Cumulative Geology Final Exam Flashcards

Terms Definitions
Asthenosphere
The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it.
Core
The central part of the Earth
Convergent Plate Boundary
A boundary between two plates that are moving toward each other.
Crust
The outer layer of rock, forming a thin skin over Earth's surface.
Divergent Plate Boundary
boundary between tectonic plates in which the two plates move away from each other, and new crust is created between them.
Hypothesis
Tentative explanations or solutions consistent with observed data.
Lithosphere
The solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle.
Mantle
The layer of hot, solid material between Earth's crust and core.
Theory
Rigously verified; as close as possible to what scientists accept as indisputable fact (proven).
Transformation Plate Boundary
Places where crustal plates shear laterally past one another. Crust is neither produced nor destroyed at this type of junction. Small to large earthquakes may occur.
Feldspar
Group of most common minerals of Earth's crust. All ... contain silicon, aluminum, and oxygen and may contain potassium, calcium, and sodium.
Ferromagnesian
Silicate mineral such as olivine, augite, hornblende, or biotite, in which iron and magnesium are essential chemical components.
Mineral
Solid homogeneous inorganic substances occurring in nature having a definite chemical composition -not created in lab.
Quartz
Colorless glass made of almost pure silica -SiO2
Aphanitic
(fine-grained) Rapid cooling at earth's surface results in tiny mineral crystals that can only be seen under a microscope.
Extrusive
Fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface.
Felsic
A ny light-colored igneous rock containing large abounts of Feldspar and Silica.
Intrusive
A type of ingneous rock that generally contains large crystals and forms when magma cools slowly beneath Earth's surface.
Mafic
Describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color.
Phaneritic
(coarse-grained)coarse-grained, crystals are large enough to be seen w/out a microscope, formed by slow cooling (intrusive).
Porphyry
A ny igneous rock with crystals embedded in a finer ground mass of minerals.
Cinder Cone
A steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening.
Composite Volcano
A tall, cone shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials.
Pyroclastic Debris
Fragments that are blown out of the volcano.
Shield Volcano
Broad, gently sloping cone constructed by solidified lava flow.
Chemical Weathering
The decomposition of rocks resulting from exposure to water and atmospheric gases. (oxygen, water, vapor, carbon dioxide) -actually changing the rock.
Erosion
The physical removal of rock by an agent such as running water, glacial ice, or wind.
Mechanical Weathering
The physical disintegration of rock into smaller pieces.
Soil
A layer of weathered unconsolidated material on top of bedrock; often also defined as containing organic matter and being capable of supporting plant growth. In mass wasting ... means unconsolidated material, regardless of particle size or composition.
Chert
A hard compact, fine-grained sedimentary rock formed almost entirely of silica. Composition-quartz Characteristics-Microcrystalline; very hard.
Clay
Sediment composed of particles with diameter less than 1/256 millimeter. Shale or mudstone comes out of this sediment.
Coal
A sedimentary rock formed from the consolidation of plant material. It is rich in carbon, usually black, and burns readily.
Limestone
A sedimentary rock composed mostly of calcite.
Rounding
The grinding away of sharp edges and corners of rock fragments during transportation.
Sand
Sediment composed of particles with a diameter between 1/16 and 2 millimeters.
Sandstone
A medium-grained sedimentary rock (between 1/16 and 2 millimeters) formed by the cementation of sand grains.
Sedimentary Rock
Rock that has formed from (1)lithification of any type of sediment (2)precipitation from solution, or (3)consolidation of the remains of plants or animals.
Shale
A fine-grained sedimentary rock (grains finer than1/16 millimeter in diameter) formed by the cementation of silt and clay (mud). ... has thin layers (laminations) and an ability to split (fissility) into small chips.
Silt
Sediment composed of particles with a diameter of 1/256 to 1/16 millimeter.
Sorting
Process of selection and separation of sediment grains according to their grain size (or grain shape or specific gravity).
Contact Metamorphism
Metamorphism in which temperature is the dominant factor. Occurs adjacent to magma bodies intruding cooler country rock. Produces nonfoliated rocks.
Foliation
Parallel alignment of textural and structural features of a rock.
Metamorphism
The transformation of preexisting rock into texturally or mineralogically distinct new rock as a result of high temperature, high pressure or both but without the rock melting in the process.
Nonfoliated
The texture of metamorphic rock in which the mineral grains are not arranged in planes or bands.
Regional Metamorphism
Metamorphic that takes place at considerable depth underground with plenty of pressure. Foliated rocks typically form here.
Cenozoic Era
The latest of the four eras into which geologic time is subdivided ; 65 million years ago to the present.
Mesozoic Era
The part of geologic time roughly 245-65 million years ago ; dinosaurs rose to prominence and became extinct.
Paleozoic Era
The part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant.
Pre-Cambrian Time
The largest span of time in the geologic time scale which covers the first 4 billion years, divided into three blocks of time called eras.
Creep
Very slow, continous down slope movement of soil or debris.
Earthflow
Slow-to-rapid mass wasting in which fine-grained soil moves downslope as a very viscous fluid.
Mass Wasting
Movement, caused by gravity, in which bedrock, rock debris, or soil moves downslope in bulk.
Mud Flow
A flowing mixture of debris and water, usually moving down a channel.
Rockfall
Rock falling freely or bouncing down a cliff.
Rockslide
Rapid sliding of a mass of bedrock along an inclined surface of weakness.
Base Level
A theoretical downward limit for stream erosion of Earth's surface.
Braided Stream
A stream that flows in a network of many interconnected rivulets around numerous bars.
Cut-off Meander
A new shorter channel across the narrow neck of a meander.
Dendritic Drainage
Drainage pattern of a river and its tributaries that resembles the branches of a tree or veins in a leaf. Rocks are folded and erosion has created a series of ridges of resistant rock and valleys of nonresistant rock. ex. southern Arkansas.
Downcutting
A valley-deepening process caused by erosion of streambed.
Flood Plain
A broad strip of land built up by sedimentation on either side of a stream channel.
Graident
A graded change in the magnitude of some physical quantity or dimension.
Lateral Erosion
Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
Meander
A pronounced sinuous curve along a stream's course.
Ox-bow Lake
A crecent-shaped lake occupying the abandoned channel of a stream meander that is isolated from the present channel by a meander cutoff and sedimentation.
Trellis Drainage
A pattern consisted of parallel main streams with short tributaries meeting them at right angles. Rocks are generally lying flat. ex. Oachita Mountains.
Aquifer
Body of saturated rock or sediment through which water can move easily (Phreatic Zone).
Cave
Naturally-formed underground chambers; solution features (typically in limestone bedrock), groundwater phenomenon.
Confined Aquifer
An aquifer completely filled with pressurized water and separated from the land suface by a realtively impermeable confining bed, such as shale.
Karst
An area with many sinkholes and a cave system beneath the land suface and usually lacking a suface stream.
Permeability
The capacity of a rock to transmit a fliud such as water or petroleum.
Phreatic Zone/Saturated Zone
Immediately above the impermeable material is a volume of rock or soil that is water-saturated, in which water fills all the accessible pore space.
Porosity
The percentage of a rock's volume that is taken up by openings.
Spring
A place where water flows naturally out of rock onto the land surface.
Unconfined Aquifer
A partially filled aquifer close to the land surface and marked by a rising and falling water table.
Vadose Zone/Unsaturated Zone
A subsurface zone in which rock openings are generally unsaturated and filled partially with water; above the saturated zone.
Water Table
The upper surface of the zone of saturation.
Alpine Glacier
Glaciation of mountainous area.
Continental Glacier
The covering of a large region of a continent by a sheet of glacial ice.
Firn
A compacted mass of granular snow, transitional between snow and glacier ice.
Glacier
A large long-lasting mass of ice, formed on land by the compaction and recrystallization of snow, which moves because of its own weight.
Glacial Ice
The mosaic of interlocking ice crystals that form a ...
U-shaped Valley
Characteristic cross-profile of a valley carved by a glacial erosion.
V-shaped Valley
Characteristic cross-profile of a valley carved by running water.
Barchan Dune
Where the sand supply is limited. A cresent-shaped dune with a steep slip face on the inward or concave side with the horns of the cresent pointing downwind.
Desert
A region with low precipitaion (usually defined as less than 25 cm (10") of precipitation per year).
Longitudinal Dune
(seif) Largest types of dune, symmetrical ridge of sand parallel to the wind direction.
Parabolic Dune
Deeply curved and is convex in the downwind direction with horns pointing upwind and are comonly anchored with vegetation.
Transverse Dune
A relatively straight, elongated dune oriented perpendicular to the wind direction.
Beach
Strip of sediment, usually sand but sometimes pebbles, boulders, or mud, that extends from the low-water line inland to a cliff or zone of permanent vegetation.
Beach Face
The section of the beach exposed to wave action.
Berm
Platform of wave-deposited sediment that is flat or slopes slightly landward.
Longshore Current
A moving mass of water that develops parallel to a shoreline.
Longshore Drift
Movement of sediment parallel to shore when waves strike a shoreline at an angle.
Anticline
A fold shaped like an arch in which the rock layers usually dip away from the axis of the fold and the oldest rocks are in the center of the fold.
Footwall
The undelyin surface on an inclined fault plane.
Hanging Wall
The overlying surface of an inclined fault plane.
Normal Fault
A fault in which the hanging-wall block moved down relative to the footwall block.
Reverse Fault
A fault in which the hanging-wall block moved up realtive to the footwall block.
Strike-Split
Fault A fault in which movement is parallel to the strike of the fault surface.
Syncline
A trough-like fold in which the rock layers usually dip toward an axis and the youngest rocks are in the center of the fold.
Thrust Fault
A reverse fault in which the ditp of the fault plane is at a low angle to horizontal.
Body Wave
Seismic wave that travels through Earth's interior.
Earthquake
A trembling or shaking of the ground caused by the sudden release of energy stored in the rocks beneath the surface.
Epicenter
The point on Earth's surface directly above the focus of an earthquake.
Focus
The point withing Earth from which seismic wave originate in an earthquake.
Intensity
A measurement of an earthquake's size by its effect on people and buildings.
Magnitude
A measurement of the energy released during an earthquake.
Modified Mercalli Scale
Scale expressing intesities of earthquakes (judged on amount of damage done) in Roman numerals ranging from I to XII.
P-Wave (primary wave)
A compressional wave (seismic wave) in which rock vibrates parallel to the direction of wave propagation.
Richter Scale
A numerical scale of earthquake magnitudes.
S-Wave (secondary wave)
A seismic propagated by a shearing motion, which causes rock to vibrate perpendicular to the direction of wave propagation.
Surface Wave
A seismic wave that travels on Earth's surface.
Abysal Plain
Very flat, sediment-covered region of the deep-sea floor, usually at the base of the continental rise.
Active Continental Margin
A margin consisting of a continental shelf, a continental slope and an oceanic trench.
Basalt
(Oceanic Crust) A fine-grained, mafic, igneous rock predominantly composed of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
Continental Shelf
A submarine platform at the edge of a continent, inclined very gently seaward generally at an angle of less than one degree.
Continental Slope
A relatively steep slope extending from a depth of 100 to 200 meters at the edge of the continental shelf down to oceanic depths.
Granite
(continental crust) A felsic, coarse-grained, igneous rock containing quartz and composed mostly of potassium- and sodium -rich feldspars.
Mid-Oceanic Ridge
A giant mountain range that lies under the ocean and extends around the world.
Oceanic Trench
A narrow, deep trough parallel to the edge of a continent or an island arc.
Passive Continental Margin
A margin that includes continental shelf, continental slope, and a continental rise that generally extends down to an abyssal plain at a depth of about 5 kilometers.
Seamounts
Conical mountain rising 1,000 meters or more above the sea floor.
Anthracite Coal
That has undergone low-grade metamorphism. Burns dust-free and smokeless.
Bituminous Coal
A mineral coal that contains volatile hydrocarbons and tarry matter and burns with a yellow, smoky flame; soft coal.
Lignite
A soft coal, usually dark brown, often having a distinct woodlike texture, and intermediate in density and carbon content between peat and bituminous coal.
Petroleum
Crude oil and natural gas. (Some geologists use this as a synonym for oil.)
Reserves
The discovered deposits of a geologic material that are economically and legally feasible to recover under present circumstances.
Resource
The total amount of a geologic material in all its deposits, discovered and undiscovered.
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