Explosive eruptions are volcanic eruptions characterized by the violent expulsion of magma, gas, and ash, often resulting in significant destruction and hazards.
Soil formation is the process by which soil is developed from the weathering of rocks and the accumulation of organic material.
Lithification is the process by which loose sediment becomes sedimentary rock through compaction and cementation.
A light year is the distance that light travels in one year.
Cleavage refers to the tendency of a mineral to break along flat, even surfaces, while fracture describes the way a mineral breaks in an irregular manner.
Absolute hardness is a measure of a mineral's resistance to being scratched, differing from relative hardness which compares hardness between minerals.
A systematic approach to making observations, collecting data, and developing testable explanations or hypotheses about natural phenomena.
Pangea was a supercontinent that existed in the past, where all continents were assembled together.
Evidence for continental drift includes the fit of continents, glacial striations, fossil evidence like Mesosaurus, matching geological features, and paleoclimate evidence.
A Lahar is a type of volcanic mudflow that can travel many miles and poses a significant hazard during pyroclastic eruptions.
Hotspots are volcanic regions thought to be fed by underlying mantle plumes, which can create chains of volcanoes as tectonic plates move over them.
Paleomagnetism is the study of the Earth's magnetic field through geological time, providing evidence for plate tectonics.
Ocean ridges are underwater mountain ranges formed by plate tectonics, where new oceanic crust is created through volcanic activity.
Sedimentary layers refer to the distinct horizontal layers of sediment that accumulate over time, often reflecting changes in environmental conditions.
Mechanical weathering is the process of breaking down rocks into smaller pieces without changing their chemical composition.
Double chain silicates are a type of silicate mineral where tetrahedra are linked together in a chain formation, allowing for complex structures.
The central part of the Earth formed by heavy droplets of iron that percolated downward during the accretion process.
The three main volcanic settings are divergent boundaries, convergent boundaries, and intraplate settings, each characterized by different geological processes and types of volcanic activity.
Crystal habit is a general description of the appearance of crystals, which may include forms such as fibrous or bladed, rather than focusing solely on the individual crystal shape.
Pahoehoe lava is a type of basaltic lava that has a smooth, ropy surface, typically formed during low-viscosity eruptions.
A magnetic vector is a representation of the intensity and direction of the magnetic field, particularly in the northern hemisphere, directed toward the North Pole.
At subduction zones, one tectonic plate moves under another and sinks into the mantle, leading to melting and volcanic activity.
Glacial striations are scratches or grooves cut into bedrock by glacial movement, indicating past glacial activity.
Low viscosity magma is runny and typically basaltic in composition.
Large historical eruptions can lead to decreases in average temperature due to ash and gases circulating the globe, which decrease sunlight.
Oxidation is the increase in the valence state of a cation in a mineral, with iron (Fe) being the most common oxidizing cation.
Dikes are vertical tabular sheet-like bodies of magma that have been emplaced in the crust.
Magma is molten rock located beneath the Earth's surface that can solidify to form igneous rock.
Climate, particularly rainfall and temperature, significantly influences the rate of both mechanical and chemical weathering processes.
Paleomagnetism is the study of the magnetic properties of rocks, which helps in understanding the historical changes in the Earth's magnetic field and the movement of tectonic plates.
Water is involved in various chemical and physical weathering processes, facilitating reactions that lead to the breakdown of rocks.
The principle that geological processes we observe today have been operating throughout Earth's history, accounting for most geologic change.
Terrestrial planets are rocky planets with higher densities, typically found in the inner part of a solar system.
A tentative scientific explanation or prediction based on limited data that must be testable.
The Cascade Range is a mountain range in the Pacific Northwest of the United States, known for its volcanic activity, including notable volcanoes like Mount St. Helens.
Flood basalts are extensive volcanic rock formations created by the eruption of large volumes of basaltic lava, typically associated with hotspot activity.
Gases released during volcanic eruptions can have detrimental effects on human health, potentially causing respiratory issues and other health problems.
Plate velocities refer to the speed at which tectonic plates move, typically measured in centimeters per year.
A pluton is a crystallized magma chamber that solidifies at depth.
Chemical weathering is the chemical decomposition of rocks, which can include processes such as dissolution, oxidation, and hydrolysis.
Cementation is the process where water percolating through pore spaces deposits cementing minerals that bind sediment grains together.
The dip refers to the angle at which the wind is inclined, indicating the direction of the wind's movement.
It likely refers to the mathematical representation or analysis of current patterns, possibly in relation to wind or water flow.
Igneous rock forms from magma that has cooled and crystallized, either beneath the surface or as lava that flows at the surface.
Silicate minerals are a group of minerals that contain silicon and oxygen, and are the majority of minerals found in the continental crust.
Typical soil erosion factors include water runoff, wind, vegetation cover, and human activities such as agriculture and construction.
Chemical weathering involves the alteration of the chemical composition of rocks and minerals, often through reactions with water and other chemicals.
A phase diagram shows the stability of different states of matter (like ice, water, and vapor) at varying temperatures and pressures, which is crucial for understanding how melting occurs beneath the Earth's surface.
The process by which the Earth accretes and heats up, leading to the formation of its core, early crust, and a magma ocean.
A mineral assemblage refers to a group of minerals that occur together in a rock, reflecting the conditions under which the rock formed.
Igneous rock is classified based on its composition, which can be represented on a phase diagram.
Sheet silicates are silicate minerals where tetrahedra are linked into two-dimensional sheets, which can easily separate into thin layers.
Compaction is the process where the weight and pressure of overlying sediment compress deeper sediment, reducing pore space and facilitating lithification.
In geology, texture describes the size, shape, and arrangement of grains or crystals in a rock, which can indicate the rock's formation history.
Cleavage refers to the tendency of a mineral to break along flat, even surfaces, which can occur in specific directions.
A mineral is a naturally occurring inorganic substance with a specific chemical composition and a crystalline structure, distinct from rocks which are aggregates of one or more minerals.
The layer of the Earth that lies between the core and the crust, formed from lighter materials that rose to create the first crust.
Network silicates are silicate minerals where tetrahedra are linked in three-dimensional frameworks, resulting in very strong and durable structures.
The principle of apparent polar wander describes how the positions of the magnetic poles appear to change over time due to the movement of tectonic plates, rather than the actual movement of the poles themselves.
A vast body of molten rock that formed on the early Earth due to intense heating during its formation.
Calcite is a common mineral that exhibits three directions of cleavage and breaks along irregular surfaces.
Magnetic reversals are events in Earth's history when the magnetic field changes direction, causing the magnetic north and south poles to switch places.
Redshift is the phenomenon where light from an object is shifted to longer wavelengths, indicating that the object is moving away from the observer.
Seafloor spreading is the process by which new oceanic crust is created at mid-ocean ridges as magma rises to the surface, causing the tectonic plates to move apart.
The Ring of Fire is a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur, primarily due to tectonic plate boundaries.
Kilauea and Mauna Loa are two of the most active volcanoes in Hawaii, known for their frequent eruptions and lava flows, contributing to the volcanic landscape.
Diamond and graphite are both forms of carbon but are different minerals due to their distinct atomic arrangements, resulting in different physical properties.
A transform fault is a type of fault in plate tectonics where two tectonic plates slide past one another horizontally.
Transform faults are boundaries where two tectonic plates slide past each other horizontally, resulting in seismic activity.
Dissolution is the process of dissolving minerals in water or slightly acidic water, such as halite and calcite.
Sedimentary strata are layers of sedimentary rock that have been deposited over time, often characterized by distinct physical and chemical properties.
Sills are horizontal tabular sheet-like bodies of magma that have been emplaced at depth.
Nebular Theory is the model that describes the formation of solar systems from swirling clumps of matter called nebulae, which collapse to form stars and planets.
Aa lava is a type of basaltic lava that has a rough, jagged surface, formed from higher viscosity eruptions.
Jovian planets are gas giants with lower densities, typically found in the outer part of a solar system.
A caldera is a large depression formed when a volcano erupts and collapses, often resulting in a significant alteration of the landscape.
The solidus is the temperature below which a material is completely solid, and above which it begins to melt.
Changes in magma composition from mafic to intermediate to felsic occur with decreasing temperature and crystallization, affecting the type of volcanic rock formed.
Magma viscosity is a function of temperature and silica content; higher temperature and lower silica content result in less viscous magma.
Hydrolysis is the process where H+ in water replaces positive ions in silicates, resulting in a change in mineral structure.
The concept that changes in the Earth's landscape occur slowly over time, rather than through sudden, catastrophic events.
Positive ions, such as silicon, are abundant in minerals and contribute to their structural characteristics.
Pillow lava is a type of lava that forms underwater, characterized by its rounded, pillow-like shapes, indicating that it erupted beneath the surface of a body of water.
Divergent plate boundaries are locations where two tectonic plates move apart, typically found at mid-ocean ridges where new ocean crust is created.
Convergent plate boundaries are areas where two tectonic plates collide, leading to subduction zones where one plate dives beneath another, or where both plates collide without subduction.
Wegener's theory was not accepted because he could not provide a plausible mechanism for how continents could move across the globe.
Weathering is the disintegration and decomposition of rocks at the Earth's surface.
A batholith is a large body of intrusive igneous rock that forms from many plutons at depth.
A subduction zone is a geological area where one tectonic plate moves under another and sinks into the mantle, often leading to volcanic activity.
Color is an important optical property in mineral identification; some minerals have a consistent color, while others may vary due to impurities, such as corundum which can be red (ruby) or blue (sapphire).
Seafloor spreading is the process by which new oceanic crust is formed at mid-ocean ridges and gradually moves away from the ridge, as supported by Hess's ideas and measurements of magnetic reversals.
Crystallization in a crustal magma chamber refers to the process where magma cools and solidifies, forming minerals and altering the composition of the remaining melt.
Hubble discovered that the farther away a galaxy is, the more redshifted its light, indicating that the universe is expanding.
Chemical weathering is the process where minerals dissociate into constituent elements, sometimes forming new minerals, often facilitated by water and higher temperatures, and is most efficient in warm, moist climates.
Mantle convection is the slow creeping motion of the Earth's mantle caused by convection currents carrying heat from the interior of the Earth to the surface.
Mechanical weathering is the physical disaggregation and breaking apart of rocks without changing their chemical composition.
The main division of minerals is between silicates, which contain silicon, and non-silicates, which do not.
Hotspots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle.
An outdated astronomical theory that places the Earth at the center of the universe, with all celestial bodies orbiting around it.
The phenomenon where light from distant galaxies shifts toward longer wavelengths, indicating that they are moving away from us.
Alfred Wegener proposed the theory of continental drift.
High viscosity magma is thick and is often associated with intermediate magmas.
Detrital sedimentary structures are features formed by the accumulation and compaction of particles derived from the weathering and erosion of pre-existing rocks.
Sedimentary beds are individual layers of sedimentary rock that are typically distinguished by differences in composition, texture, or color.
