geology
Barrier Island
a long, relatively narrow island running parallel to the mainland-built up by the action of waves and currents and serving to protect the coast from erosion by surf and tidal surges.
Valley
an area of low land between hills or mountains
Plateau
an area of relatively level high ground.
Drainage Network
an array of interconnecting streams that together drain an area
Stalactite
an icicle-like structure that hangs from the ceiling of a cavern
mesa
an isolated flat-topped hill with steep sides, found in landscapes with horizontal strata.
Confined Aquifer
aquifer below the land surface that is saturated with water.
Unconfined Aquifer
aquifer in which there is no impermeable layer restricting the upper surface of the zone of saturation
Mass Extinctions
are episodes in which a large number of plant and animal species become extinct within a relatively short period of geologic time
Reverse Fault
are exactly the opposite of normal faults. If the hanging wall rises relative to the footwall
Gulley
deep and wide channel caused by running water erosion
Residence Time
defined as the amount of water in a reservoir divided by either the rate of addition of water to the reservoir or the rate of loss from it
Point Bar
deposit of sediment build up by a river on the inside bend of a meander
Shearing
describes a distinct motion of two rock surfaces against each other. It is most often caused by intense pressure under the earth's crust.
trellis drainage
develops in valley and ridge terrain, where rocks of varying resistance to erosion are folded into anticlines and synclines
Rectangular Drainage
develops on rocks that are of approximately uniform resistance to erosion, but which have two directions of jointing at approximately right angles or 90 degrees.
Relief
difference in elevation between any two points; local relief is the difference between adjacent points (e.g., a hill and a valley); total relief is the difference between the highest and lowest points on the map.
Normal Fault
dip-slip fault in which the block above the fault has moved downward relative to the block below
Strike
direction of the line formed by the intersection of a fault, bed, or other planar feature and a horizontal plane
Elevation
distance above sea level. Elevations are usually measured in meters or feet
Dendritic Drainage
drainage pattern that may develop on homogeneous rock, which has a shape resembling the pattern made by the branches of a tree or the veins of a leaf.
Coastline
dynamic, high energy, and geologically complicated places where many different erosional
Nonconformity
exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock
Overturned
fold, or overfold, has the axial plane inclined to such an extent that the strata on one limb
Aquiclude
formation which is impermeable to the flow of water.
Ripples
forms small waves
Sublimation
frequently occurs around volcanic vents where minerals such as sulfur, orpiment, realgar, and cinnabar are deposited.
Tributaries
freshwater stream that feeds into a larger stream or river
Hogbacks
is a long, narrow ridge or a series of hills with a narrow crest and steep slopes of nearly equal inclination on both flanks
Effluent Stream
is a river whose water originates from the groundwater beneath the surface, the local aquifer, and it increases in volume further downstream.
Contours
is an imaginary line connecting points of equal elevation( a contour) on a single surface, such as the top of a formation.
Aquifer
is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt)
Intergranular Porosity
is that that occurs between the grains of soil, sediment, or incompletely cemented sedimentary rock.
Wave Refraction
is the bending of a wave as it propagates over different depths.
Wave Length
is the distance between two adjacent points on the wave that have similar displacements
Outcrop
is the exposed rock, so named because the exposed rock
Porosity
is the percentage of void space in a rock.
Relative Age
rock is its age in comparison with other rocks
Bed Load
sand, pebbles, and boulders that are moved along the bed of a stream and that are too heavy to be carried in suspension
groundwater
water held underground in the soil or in pores and crevices in rock.
Fresh Water
water that contains insignificant amounts of salts, as in rivers and lakes
Runoff
water that flows over the ground surface rather than soaking into the ground
Potable Water
water that is safe to drink
Breakers
waves breaking into foam as they approach or dash against the shore
Fracture Porosity
A type of secondary porosity produced by the tectonic fracturing of rock. Fractures themselves typically do not have much volume, but by joining preexisting pores, they enhance permeability significantly. In exceedingly rare cases, nonreservoir rocks such as granite can become reservoir rocks if sufficient fracturing occurs.
Flood
A very heavy flow of water, which is greater than the normal flow of water and goes over the stream's normal channel.
Distributaries
A river channel branching out from the main river and not rejoining it.
Hurricane
A severe storm that develops over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low-pressure storm center
Rip Current
A strong, narrow current that flows briefly from the shore back toward the ocean through a narrow opening.
Hydraulic Gradient
The slope of the water table. It is determined by finding the height difference between two points on the water table and dividing by the horizontal distance between the two points.
Ductile
they may bend or fold, and the resulting structures are called folds
suspended load
The load contains small rocks and soil in suspension, which can make the river look muddy.
Mountains
is a large landform that rises above the surrounding land in a limited area, usually in the form of a peak
Basin
is a large low-lying area. It is often below sea level.
Recharge
primary method through which water enters an aquifer
Meander
(v.) to wander about, wind about; (n.) a sharp turn or twist
Vuggy Porosity
. Results from leaching of carbonate rock by circulating acidic waters.
Alluvial Fan
A fan-shaped deposit of sediment formed when a stream's slope is abruptly reduced
Rapids
A fast-flowing and turbulent part of the course of a river
Delta
A landform made of sediment that is deposited where a river flows into an ocean or lake
River
A large, flowing body of water that usually empties into a sea or ocean.
Drought
A long period of dry weather
Tidal Flats
A marshy or muddy area that is alternately covered and uncovered by the rise and fall of the tide.
Faunal Succession
A principle or law stating that fossil species succeed one another in a definite and recognizable order; in general, fossils in progressively older rock show increasingly greater differences from species living at present.
Artesian Well
A well in which water rises because of pressure within the aquifer
Discharge
An outflow of water from a stream, pipe, groundwater aquifer, or watershed; the opposite of recharge.
Precipitation
Any form of water that falls from clouds and reaches Earth's surface.
Flood plain
Flat land near the edges of rivers formed by mud and silt deposited by floods
Infiltration
Flow of water from the land surface into the subsurface.
Absolute Age
The age of a rock in years
Abrasion
The grinding away of rock by other rock particles carried in water, ice, or wind
Saltation
The movement of sand or other sediments by short jumps and bounces that is caused by wind or water
Half-Life
The time required for one-half of the radioactive (parent) isotopes in a sample to decay to radiogenic (daughter) isotopes
Influent Stream
Type of stream that is everywhere above the groundwater table and flows in direct response to precipitation. Water from the channel moves down to the water table, forming a recharge mound.
Artesian Flow
Water may even reach the ground surface if the natural pressure is high enough, in which case the well
Brittle
When a rock breaks
Longshore Current
When a wave reaches a beach or coastline, it releases a burst of energy that generates a current, which runs parallel to the shoreline
Stream
a channel along which water is continually flowing down a slope
Stalagmite
a conical mineral deposit formed on the floor of a cave by the dripping of mineral-rich water
Oxbow Lake
a crescent-shaped lake (often temporary) that is formed when a meander of a river is cut off from the main channel
Natural Levee
a deposit of sand or mud built up along, and sloping away from, either side of the flood plain of a river or stream
Dome
a feature in structural geology consisting of symmetrical anticlines that intersect each other at their respective apices
Divide
a high point or ridge that determines the direction rivers flow
cave
a large hole with the ability to fit A person
Wave Cut Terrace
a level surface formed by wave erosion of a rocky shoreline beneath the surf zone, which may be visible at low tide
Tropical Storm
a localized, very intense low-pressure wind system, forming over tropical oceans and with winds of hurricane force.
Rain Shadow
a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather
Superposition
a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
Perched Water Table
a quantity of groundwater that lies above the regional water table because an underlying lens of impermeable rock or sediment prevents the water from sinking down to the regional water table
Tropical Depression
a storm near the equator with winds moving in a circle at speeds of up to 38 miles per hour
Braided Stream
a stream consisting of numerous intertwining channels
Saturated Zone
a zone in which all the pores and rock fractures are filled with water
Cuestas
are the expression of extensive outcrops of gently dipping strata, typically sedimentary strata, that consist of alternating beds of weak or loosely cemented strata, i.e. shale, mudstone, and marl and hard, well-lithified strata, i.e. sandstone and limestone.
Disconformity
between parallel layers of sedimentary rocks which represents a period of erosion or non-deposition.
Joint
break (fracture) of natural origin in the continuity of either a layer or body of rock that lacks any visible or measurable movement parallel to the surface
Thrust Fault
break in the Earth's crust, across which older rocks are pushed above younger rocks.
Storm Surge
coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as tropical cyclones
spring tide
highest tidal range that occurs due to the alignment of Earth, the moon, and the sun
Dunes
hills of sand formed by the wind
sinkhole
hole that connects a cave to the surface
Angular Unconformity
in which younger flat rock layers were deposited over older tilted, eroded rock layers.
Subsidence
involves the settling or sinking of a body of rock or sediment.
Formation
is a body of rock having a consistent set of physical characteristics that distinguish it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region.
Unconformity
is a contact between two rock units in which the upper unit is usually much younger than the lower unit
Syncline
is a fold with younger layers closer to the center of the structure
Isostatic Rebound
is the rise of land masses that were depressed by the huge weight of ice sheets during the last ice age
Plunging
is the vertical angle between the horizontal plane and the axis or line of maximum elongation of a feature
Beach
landform along the coast of an ocean or sea. It usually consists of loose particles, which are often composed of rock, such as sand, gravel, shingle, pebbles, or cobblestones
Isotopic Dating
minerals in them, is based on the fact that we know the decay rates of certain unstable isotopes of elements and that these rates have been constant over geological time.
Spit
narrow coastal land formation that is tied to the coast at one end
Waterfalls
natural streams of water falling from a high place
Cone of Depression
occurs in an aquifer when groundwater is pumped from a well. In an unconfined aquifer (water table), this is an actual depression of the water levels
Vugs
open spaces created by dissolution of some material Ex: caves & caverns
Radial
patterns form around isolated mountains (such as volcanoes) or hills, and the individual streams typically have dendritic drainage patterns
Fault
planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movement.
remediation techniques
pump and treat bioremediation phytoremediation permeable reactive barriers chemical precipitation chemical oxidation monitoring well oil skimmers
Dip
refer to the orientation or attitude of a geologic feature
Compressional
refers to a set of stress directed toward the center of a rock mass.
Tensional
refers to a stress which stretches rocks in two opposite directions
Surf Zone
shallow, usually between 5 and 10 m (16 and 33 ft) deep; this causes the waves to be unstable
Fold
stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation
Original Horizontality
states that layers of sediment are originally deposited horizontally under the action of gravity. It is a relative dating technique.
Terraces
step like ledges cut into mountains to make land suitable for farming
Cross Cutting Relationships
that states that the geologic feature which cuts another is the younger of the two features. It is a relative dating technique in geology.
Relative Humidity
the amount of water vapor actually in the air, expressed as a percentage of the maximum amount of water vapor the air can hold at the same temperature.
Drainage Basin
the area from which a single stream or river and its tributaries drains all of the water
Topography
the arrangement of the natural and artificial physical features of an area.
Hanging Wall
the block of rock that lies above an inclined fault or an ore body.
Foot Wall
the block of rock that lies on the underside of an inclined fault or of a mineral deposit.
Stratigraphy
the branch of geology concerned with the order and relative position of strata and their relationship to the geological time scale.
Paleontology
the branch of science concerned with fossil animals and plants.
Shoreline
the line along which a large body of water meets the land.
Base Level
the lowest point to which a stream can erode its channel
Wave
the movement of energy through a body of water
Channel
the path that a stream follows
Unsaturated Zone
the portion of the subsurface above the groundwater table. The soil and rock in this zone contains air as well as water in its pores.
Permeability
the property of rocks that is an indication of the ability for fluids (gas or liquid) to flow through rocks
Tides
the regular rise and fall of the ocean's surface influenced by the moon's gravity pulling on earth
Bed
the smallest division of rock or deposit
Geomorphology
the study of the physical features of the surface of the earth and their relation to its geological structures.
Hydrology
the study of water and its effects on and in the earth and in the atmosphere
Neap Tide
the tide with the least difference between consecutive low and high tides
wave height
the vertical distance between the highest (crest) and lowest (trough) parts of a wave
Meteoric Water
the water derived from precipitation (snow and rain). This includes water from lakes, rivers, and icemelts, which all originate from precipitation indirectly
Flood Stage
the water level at which a river overflows its banks
Stratigraphic Succession
this law states that in a vertical succession of rocks a time sequence is formed with the oldest layers at the bottom with younger ones at the top.
Badland
type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded by wind and water. They are characterized by steep slopes, minimal vegetation, lack of a substantial regolith, and high drainage density. They can resemble malpaís, a terrain of volcanic rock.
Anticline
type of fold that is an arch-like shape and has its oldest beds at its core
Groundwater Table
upper level of an underground surface in which the soil or rocks are permanently saturated with water
Karst Topography
usually forms in regions of plentiful rainfall where bedrock consists of carbonate-rich rock, such as limestone, gypsum, or dolomite, that is easily dissolved.
Soultion valley
valley created by two or more sink holes
Strike-Slip Fault
vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally.
