Glossary

Magnetite

Fact Sheet:
– Chemical Composition: Fe₃O₄ (Iron(II,III) Oxide)
– Hardness: 5.5 to 6.5 on the Mohs scale
– Crystal System: Isometric
– Color Varieties: Black to brownish-black with a metallic luster
– Major Localities: Australia, Brazil, Canada, and the United States
– Common Uses: Iron ore, magnetic materials, and catalysts

Introduction: Magnetite is a fascinating mineral known for its strong magnetic properties, which are unique among naturally occurring minerals. Its name comes from Magnesia, a region in Greece where the mineral was first discovered. Beyond its magnetic allure, magnetite is a crucial iron ore and has various industrial applications.

Formation: ...

^PPaleotemperature

Paleotemperature refers to the temperature conditions in past geological periods, reconstructed from various proxies such as ice cores, tree rings, and isotopic compositions in sediments. This information is crucial for understanding past climate variability, the Earth’s thermal history, and the factors influencing global temperatures over geological time.

Reference: Bradley, R. S. (1999). “Paleoclimatology: Reconstructing Climates of the Quaternary.” Academic Press.

^PPegmatite

Pegmatite is an exceptionally coarse-grained igneous rock, typically composed of quartz, feldspar, and mica. These rocks form during the final stages of magma crystallization and often contain rare minerals, making them important for studying the late-stage processes of magma evolution and for the extraction of rare elements like lithium and tantalum.

Reference: London, D. (2008). “Pegmatites.” Canadian Mineralogist Special Publication 10.

^PPeneplain

A peneplain is a low-relief land surface that results from prolonged erosion and denudation, representing the final stage of landscape evolution before uplift or rejuvenation. Peneplains are significant for understanding long-term geomorphic processes, landscape evolution, and the history of continental surfaces.

Reference: Penck, W., & King, L. C. (1953). “Geomorphology.” Macmillan.

^PPermafrost

Permafrost is permanently frozen ground that remains at or below 0°C for at least two consecutive years. It is found in polar regions and high-altitude areas and plays a critical role in the Earth’s climate system, particularly in the carbon cycle, as it stores large amounts of organic carbon that can be released as greenhouse gases when thawed.

Reference: Brown, J., et al. (1998). “Circumpolar Active Layer Monitoring (CALM) Program: Description and Data.” CD-ROM. National Snow and Ice Data Center.

^PPhreatic Eruption

A phreatic eruption, also known as a steam-blast eruption, occurs when groundwater comes into contact with hot magma or lava, causing it to rapidly vaporize and explode. These eruptions are important for understanding volcanic hazards, particularly in areas with abundant groundwater or near hydrothermal systems.

Reference: Mastin, L. G. (1995). “Thermohydraulic Modeling of the Surface Eruptions at Mount St. Helens, 1980-1984.” Bulletin of Volcanology, 57(6), 509-516.

^QQuasi-Geoid

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.

^QQuicksand

Quicksand is a colloid hydrogel consisting of fine granular material (such as sand), clay, and water. It behaves like a liquid when agitated but can trap objects due to its inability to support weight. Quicksand is significant in sedimentology and soil mechanics for understanding fluidized sedimentary layers and their impact on construction and land stability.

Reference: Dunn, I. S., Anderson, L. R., & Kiefer, F. W. (1980). “Fundamentals of Geotechnical Analysis.” Wiley.

^QQuicksilver

Quicksilver is another name for mercury, a heavy, silvery metal that is liquid at room temperature. It is significant in the study of mineral deposits, particularly cinnabar (mercury sulfide), which is the primary ore for mercury extraction, as well as for understanding its environmental and health impacts.

Reference: Hylander, L. D., & Meili, M. (2003). “500 Years of Mercury Production: Global Annual Inventory by Region Until 2000 and Associated Emissions.” Science of the Total Environment, 304(1-3), 13-27.

^QQuiescent Volcano

A quiescent volcano is one that is currently inactive but has the potential to erupt again. These volcanoes are significant for volcanic hazard assessment, as they can remain dormant for long periods before erupting, posing risks to nearby populations.

Reference: Simkin, T., & Siebert, L. (1994). “Volcanoes of the World.” Smithsonian Institution.

^RRadial Drainage Pattern

A radial drainage pattern is a network of streams that radiate outward from a central point, typically associated with volcanic cones or domes. This pattern is significant in geomorphology for understanding the influence of topography on drainage development and the geological history of volcanic regions.

Reference: Chorley, R. J., Schumm, S. A., & Sugden, D. E. (1984). “Geomorphology.” Methuen.

^RRadiocarbon Dating

Radiocarbon dating is a method for determining the age of organic materials by measuring the decay of carbon-14. This technique is essential in archaeology, paleontology, and geology for dating relatively recent events up to about 50,000 years ago.

Reference: Taylor, R. E. (1987). “Radiocarbon Dating: An Archaeological Perspective.” Academic Press.

^RRadiolarian Chert

Radiolarian chert is a sedimentary rock composed predominantly of silica, formed from the accumulation of radiolarian skeletons. These rocks are significant in paleontology and stratigraphy for understanding deep-sea environments, the global carbon cycle, and the age dating of oceanic crust.

Reference: Moore, T. C. (1973). “Radiolarian Stratigraphy and the Cenozoic History of the Equatorial Pacific.” Geological Society of America Bulletin, 84(5), 1803-1828.

^RRadiometric Dating

Radiometric dating is a method used to determine the age of rocks, minerals, and fossils by measuring the relative proportions of radioactive isotopes and their decay products. This technique is crucial for establishing the absolute ages of geological formations and the timing of events in Earth’s history, such as the age of the Earth, volcanic eruptions, and fossils.

Reference: Faure, G. (1986). “Principles of Isotope Geology.” Wiley.

^RRedox Potential

Redox potential (Eh) is a measure of the tendency of a chemical environment to either gain or lose electrons, influencing the oxidation-reduction reactions that occur in it. In geology, redox potential is significant for understanding the formation of minerals, the mobility of metals, and the geochemistry of natural waters.

Reference: Langmuir, D. (1997). “Aqueous Environmental Geochemistry.” Prentice Hall.

^RReservoir Rock

Reservoir rock is a porous and permeable rock that can contain and transmit fluids, typically oil or gas, making it a key component in hydrocarbon exploration and production. These rocks are crucial in petroleum geology for understanding the accumulation and extraction of oil and gas.

Reference: Schlumberger (1989). “Reservoir Characterization.” Elsevier.

^RResidual Soil

Residual soil is soil that forms in place from the weathering of the underlying rock, without significant transport. These soils are important for understanding weathering processes, soil formation, and landscape development, particularly in regions with stable tectonic conditions.

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

^RResistivity Survey

A resistivity survey is a geophysical method used to measure the electrical resistance of subsurface materials, helping to identify variations in rock types, groundwater, and mineral deposits. This method is important for exploration geophysics, environmental studies, and engineering applications.

Reference: Telford, W. M., Geldart, L. P., & Sheriff, R. E. (1990). “Applied Geophysics.” Cambridge University Press.

^RReverse Fault

A reverse fault is a type of fault where the hanging wall moves upward relative to the footwall, typically due to compressional forces. These faults are significant for understanding the processes of crustal shortening and the formation of mountain ranges, as they are commonly found in convergent tectonic settings.

Reference: Twiss, R. J., & Moores, E. M. (2007). “Structural Geology.” W. H. Freeman.

^RRhyolitic Lava

Rhyolitic lava is a highly viscous, silica-rich lava that typically forms steep-sided domes or flows. It is significant in volcanology for understanding the explosive nature of rhyolitic eruptions, the formation of volcanic domes, and the processes that lead to the buildup of pressure in magma chambers.

Reference: Macdonald, G. A. (1972). “Volcanoes.” Prentice Hall.

^RRift Flank

A rift flank is the elevated region that forms on either side of a rift valley due to the extensional forces that create the rift. Rift flanks are significant for understanding the tectonic processes that lead to continental breakup, the development of rift basins, and the uplift and erosion of the Earth’s crust.

Reference: Ebinger, C. J. (2005). “Continental Breakup: The East African Perspective.” Geophysical Monograph Series, 148, 305-324.

^RRift Valley

A rift valley is a large, elongated depression formed by the extension and pulling apart of the Earth’s crust. These valleys are significant for understanding tectonic processes, particularly the early stages of continental breakup, the formation of new ocean basins, and the development of volcanic and seismic activity along rift zones.

Reference: Rosendahl, B. R. (1987). “Architecture of Continental Rifts with Special Reference to East Africa.” Annual Review of Earth and Planetary Sciences, 15, 445-503.

^RRift Zone

A rift zone is a region of the Earth’s crust where tectonic plates are diverging, leading to the formation of rifts and the potential development of new ocean basins. Rift zones are significant for understanding the processes of continental breakup, seafloor spreading, and the formation of volcanic and geothermal features.

Reference: Ebinger, C. J., & Casey, M. (2001). “Continental Breakup in Magma-Rich and Magma-Poor Rifts: Evolution of the East African Rift System.” Journal of African Earth Sciences, 30(4), 815-834.

^RRipple Marks

The rock cycle is a conceptual model describing the transformation of rocks through various geological processes, including the formation of igneous, sedimentary, and metamorphic rocks. This cycle is crucial for understanding the dynamic nature of Earth’s crust and the processes that recycle materials over geological time scales.

Reference: Skinner, B. J., & Porter, S. C. (2004). “The Dynamic Earth: An Introduction to Physical Geology.” Wiley.

^SArchives: Glossary

A stratovolcano, also known as a composite volcano, is a large, steep volcano built up of alternating layers of lava, ash, and volcanic debris. These volcanoes are significant in volcanology for understanding explosive eruptions, volcanic hazards, and the formation of volcanic arcs.

Reference: Davidson, J. P., et al. (2007). “The North Atlantic Igneous Province: Stratigraphy, Tectonics, Volcanism.” Cambridge University Press.

Rocks

Glossary

P

Paleotemperature

P

Pegmatite

P

Peneplain

P

Permafrost

P

Phreatic Eruption

Q

Quasi-Geoid

Q

Quicksand

Q

Quicksilver

Q

Quiescent Volcano

R

Radial Drainage Pattern

R

Radiocarbon Dating

R

Radiolarian Chert

R

Radiometric Dating

R

Redox Potential

R

Reservoir Rock

R

Residual Soil

R

Resistivity Survey

R

Reverse Fault

R

Rhyolitic Lava

R

Rift Flank

R

Rift Valley

R

Rift Zone

R

Ripple Marks

Magnetite

PPaleotemperature

PPegmatite

PPeneplain

PPermafrost

PPhreatic Eruption

QQuasi-Geoid

QQuicksand

QQuicksilver

QQuiescent Volcano

RRadial Drainage Pattern

RRadiocarbon Dating

RRadiolarian Chert

RRadiometric Dating

RRedox Potential

RReservoir Rock

RResidual Soil

RResistivity Survey

RReverse Fault

RRhyolitic Lava

RRift Flank

RRift Valley

RRift Zone

RRipple Marks

SArchives: Glossary