MTEL GEOLOGY

PHYSICAL CHARACTERISTICS USED TO IDENTIFY AND CLASSIFY MINERALS

1. Color* 2. Luster* 3. Streak* 4. Hardness* 5. Cleavage* 6. Fracture* 7. Density* 8. Crystal Systems* 9. Tenacity 10. Habit 11. Specific Gravity 12. Magnetism 13. Fluorescence 14. Reactivity to acid 15. Striations 16. Taste

TWO MAIN SOURCES OF TECTONIC PLATE MOTION

1. Gravity 2. Friction

SUPPORT FOR THE THEORY OF PLATE TECTONICS

1. Shape of the continents 2. Paleomagnetism 3. Age of rock at mid-ocean ridges 4. Climatology 5. Evidence of rock units 6. Topographic evidence 7. Fossil evidence 8. Sea turtle migration

FOUR GENERAL CATEGORIES OF SEDIMENTS

1. Solid particles: Fragmented by-products of weathering consisting of fragmented rocks produced by mechanical weathering, as well as materials produced by chemical weathering such as sand, gravel, and silt. These sediments provide clues about their origin. 2. Fine-grained clay minerals: 3. Ions and salt by products: 4. Organic

CLASSIFICATION OF METAMORPHIC ROCKS

1. Texture/Grain size

INNER CORE

A dense ball of solid metal (nickel & iron).

OUTER CORE

A layer of molten metal (nickel & iron) that surrounds the inner core. Scientists think that movements in the liquid of this layer are responsible for Earth's magnetic field.

IRREGULAR FRACTURE

A rough, uneven surface fracture.

VOLCANO

A weak spot in the crust, usually at plate boundaries, where molten material, or magma, comes to the surface.

CONGLOMERATES

Clastic rocks formed from the compaction and cementation of gravel fragments ranging in diameter from a few mm to several m.

HARDNESS

Describes how hard a mineral is; Based upon the arrangement of atoms within the crystalline structure.

CONNATE FLUID

Liquids trapped within sedimentary rocks.

ISOSTATIC REBOUND

Occurs when a load is imposed on or removed from the lithosphere. The surface tends to rise or sink as the lithosphere rises or sinks in the asthenosphere. Loads may consist of large lakes, oceans (on continental shelves during eustatic sea level rise), ice, sediment, thrust sheets, and volcanoes. The rising or sinking of the lithosphere will continue until isostatic equilibrium is reached.

HACKLY FRACTURE

Refers to a line of fracture with sharp, jagged edges.

EXTRUSIVE IGNEOUS ROCK

Rock that forms when magma reaches the Earth's surface and quickly cools, forming small, fine-grained crystals or, in some cases, no crystals at all (obsidian). Basalt, the most abundant type of this rock, makes up most of the oceanic crust, shield volcanoes, & lava plateaus.

DIRECTED PRESSURE

The pressure that is enforced in a certain direction due to orogenesis and is responsible for foliation.

FLUORESCENCE

The special property that some minerals, such as Lapis Lazuli and scheelite, have that causes them to glow under UV light.

MAGNETISM

The special property that some minerals, such as magnetite, have that causes them to be magnetic.

SEISMOLOGY

The study of earthquakes.

EARTHQUAKE

Vibrations caused by breaking rock along faults; most result from plates moving over, under, and past each other.

LAYERS OF THE EARTH

1. Crust (0-35 km below surface) 2. Mohorovicic Discontinuity (30-70 km below continental crust & 6-8 km below oceanic crust) 3. Mantle (35-2,890 km below surface) 4. Lithosphere (0-60 km before surface) 5. Asthenosphere (100-700 km below surface) 6. Mesosphere (900-2,800 km below surface) 7. Outer Core (2,890-5,100 km below surface) 8. Inner Core (5,100-6,378 km below surface)

FACTORS AFFECTING THE DISTRIBUTION OF SEDIMENTS IN OCEANIC BODIES

1. Distance from land 2. Water depth 3. Physical and chemical properties of the water 4. local plant and animal life

EVIDENCE FOR SEA-FLOOR SPREADING

1. Eruptions of molten material 2. Magnetic stripes in the rock of the ocean floor 3. Ages of the rocks (drilling samples)

TWO PRIMARY DRIVING FORCES BEHIND METAMORPHISM

1. Heat 2. Pressure The degree of metamorphism depends on the magnitude of the heat and/or pressure applied. Rocks do not melt during metamorphism, they are simply baked into a new substance.

EVIDENCE FOR CONTINENTAL DRIFT

1. Land features--mountain ranges in S.A. & Africa, coal fields in Europe & N.A. 2. Fossils--species found in distant locations 3. Climate change--fossils of species from former climates found in present day climates

CLASSIFICATION OF IGNEOUS ROCKS

1. Origin 2. Texture / Grain Size 3. Mineral / Chemical Composition

THREE GENERAL SUBDIVISIONS OF PALEONTOLOGY

1. Paleozoology & Paleoanthropology 2. Paleobotany 3. Micropaleontology

ZONES OF MARINE SEDIMENT DEPOSITION

1. Shore Zone: Tidal activity deposits coarse materials, such as sand and gravel, where waves break against the shore. 2. Continental Shelf: Sediments from land, such as clays and silts, are deposited on this broad shelf where algae and coral play active roles in the formation of sedimentary rock. 3. Continental Slope: The downward incline from the continental shelf to the ocean floor. 4. Ocean Floor/Abyss: Where the finest sediments accumulate.

THEORY OF PLATE TECTONICS

1. States that the 10 plates of Earth's lithosphere are in slow, constant motion, driven by convection currents in the mantle. These plates abut one another at plate boundaries where the formation of topological features of Earth's surface begins. This theory explains the formation, movement, and subduction of Earth's plates. 2. Arose from the fusion of Continental Drift (first proposed by Wegener in 1915) and seafloor spreading (refined by Hess and Dietz in the early 1960s). Confirmed in the 1960s after the identification and study of the Mid-Atlantic Ridge and magnetic striping. This theory provides an explanation for the empirical observations of continental drift and seafloor spreading.

MINERALS OF MOHS HARDNESS SCALE

1. Talc 2. Gypsum-- easily scratched by a fingernail 3. Calcite--a fingernail can't scratch it, but a copper penny can 4. Fluorite--can be easily scratched by a steel knife 5. Apatite--can be scratched by a steel knife 6. Feldspar--can't be scratched by a steel knife, but can scratch window glass 7. Quartz--can easily scratch steel and hard glass 8. Topaz 9. Corundum 10. Diamond--hardest known mineral; can scratch all other substances

ISOSTASY

1. The equilibrium that exists between parts of the earth's crust, which behaves as if it consists of blocks floating on the underlying mantle, rising if material (such as an ice cap) is removed and sinking if material is deposited. 2. The state of gravitational equilibrium between Earth's lithosphere and asthenosphere that allows the solid tectonic plates to float on the more liquid asthenosphere at an elevation dependent on their thickness and density.

DENUDATION

1. The long-term sum of processes that cause the wearing away of the Earth's surface by moving water, ice, wind and waves, leading to a reduction in elevation and relief of landforms and landscapes. 2. The process by which elevation and relief in landscapes is reduced through the removal of material by erosion and weathering.

COMMON PROTOLITHS

1. slate was shale or mudstone 2. granite was diorite to gneiss 3. quartzite was quartz sandstone

FOLIATED

A banded or striped appearance to the naked eye; Refers to repetitive layering in metamorphic rocks, with each layer possibly being a thin as paper or over a m in thickness; Usually results from regional metamorphism. Examples: gneiss--very obvious striped banding (highly foliated), schist--flaky appearance, tends to be shiny like there is glitter stuck all over the rock's surface (medium foliated), slate--cleavage with a slight sheen (slightly foliated).

PETROGRAPHY

A branch of petrology that focuses on detailed physical descriptions in order to identify and classify the rock.

PEDIMENT

A broad, gently sloping expanse of rock debris extending outward from the foot of a mountain slope, especially in a desert.

LOPOLITH

A concordant body with a roughly flat base and convex top, usually with a feeder pipe below; A large igneous intrusion which is lenticular (convex on both sides) in shape with a depressed central region. These features are generally concordant with the intruded strata with dike or funnel-shaped feeder bodies below the body.

VOLCANIC NECK

A deposit of hardened magma in a volcanic pipe; A column of igneous rock formed by congelation of lava in the conduit of a volcano and later exposed by the removal of surrounding rock.

SEISMOGRAPH / SEISMOMETER

A device that records and measures the ground movements caused by seismic waves as they move through Earth; Movements are displayed as a series of lines on a recording chart called a seismogram, which shows the seismic energy detected at a particular location;

BED

A division of a geologic formation or stratigraphic rock series that is thicker than one cm marked by well-defined divisional planes (bedding planes) separating it from layers above and below.

DELTA

A fan of braided streams and sediment formed when a river discharges into a larger body of water, such as a gulf.

UNDULATION

A flowing, up-and-down movement like the motion of waves.

SYNCLINE

A fold in rock that bends downward to form a valley; ound in places where compression forces have caused crustal folding due to plate movement; Example: central Appalachian Mountains in PA are folded mountains

ANTICLINE

A fold in rock that bends upward into an arch; found in places where compression forces have caused crustal folding due to plate movement; Example: central Appalachian Mountains in PA are folded mountains

MOLD FOSSILS / TYPOLITES

A fossil formed when an organism dies and is covered by sediment, its flesh decays and bones deteriorate due to chemical reactions and a cavity remains below the ground surface; Created when the dissolution of carcasses leave an impression in rock; A stone or fossil bearing impressions of organisms.

GEOLOGIC FAULT

A fracture in Earth's surface created by movement of the crust. Most are found along plate boundaries.

PENEPLAIN

A gently undulating, almost featureless plain that, in principle, would be produced by fluvial erosion that would, in the course of geologic time, reduce the land almost to baselevel (sea level), leaving so little gradient that essentially no more erosion could occur. The concept was named in 1889 by William M. Davis, who believed it to be the final stage of his geomorphic cycle of landform evolution.

RIFT VALLEY

A large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems; A lowland region that forms where Earth's tectonic plates move apart, or rift. They are found both on land and at the bottom of the ocean, where they are created by the process of seafloor spreading.

BATHOLITH

A large irregular discordant igneous intrusion that forms from the cooling of a large body of magma deep within Earth's crust. These structures are usually ancient solidified magma chambers that have been exposed through weathering and erosion. An example is Stone Mountain in GA. These features are commonly composed of coarse-grained rocks with a surface exposure of 100 square km or larger with an irregular shape and side walls that incline steeply against the host rock. Most intrude across mountain folds and are elongated along the dominant axis of the range.

RICHTER SCALE

A logarithmic scale (a 5.0 EQ is 10x stronger than a 4.0 EQ, and 100x stronger than a 3.0 EQ) that rates an earthquake's magnitude based on the size of its seismic waves; accurate for small, nearby earthquakes but does not work well otherwise;

SUBDUCTION ZONE

A long, narrow belt where a lithospheric plate dives into the asthenosphere. The rate of subduction is relatively equal to the rate of formation (at mid-ocean ridges), thus the ocean floor recycles itself.

CLEAVAGE

A mineral's ability to easily split along flat surfaces. Whether a mineral has this property depends on how the atoms in its crystals are arranged. Examples: mica, feldspar

MAGMA

A molten mixture of rock-forming substances, gases, and water from the mantle.

MINERAL

A naturally occurring, inorganic solid that has a regular atomic (crystalline) structure and a definite homogenous chemical composition. Some, such as diamond, are single elements (carbon), while others, such as halite (NaCl) and pyrite (FeS4) are simple combinations of atoms, and still others, such as tourmaline, are more complex.

PHACOLITH

A pluton parallel to the bedding plane or foliation of folded country rock. More specifically, it is a typically lens-shaped pluton that occupies either the crest of an anticline or the trough of a syncline; A concordant lens-shaped pluton that typically occupies the crest of an anticline or trough of a syncline.

RIDGE-PUSH GRAVITY / SLIDING PLATE FORCE

A proposed mechanism for plate motion in plate tectonics. Because mid-ocean ridges lie at a higher elevation than the rest of the ocean floor, gravity causes the ridge to push on the lithosphere that lies farther from the ridge.

GEOLOGIC FOLD

A region of curved or deformed stratified rocks.

DIKE

A relatively narrow tabular (broad and flat) discordant body, often nearly vertical; A small linear shaped pluton; A slab of volcanic rock formed when pressure forces magma either upward and through fault cracks, thus enlarging the cracks, or sideways across/between older rock layers; technically it is any geologic body which cuts across flat rock structures, such as bedding, or massive rock formations.

LITHOSPHERE

A rigid layer made up of the uppermost part of the mantle and the crust. Tectonic activity occurs in this layer.

MOHS HARDNESS SCALE

A scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals.

MERCALLI SCALE

A scale that rates earthquakes according to their intensity and how much damage they cause at a particular place; the same earthquake can have different ratings because it causes different amounts of ground motion at different locations; 12 steps: 1-3 people notice vibrations, 4-6 slight damage, 7-9 moderate to heavy damage with some buildings jolted off foundations or destroyed, 10-12 great destruction, cracks appear in ground, waves seen on surface; This scale provides a correlation of observable damage to approximate intensity;

MOMENT MAGNITUDE SCALE

A scale that rates earthquakes by estimating the total energy released by an earthquake; Commonly used today; Can be used to rate earthquakes of all sizes at any distance; to rate an earthquake using this scale, geologists first study data from seismographs, which shows them the type and strength of the seismic waves produced. Geologists then use this information to infer how much movement occurred along the fault and the strength of the rocks that broke when the fault slipped.

ROCK CYCLE

A series of processes on Earth's surface & in the crust & mantle that slowly change rocks from one kind to another. Plate tectonics & the water cycle are it's driving forces.

ASEISMIC RIDGE

A series of volcanoes (underwater or above the surface) formed by the movement of the plates over a hot spot. They usually form a dogleg pattern, showing the change of direction in the plate's movement.

LACCOLITH

A sheet intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the formation of dome or mushroom-like form with a generally planar base; A dome of mushroom shaped pluton, much smaller than a batholith; A concordant body with a roughly flat base and convex top, usually with a feeder pipe below.

SILL

A slab of volcanic rock formed when magma squeezes between layers of rock; a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock; A relatively tabular (broad and flat) concordant body intruded along bedding planes.

LAMINAE

A small scale sequence of fine layers (thickness of less than 1 cm) that occurs in sedimentary rocks. They are normally smaller and less pronounced than bedding.

STOCK

A smaller irregular discordant igneous intrusion having a surface exposure of less than 40 square miles, differing from batholiths only in being smaller. Most are probably the cupolas of hidden batholiths.

GRADED BEDDING

A stratification profile in which a systematic change in grain size from the base of the bed to the top exist, usually with larger, coarser sediments at the base, which grade upward into progressively finer ones.

ORIENTED OVERGROWTH

A type of crystal aggregate that is formed by parallel deposits of one mineral on the surface of another. The surface atoms of the host mineral exert organizational forces on the atoms of the overgrowing crystal, orienting the latter's nuclei into the same crystal structure as the former's.

STRIKE-SLIP FAULT

A type of fault in which rocks on either side move past each other sideways with little up or down motion; Caused by shearing in the Earth's crust; Associated with transform boundaries; Example: San Andreas Fault

REVERSE FAULT

A type of fault where the hanging wall slide up over the footwall; Caused by compression in the Earth's crust; Associated with convergent plate boundaries; Example: northern Rocky Mountains.

NORMAL FAULT

A type of fault where the hanging wall slides downwards; Caused by tension in the Earth's crust; Associated with divergent plate boundaries; Example: Rio Grande rift valley in NM.

THRUST FAULT

A type of reverse fault when the dip is less than 45 degrees; Fault in which rocks of lower stratigraphic position (older) are pushed up and over higher strata (younger).

ORGANIC / BIOGENIC / BIOCLASTIC ROCKS

A type of sedimentary rock formed from the remains of organisms (usually those living in a marine environment). Limestone is the most abundant type of this sedimentary rock, making up coral reefs (which are formed of fossils, corals, and algae). Another example is coal, which is formed from cemented plant remains. When these rocks form in a marine environment, the temperature of the water dictates the type of bioclastic collections: cold = deep water = silica and warmer = shallow water = calcium carbonate.

VOLCANIC PIPE

A vertical conduit below a volcano through which magma has passed and that has become filled with solidified magma, volcanic breccia, and fragments of older rock; A tubular roughly vertical body that may have been a feeder vent for a volcano.

CONTINENTAL DRIFT

Alfred Wegener's hypothesis that the continents slowly move over Earth's surface as a result of convection currents in the mantle caused by Earth's rotation.

LOVE WAVES

Also called Q waves; Surface seismic waves that cause horizontal shifting of the Earth during and earthquake; These surface waves move slightly faster than Rayleigh waves and cause horizontal shearing of the Earth's crust.

NON-FOLIATED

Also called massive. Formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions (confining pressure). The original minerals within the rock recrystallize into larger sizes and the atoms become more tightly packed together, increasing the density of the rock. These types of rocks are identified on the basis of their composition, for example quartzite is composed of the mineral quartz and is metamorphosed sandstone and marble is composed of the mineral calcite and is metamorphosed limestone.

SECONDARY (S) WAVES

Also called transverse waves; Seismic waves that vibrate from side to side as well as up and down, shaking the ground back and forth; Waves that originate from an earthquake's focus; slower than p-waves; cannot move through liquids, only solids; Also called shake waves; shorter than p-waves, and is thus second to reach the seismometer;

PETROGENESIS

Also known as petrogeny, a branch of petrology dealing with the origin of igneous rocks. This rock identification technique is more favorable than petrography.

ANAEROBIC

An absence of free oxygen.

HOT SPOT

An area where material from deep within the mantle rises and then melts, forming magma. A volcano forms above one when magma erupts through the crust and reaches the surface; An offshoot of a convection cell that burns through the lithospheric material in the middle, not at the edges, of a plate.

PEDIPLAIN

An extensive plain formed in a desert by the coalescence of neighboring pediments.

CHONOLITH

An irregularly-shaped igneous intrusion with a demonstrable base, which is absent in other types of irregularly shaped intrusions (batholiths, stocks, bosses).

RAYLEIGH WAVES

An undulating (moving with a smooth wave-like motion) surface wave that travels over the surface of a solid, especially of the ground in an earthquake, with a speed independent of wavelength, the motion of the particles being in ellipses. These waves perpetuate ground roll during earthquakes.

PLANTATION

Any low-relief plain cutting across varied rocks and structures. Among the most common landscapes on Earth, planation surfaces include pediments, pediplains, etchplains, and peneplains. There has been much scientific controversy over the origins of such surfaces.

FOSSIL

Any trace of an ancient organism that has been preserved in rock.

DESCRIBE A CONTINENTAL/CONTINENTAL CONVERGENT BOUNDARY

Both edges are too light to subduct, thus one will override the other, causing uplift of material.

SANDSTONES

Clastic rocks formed from particles with diameters of .0625 mm to 2 mm. The identity of the cementing materials determines the strength of different varieties.

SHALE

Clastic rocks formed from silt and clay grains with diameters less than .0625 mm. These rocks make up almost half of all sedimentary rocks.

SIAL

Continental crust; 10-15 km thick; more complex and locally variable than the oceanic crust; consists of two layers separated by a seismic velocity discontinuity located 8-10 km below the surface: the upper layer and the lower layer.

LUSTER

Describes how light is reflected from a mineral's surface. Described as metallic (galena), submetallic/dull (graphite), glassy (quartz, topaz), earthy (hematite), waxy/ greasy/pearly (talc). This property depends on the type of atomic bonds present in the mineral & thus demonstrates characteristics about the mineral's structure & texture.

COLOR

Easily observed, but rarely useful as an identification method.

SPECIFIC GRAVITY

Expresses how much more dense a mineral is than water. It is usually defined as the weight of a volume of a mineral divided by the weight of an equal volume of water in its densest state (4 degrees C).

FLOODPLAIN

Flat areas adjacent to rivers over which water flows during flooding. Each floods deposits a new layer of sediments here.

ALLUVIAL FAN

Form when a rapidly flowing river or stream carrying sediment abruptly reaches a basin, quickly depositing sediments that spread out in the shape of a fan on the basin floor.

DENDRITE

Formed from a single nucleus & with a single crystallographic orientation, these crystalline masses have a branching or treelike structure.

SEA-FLOOR SPREADING

Harry Hess's hypothesis; The sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added resulting in the conveyor belt-like movement of the ocean floor and ultimately the movement of the continents.

MANTLE DRAG FRICTION

Hot mantle that spreads out laterally beneath the ridges or at hot spots may speed up or slow down plate movement. Friction based.

MESOSPHERE / LOWER MANTLE

Hot, semi-solid rock layer that spans from the lower part of the mantle to the mantle-core boundary.

TRACE FOSSILS

Impressions left in rock by the movement of an organism, such as footprints.

TRENCH SUCTION FRICTION

Involves a downward frictional pull on oceanic plates in subduction zones due to convection currents.

LAVA

Magma that has reached Earth's surface. As this substance cools and solidifies, minerals arise in combinations based upon their respective densities.

EVAPORITES

Minerals or rocks created through the evaporation of the liquid in a solution. Ions precipitate from the solution and form crystalline mineral residues. Example: Halite

DESCRIBE HOW EARTHQUAKES FORM

Most earthquakes begin in the lithosphere within 100 km of Earth's surface.

OCEAN RIDGES

Mountains formed at divergent boundaries beneath the ocean when plates move apart allowing molten material from the mantle to rise up and create long mountain chains.

VOLCANIC MOUNTAINS

Mountains that form from the accumulation of products of volcanic eruptions.

FAULT BLOCK MOUNTAINS

Occurs when two normal faults cut through a block of rock; Form when two normal faults occur parallel to one another, leaving a block of exposed rock between them. As the hanging wall of each slips downward, the block in between moved upward. Example: Great Basin

SIMA

Oceanic crust; 5-10 km thick; remarkably uniform in composition and thickness and consists of a layer of sediments that overlies three distinct layers of igneous rock.

ANHEDRAL CRYSTALS

Produced by rapid cooling, these crystals have internal regularity but no external crystal faces; lacks all trace of ideal crystal morphology.

EUHEDRAL CRYSTALS

Produced by slower cooling processes, these crystals have well-formed crystal faces & ideal crystal morphology.

SUBHEDRAL CRYSTALS

Produced by slower cooling processes, these crystals lack crystal faces, but ideal crystal morphology is recognizable.

CONCHOIDAL FRACTURE

Refers to a shell-like pattern of fracture, characterized by a series of concentric rings spreading outward from the point of the break.

REGIONAL METAMORPHISM

Refers to metamorphism that is produced by the tectonic movement (drift) of continental plates. Continental drift exerts enormous pressure at the edges of the plates (where they abut), forcing rocks into a semi-plastic state as their atoms break their bonds. Pressure causes the rocks to bend or fold without breaking. Refers to a large band of metamorphic activity; this occurs over large areas and generally does not show any relationship to igneous bodies, and instead is associated with areas of high orogenic activity. The rocks created by this metamorphic activity are usually highly deformed and strongly foliated, such as slate, schists, and gneiss. An example is The Appalachian Mountains which have abundant metamorphic material because they are the result of three past collisions between the NA and African Plates.

CONTACT METAMORPHISM

Refers to metamorphism that occurs when country rock comes into contact with high-heat igneous intrusions. It occurs in rocks adjacent to igneous instructions as the result of the high temperatures associated with the intrusion. This type of metamorphism is restricted to the small area surrounding the intrusion that has been heated by the magma, thus the closer to the heat source (magma chamber) the more metamorphism. The rocks created by this metamorphic activity are usually fine-grained and non-foliated.

OROGENESIS

Refers to mountain building processes, specifically as they relate to the movement of tectonic plates.

CRYSTAL HABIT

Refers to the favored crystal growth pattern of a mineral species; The shape of the mineral--some minerals possess distinctive shapes.

EPEIROGENIC UPLIFT

Refers to upheavals or depressions of land exhibiting long wavelengths and little folding apart from broad undulations.

AEROBIC

Relating to, involving, or requiring free oxygen.

MONOCLINE

Rock structures that slope in one direction only and often pass into geologic fault lines.

INTRUSIVE IGNEOUS ROCK

Rock that formed slowly when magma hardens beneath Earth's surface, forming large, coarse-grained crystals. Granite, the most abundant type of this rock, makes up the continental crust. Also called plutonic igneous rock. These rocks never reach Earth's surface during the cooling process, and instead are exposed after millions of years of weathering.

CLASTIC SEDIMENTARY ROCKS

Rocks formed exclusively from fragments of other rocks. Because these fragments vary greatly in composition, analysis of their size is more useful for identification. The sizes provide information about the type of medium used for transportation and its energy. Composed of lithified sediments which have undergone compaction or cementation. Examples: conglomerate, breccia and sandstone, which are all formed by cementation and shale, which is formed by compaction.

PRECIPITATED / CHEMICAL / NON-CLASTIC SEDIMENTARY ROCKS

Sedimentary rocks formed from the by-products of chemical reactions; Precipitated out of a solution in a very slow, drip by drip, process.

CARBONATE ROCKS

Sedimentary rocks made up of carbonate compounds, usually calcite or dolomite. These rocks react with acid. Calcite often forms due to temperature changes in seawater, which causes precipitation. Examples: Limestone, which is composed of calcite or aragonite, and dolostone, which is composed of the mineral dolomite.

VARVE

Sediments (common in glacier fed lakes) characterized by the repetition of two layers: a lower layer of coarse silt and an upper layer of fine-grained silt and clay, each deposited seasonally.

PRIMARY (P) WAVES

Seismic waves that compress and expand the ground like an accordion; Waves that originate from an earthquake's focus; fastest moving seismic wave and thus the first to reach the seismometers; cause the crust to vibrate forward and back along the path of the wave, compressing material as it moves through it; can travel through any material, but move fastest through solids; sometimes called push-pull waves or compression waves;

CONCRETIONS

Solid bodies of near-spherical shape that are sometimes found in sedimentary rock. They are formed when a cementing material forms around a nucleus, such as a shell fragment. The cement binds all the particles together and enlarges the object like a snowball.

FOCUS

The area beneath Earth's surface where rock that is under stress breaks, triggering an earthquake;

FOOTWALL

The block of rock that forms the lower half of a fault.

HANGING WALL

The block of rock that forms the upper half of a fault.

MOHOROVICIC DISCONTINUITY / MOHO

The boundary between Earth's crust and mantle.

DIAGENESIS

The change of sediments or existing sedimentary rocks into a different sedimentary rock during and after rock formation (lithification), at temperatures and pressures less than that required for the formation of metamorphic rocks. It does not include weathering.

DESCRIBE A OCEANIC/CONTINENTAL CONVERGENT BOUNDARY

The colliding plates produce effects relatively similar to oceanic/oceanic collisions, but the difference in density between the materials involved causes the oceanic plate to subduct under the continental plate. Subduction forces the continental materials upward, creating a line of onshore volcanic mountains along the subduction zone.

STREAK

The color of a mineral when powdered & observed against an unglazed white porcelain plate. While the actual color of different samples of a mineral may vary, this quality is consistent. This color is often different from the mineral's actual color. Example: Pyrite, which has a golden color, produces a greenish black streak.

SPIRAL GROWTH / SCREW DISLOCATION

The continuous growth of a single crystalline layer in the form of a spiral. Occurs quickly & in regions of low saturation.

FLEXURE

The folding or bending of strata under compression.

WHAT CAUSES EARTHQUAKES?

The forces of plate movement, which are driven by convection currents in the mantle. Plate movements produce stress in Earth's crust, adding energy to rock and forming faults. Stress increases along a fault until the rock breaks. As energy is released from the breaking rock, an earthquake occurs.

WHAT CAUSES EARTH'S CRUST TO BEND, STRETCH, BREAK, UPLIFT, TILT, FOLD, AND SLIDE?

The forces produced by the slow movement of Earth's plates.

TWO-DIMENSIONAL NUCLEATION

The ideal type of crystal growth; In this process crystals are formed in separate layers. Crystal faces are built up through accumulation of these layers, as the mineral's atoms arrange themselves in the configuration of the highest stability. This process occurs slowly & requires high supersaturation.

MANTLE

The layer of hot, solid material between Earth's crust and core. This layer is made up of rocks such as peridotite and eclogite with temperatures varying from 100-3,500 degrees C.

REGOLITH

The layer of unconsolidated rocky material covering bedrock.

STRATIFICATION

The layering of sediments to form sedimentary rocks. It occurs due to variations in the volume, mineral composition, or color of sediment in transport, and the energy of the transporting medium.

DESCRIBE AN OCEANIC/OCEANIC DIVERGENT BOUNDARY

The materials involved are composed of heavy and dense, but very thin, dark colored oceanic lithospheric material, usually basalt. As magma rises, the ocean floor begins to dome upward. The upward pressure eventually forces an underwater rip in the center of the dome and the magma erupts. The erupted materials cool rapidly and build upward, forming MID-OCEAN RIDGES, which are fairly common and found all over the globe. The ocean floor is constantly being pushed apart at these boundaries, causing sea-floor spreading, which results in the creation of huge oceanic plates.

DESCRIBE A CONTINENTAL/CONTINENTAL DIVERGENT BOUNDARY

The materials involved are composed of less dense, but very thick, lighter colored continental lithospheric material, usually granite. As magma rises, the crust begins to dome upward. The upward pressure eventually forces an rip in the center of the dome and the magma erupts. The erupted materials eventually cool and forms a RIFT VALLEY between the adjoining volcanic peaks.

SEDIMENTS

The materials that make up sedimentary rocks. They are deposited in layers through erosion.

INTENSITY

The measure of observable effect in terms of damage and destruction caused by an earthquake.

CRYSTALLINE STRUCTURE

The most efficient arrangement of atoms that form a crystal shape. It is the key defining factor in identifying minerals.

WHAT CAUSES PLATE TECTONIC MOVEMENT?

The motion induced in the lithosphere by the rise and fall of convection cell material in the asthenosphere.

PROTOLITHS

The original, unmetamorphosed rock from which a given metamorphic rock is formed.

CONVERGENT BOUNDARY / DESTRUCTIVE BOUNDARY

The place where two plates collide together, or converge; Creates mountain ranges, subduction zones, and trenches.

DIVERGENT BOUNDARY / CONSTRUCTIVE BOUNDARY

The place where two plates move apart, or diverge; Creates oceanic ridges and rift valleys.

TRANSFORM BOUNDARY / CONSERVATIVE BOUNDARY

The place where two plates slip past each other, moving in opposite directions but crust is neither created nor destroyed; Creates earthquakes. Also called a strike-slip fault. May be found in any location where plates abut.

EPICENTER

The point on Earth's surface directly above the focus.

PORE-FLUID PRESSURE

The pressure created by the release of volatiles due to thermal energy.

LITHOSTATIC, OR CONFINING, PRESSURE

The pressure or stress imposed on a layer of soil or rock by the weight of overlying material.

LITHIFICATION

The process by which sediments compact under pressure, expel connate fluids, & gradually consolidate into solid rock.

PERMINERALIZATION

The process of fossilization whereby mineral deposits (such as Calcium Phosphate or Silica) intrude the pore space of an organism's skeleton forming internal casts of the organism within its organic tissue.

NUCLEATION

The process whereby clusters of atoms in a liquid arrange themselves in a solid configuration. When this process occurs slowly, large, stable crystals form; when this process occurs quickly many unstable, small crystals form but will eventually aggregate into a large, solid crystal.

SLAB-PULL GRAVITY

The pulling force exerted by a cold, dense oceanic plate plunging (subducting) into the mantle at trenches due to its own weight.

BRANCHING GROWTH

The rapid growth of a crystal in limited directions, resulting in a tree-like structure. Heat transfer halts favorable growth & causes growth in a unfavorable direction.

SEISMOGRAM

The record of an earthquake's seismic waves produced by a seismograph;

MAGNITUDE

The relative measure of how big an earthquake is; How much energy is released during an earthquake.

VISCOSITY

The resistance of a liquid to flow.

OROGENIC UPLIFT

The result of tectonic-plate collisions and results in mountain ranges or a more modest uplift over a large region. The most extreme form of this type of uplift is a continental-continental crustal collision. In this process, two continents are sutured together and large mountain ranges are produced. The collision of the Indian and Eurasian plates is a good example of the extent to which orogenic uplift can reach. Heavy thrust faulting (of the Indian plate beneath the Eurasian plate) and folding are responsible for the suturing together of the two plates. The collision of the Indian and Eurasian plates not only produced the Himalaya, but is also responsible for crustal thickening north into Siberia.

ISOSTATIC UPLIFT

The rise in the level of land relative to the sea that is caused by the massive removal of weight from a particular area by erosion or ice-sheet retreat.

POST-GLACIAL REBOUND

The rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Uplift in theses areas occurs as temperatures rise, removing the weight of the ice-sheets through melting and allowing land masses to rise significantly.

ISOSTATIC DEPRESSION

The sinking of large parts of the Earth's crust into the asthenosphere. The sinking is caused by a heavy weight placed on the Earth's surface. Often this is caused by the heavy weight of glacial ice due to continental glaciation.

ASTHENOSPHERE

The soft, topmost layer of the mantle on which the lithosphere floats. A combination of heat & pressure keep this layer's composite material plastic.

CRUST

The solid rock outermost layer of Earth that includes both dry land & ocean floor. This layer is composed mainly of basalt and granite and is less dense, cooler, and more rigid than the planet's internal layers.

PALEONTOLOGY

The study of ancient plant & animal life. The bulk of information on this subject is provided by the fossil record. Contributes to an understanding of the ways that environmental & geological factors affected evolution.

PETROLOGY

The study of how rocks are formed.

FRACTURE

The way a mineral looks when it breaks apart in an irregular way. Different ways of classifying it are: shell-shaped (quartz), hackly (metals), earthy (clay), and uneven (rough and irregular). Exhibited by minerals with imperfect or nonexistent cleavage.

DESCRIBE AN OCEANIC/OCEANIC CONVERGENT BOUNDARY

These plates are forced together by the spreading of the ocean floor. Tremendous frictional forces are created as the plates collide and some of the oceanic material builds upward, while other oceanic material bends downward. The leading edges of the boundaries meet around 700 km downward. The forces involved push some material upward through the lithosphere to become a volcano. The built up materials may eventually break the ocean surface to become volcanic islands. This volcanism is explosive and the quick release of strain and pressure cause devastating deep focus earthquakes. Although some material is pushed upward, other oceanic material bends downward forming deep trenches and the leading edge of this plate will subduct back into the asthenosphere.

FOLDED MOUNTAINS

This type of mountain often forms chains at convergent plate boundaries from the long-term deformation and metamorphism of sedimentary and igneous rocks.

UPLIFT

Vertical elevation of the Earth's surface in response to natural causes. Broad, relatively slow and gentle uplift is termed warping, or epeirogeny, in contrast to the more concentrated and severe orogeny, the uplift associated with earthquakes and mountain building.

SEISMIC WAVES

Vibrations that travel through Earth carrying the energy released during an earthquake; originate at the focus and carry energy away from it through Earth's interior, and across the surface.

SURFACE WAVES

Waves that travel above the Earth's surface. These waves move more slowly than body waves, and because of their low frequencies they produce more destruction than body waves. These waves cause so much damage by causing the ground to roll and move like ocean waves; Because these waves more so slowly, it takes them longer to pass a location, thus the intense undulating (wavelike) ground motion creates the greatest amount of damage in an earthquake; Occur when some s- and/or p-waves reach Earth's surface at the epicenter;

DISCORDANT

When referring to plutonic bodies, indicates a differing type of rock cutting across country rock strata or formation. Examples: batholiths, stock.

CONCORDANT / CONFORMABLE

When referring to plutonic bodies, indicates that the intruding magma of sills and laccoliths lies parallel to, rather than cutting across, country strata. Examples: lopolith, phacolith, sill, laccolith.

ETCHPLAIN

Where deep weathering occurs on a landscape, a dichotomy (contrast) is set up between the thick regolith of weak, weathered rock and the underlying zone of intact rock. If subsequent erosion removes the weathered regolith, then a new planation surface develops through exposure of the old weathering front. This process often results in the exposure of structurally defined compartments of resistant rock. A subsurface landscape is essentially etched from the rock by deep weathering and subsequent removal of weathered products.

DESCRIBE THE IMPORTANCE OF WIND IN CONTINENTAL SEDIMENT DEPOSITION

Wind can carry airborne sediments across land and deposit them elsewhere. Wind is most effective in regions with little stabilizing vegetation and plentiful sand. Example: well sorted sand dunes.