded in the base of a moving glacier. These striations are aligned with the direction of ice flow and provide important evidence of past glacial movement. Studying glacial striations helps geologists reconstruct ice flow patterns and understand the dynamics of ancient ice sheets.

Reference: Boulton, G. S. (1974). Processes and Patterns of Glacial Erosion. Progress in Physical Geography.

^GGlacial Till

Glacial till is an unsorted, unstratified mixture of sediments ranging from clay to boulders, deposited directly by glacial ice. It is significant in understanding past glacial environments, the dynamics of ice movement, and the geological history of glaciated regions. Till forms the basis for many glacial landforms, including moraines and drumlins.

Reference: Dreimanis, A. (1976). Tills: Their Genetic Terminology and Classification. Geological Society of America Bulletin.

^UArchives: Glossary

Uvula in geomorphology refers to a hanging tongue of rock, typically found in a karst cave environment. These formations are significant in the study of karst landscapes for understanding cave formation processes, speleogenesis, and the impact of chemical weathering on limestone.

Reference: Ford, D. C., & Williams, P. W. (2007). “Karst Hydrogeology and Geomorphology.” John Wiley & Sons.

Rocks

Glossary

F

Frost Heaving

F

Frost Wedging

F

Fumarole

G

Geochronology

G

Geodynamo

G

Geomorphology

G

Geopetal Structure

G

Geospeedometry

G

Geostrophic Flow

G

Geosyncline

G

Geothermal Energy

G

Geothermal Gradient

G

Geothermal Reservoir

G

Geyser

G

Glacial Abrasion

G

Glacial Lake

G

Glacial Maximum

G

Glacial Moraine

G

Glacial Outwash

G

Glacial Plucking

G

Glacial Rebound

G

Glacial Striation

G

Glacial Till

Pyroxene

FFrost Heaving

FFrost Wedging

FFumarole

GGeochronology

GGeodynamo

GGeomorphology

GGeopetal Structure

GGeospeedometry

GGeostrophic Flow

GGeosyncline

GGeothermal Energy

GGeothermal Gradient

GGeothermal Reservoir

GGeyser

GGlacial Abrasion

GGlacial Lake

GGlacial Maximum

GGlacial Moraine

GGlacial Outwash

GGlacial Plucking

GGlacial Rebound

GGlacial Striation

GGlacial Till

UArchives: Glossary

^FFrost Heaving

^FFrost Wedging

^FFumarole

^GGeochronology

^GGeodynamo

^GGeomorphology

^GGeopetal Structure

^GGeospeedometry

^GGeostrophic Flow

^GGeosyncline

^GGeothermal Energy

^GGeothermal Gradient

^GGeothermal Reservoir

^GGeyser

^GGlacial Abrasion

^GGlacial Lake

^GGlacial Maximum

^GGlacial Moraine

^GGlacial Outwash

^GGlacial Plucking

^GGlacial Rebound

^GGlacial Striation

^GGlacial Till

^UArchives: Glossary