Glossary

Quartz

Fact Sheet:
– Chemical Composition: SiO₂ (Silicon Dioxide)
– Hardness: 7 on the Mohs scale
– Crystal System: Hexagonal
– Color Varieties: Clear, white, pink (rose quartz), black (smoky quartz), purple (amethyst), yellow (citrine), and others
– Major Localities: Brazil, Madagascar, the United States, and the Alps in Europe
Common Uses: Jewelry, electronic components, and as a decorative stone in construction

Introduction: Quartz, one of the most abundant minerals on the Earth’s surface, forms a key component of continental crust. Known for its durability and wide range of colors, quartz serves both aesthetic and functional purposes, making it a cornerstone ...

^LLaterite

Laterite is a highly weathered soil rich in iron and aluminum oxides, typically found in tropical regions with high rainfall. Laterites are often used as a source of iron ore and as a building material. They are significant in soil science and the study of tropical weathering processes.

Reference: Tardy, Y. (1997). “Petrology of Laterites and Tropical Soils.” CRC Press.

^LLava Dome

A lava dome is a rounded, steep-sided mound that forms when viscous lava extrudes slowly from a volcanic vent. Lava domes are significant in studying volcanic hazards, as they can produce pyroclastic flows, lava flows, and explosive eruptions when they collapse or are disrupted.

Reference: Fink, J. H. (1983). “Structure and Evolution of a Rhyolitic Obsidian Flow: Little Glass Mountain, Medicine Lake Highland, Northern California.” Geological Society of America Bulletin, 94(4), 362-380.

^LLava Flow

A lava flow is a mass of molten rock that moves across the Earth’s surface during a volcanic eruption. Lava flows can vary in composition, viscosity, and temperature, influencing their behavior and impact on the landscape. Studying lava flows is important for understanding volcanic processes, hazards, and the formation of volcanic landforms.

Reference: Kilburn, C. R. J., & Luongo, G. (1993). “Active Lava Flows: Monitoring and Modelling.” UCL Press.

^LLava Plateau

A lava plateau is a large, flat expanse of land formed by the eruption of large volumes of low-viscosity basaltic lava that spreads over a vast area. These plateaus are significant in understanding volcanic processes, flood basalt events, and the formation of large igneous provinces.

Reference: Thordarson, T., & Self, S. (1998). “The Roza Member, Columbia River Basalt Group: A Giant Flood Basalt Eruption.” Journal of Geophysical Research: Solid Earth, 103(B11), 27411-27445.

^LLava Tube

A lava tube is a natural tunnel formed by flowing lava beneath the surface of a solidified lava flow. Lava tubes are significant in understanding volcanic processes, the movement of lava flows, and the formation of volcanic landforms. They can also serve as habitats for unique ecosystems.

Reference: Peterson, D. W., & Swanson, D. A. (1974). “Observations of Lava Tubes, Kilauea Volcano, Hawaii.” Bulletin Volcanologique, 38(1), 144-156.

^LLevee

A levee is a natural or artificial embankment that parallels a river, preventing the river from flooding the adjacent land. Natural levees form during flood events when sediment is deposited along the river’s edges, while artificial levees are constructed to protect against flooding. Levees are significant in flood management and the study of fluvial processes.

Reference: Smith, N. D. (1986). “River Levees.” In: Richards, K. S. (Ed.), River Channels: Environment and Process. Blackwell, pp. 391-433.

^LLichenometry

Lichenometry is a geochronological technique that uses the size of lichen colonies to estimate the age of exposed rock surfaces, particularly in glacial and periglacial environments. This method is valuable in studying the timing of glacial retreat, rockfall events, and other geomorphological processes.

Reference: Innes, J. L. (1985). “Lichenometry.” Progress in Physical Geography, 9(2), 187-254.

^LLignite

Lignite is a low-grade, brownish-black coal that represents an intermediate stage between peat and bituminous coal. It has a relatively low carbon content and high moisture content, making it less efficient as a fuel. Lignite is significant in studying the formation of coal, paleoenvironments, and the carbon cycle.

Reference: Taylor, G. H., Teichmüller, M., Davis, A., Diessel, C. F. K., Littke, R., & Robert, P. (1998). “Organic Petrology: A New Handbook Incorporating Advances in the Understanding of Organic Matter and Fossil Fuels.” Gebrüder Borntraeger.

^LLimestone

Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3), typically formed in marine environments from the accumulation of shell, coral, algal, and fecal debris. It is a key rock in the carbon cycle and is widely used in construction, agriculture, and industry. Limestone is important in understanding sedimentary environments and the geological history of carbonates.

Reference: Tucker, M. E., & Wright, V. P. (1990). “Carbonate Sedimentology.” Blackwell Science.

^LLithification

Lithification is the process by which sediments are compacted and cemented to form solid sedimentary rock. This process involves the reduction of pore space and the precipitation of minerals that bind the sediment grains together. Lithification is crucial in the formation of sedimentary rocks and the preservation of fossils.

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

^LLithologic Discontinuity

Lithologic discontinuity refers to a boundary within a rock sequence where there is a significant change in rock type, such as between sandstone and shale. These discontinuities are important in stratigraphy for interpreting depositional environments, correlating rock layers, and understanding the geological history of an area.

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

^LLithologic Facies

Lithologic facies are distinct rock units that form under specific conditions of deposition, reflecting particular environments such as a delta, reef, or desert. Identifying and interpreting facies is essential for reconstructing past environments, understanding sedimentary processes, and exploring natural resources.

Reference: Reading, H. G. (1996). “Sedimentary Environments: Processes, Facies and Stratigraphy.” Blackwell Science.

^LLithologic Logging

Lithologic logging is the process of systematically recording the lithology, or rock types, encountered in a borehole or outcrop. This information is critical in geological exploration, resource assessment, and understanding subsurface geology, including the identification of potential hydrocarbon reservoirs.

Reference: Rider, M. H., & Kennedy, M. (2011). “The Geological Interpretation of Well Logs.” Rider-French Consulting Ltd.

^LLithosphere

The lithosphere is the rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle. It is divided into tectonic plates that move and interact at their boundaries, driving geological processes such as earthquakes, volcanism, and mountain building. The lithosphere is crucial in understanding plate tectonics and Earth’s dynamic processes.

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

^LLithosphere Mantle

The lithosphere mantle is the portion of the Earth’s mantle that lies beneath the lithosphere’s crust and is part of the rigid outer shell of the Earth. It plays a key role in plate tectonics, as the lithospheric plates are composed of both crust and lithospheric mantle. Understanding its composition and behavior is essential for studying mantle dynamics and plate movements.

Reference: Anderson, D. L. (2007). “New Theory of the Earth.” Cambridge University Press.

^LLithosphere-Asthenosphere Boundary (LAB)

The Lithosphere-Asthenosphere Boundary (LAB) is the depth at which the Earth’s rigid lithosphere transitions into the more ductile asthenosphere. This boundary is critical in understanding plate tectonics, as it marks the zone where tectonic plates move over the more fluid asthenosphere, influencing the dynamics of plate movement.

Reference: Schubert, G., Turcotte, D. L., & Olson, P. (2001). “Mantle Convection in the Earth and Planets.” Cambridge University Press.

^LLithospheric Flexure

Lithospheric flexure refers to the bending of the Earth’s lithosphere under the weight of an overlying load, such as a mountain range, ice sheet, or volcanic island. This process is important in understanding isostatic adjustments, the formation of foreland basins, and the structural response of the lithosphere to loading and unloading events.

Reference: Watts, A. B. (2001). “Isostasy and Flexure of the Lithosphere.” Cambridge University Press.

^LLithospheric Plates

Lithospheric plates are large, rigid sections of the Earth’s lithosphere that move over the more ductile asthenosphere. The interaction of these plates at their boundaries results in significant geological phenomena, including earthquakes, volcanic activity, and mountain building. The study of lithospheric plates is fundamental to the theory of plate tectonics.

Reference: Gordon, R. G. (1998). “The Plate Tectonic Approximation: Plate Nonrigidity, Diffuse Plate Boundaries, and Global Plate Reconstructions.” Annual Review of Earth and Planetary Sciences, 26(1), 615-642.

^LLittoral Zone

The littoral zone is the part of a sea, lake, or river that is close to the shore and extends from the high-water mark to the area where sunlight penetrates to the sediment, allowing aquatic plants to grow. This zone is critical for studying coastal processes, ecosystems, and the impact of human activities on nearshore environments.

Reference: Wetzel, R. G. (2001). “Limnology: Lake and River Ecosystems.” Academic Press.

^MMafic Dike

A mafic dike is a sheet-like intrusion of mafic magma that cuts through existing rock layers. Dikes are important in understanding the processes of magma emplacement, the mechanics of crustal extension, and the formation of volcanic and plutonic rock bodies.

Reference: Best, M. G. (2003). “Igneous and Metamorphic Petrology.” Wiley-Blackwell.

^MMafic Intrusion

A mafic intrusion is an igneous body composed predominantly of mafic minerals, such as pyroxene and olivine, that has intruded into the Earth’s crust. These intrusions are significant for studying the processes of magma emplacement, the formation of ore deposits, and the thermal evolution of the crust.

Reference: Best, M. G. (2003). “Igneous and Metamorphic Petrology.” Wiley-Blackwell.

^MMafic Lava

Mafic lava is a type of lava that is rich in magnesium and iron, typically forming basaltic rocks. It is relatively low in silica, which makes it less viscous and allows it to flow more easily than felsic lava. Mafic lava is significant in the formation of oceanic crust, volcanic islands, and large igneous provinces.

Reference: Best, M. G. (2003). “Igneous and Metamorphic Petrology.” Wiley-Blackwell.

^MMafic Magma

Mafic magma is a type of magma that is rich in magnesium and iron and has a low silica content. It is typically less viscous than felsic magma and is associated with the formation of basaltic rocks. Mafic magma plays a significant role in the formation of oceanic crust and basaltic lava flows.

Reference: Wilson, M. (1989). “Igneous Petrogenesis: A Global Tectonic Approach.” Unwin Hyman.

^TArchives: Glossary

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.