Florida Geological Survey - Geology Topics
Glossary of Geologic Terms
Other glossary resources
- having no definite shape or boundaries; a term applied to
rocks and minerals that have no definite crystalline
- Archaic Period - 8,000 BC - 500 BC, the
period after which paleoindian people settled into permanent
residence in Florida.
- a water-saturated zone of rock below the Earth's surface
capable of producing water in useful quantities, as from a
- objects made by humans, such as stone tools; studied by
- a dark-colored, fine-grained, igneous rock formed from
molten rock that flowed onto the Earth's surface.
- basement rocks or basement - refers to
very deep, ancient rocks that underlie the continents and
- a large area of lower elevation than surrounding areas.
- marine invertebrate animals in which the soft parts are
enclosed by two shells, called valves.
- tiny marine animals that build colonies with their shells.
- containing or primarily made of the mineral calcite (calcium
- Cenozoic Era - the latest of the four
eras into which geologic time, as recorded by the stratified
rocks of the Earth's crust, is divided; it extends from the
end of the Mesozoic Era to and including the present, or
- consisting of fragments of rocks or organic structures:
gravels, sands, silts, and clays.
- confined aquifer - a zone of subsurface
water-bearing rocks that contain water under pressure due to
zones above and below it having low permeability, which
restrict the flow of water into and out of it. An artesian
aquifer is a type of confined aquifer.
- soft, porous limestone composed of broken shells, corals,
and other organic debris.
- small, colonial, bottom-dwelling, marine animals that
secrete external skeletons of calcium carbonate (calcite).
The colonies they create with their skeletons can make
enormous reef-complexes, such as the Florida Keys, the
Australian Great Barrier Reef, and many coral islands in the
Pacific Ocean, and other oceans.
- a marine animal consisting of a cup or "head" containing the
vital organs, numerous radiating arms, an elongate, jointed
stem, and a root-like attachment to the sea bottom while the
body, stem and arms float.
- CaMg(CO3)2, a rock-forming, carbonate mineral, very common
- a term for a sedimentary rock composed of fragmental,
concretionary, or precipitated dolomite of organic or
- one of a group of invertebrate marine animals, many of which
have spines; popularly called "sand dollars, sea biscuits,
or sea urchins."
- a community of organisms, including humans, interacting with
one another and the environment in which they live.
- all of the external factors that may act on an organism,
either plant or animal, or on a natural community. For
example: gravity, air, wind, sunlight, moisture,
temperature, soil, and other organisms are some of the
environmental factors that may affect the life processes of
- a large division of geological time consisting of two or
more geological periods.
- the natural processes of weathering, disintegration,
dissolving, and removal and transportation of rock and earth
material, mainly by water and wind, as well as by ice.
- exotic terrain - a terrain that has
undergone significant motion or travel with respect to the
stable continent to which it is accreted. Florida could be
considered an exotic terrain with respect to the North
American continent, because it is thought to have once been
part of northwestern Africa.
- a break in the Earth's rocks along which there has been
displacement of the rocks. Displacement may vary from inches
- land next to a stream or river that is flooded during
- small, one-celled, mostly marine animals which secrete
shells of calcium carbonate or build them of cemented sand
grains. They range in size from microscopic to a few
centimeters across. They occur in such quantities that their
fossil shells make up almost all of certain limestone rocks
in Florida and other places in the world.
- a rock unit possessing distinctive characteristics, such as
mineral content, fossils, or color, that allows it to be
distinguished from adjacent rock units.
- remains or traces of prehistoric animals or plants. The most
common types consist of bones, carbon films, shells, molds,
casts, and petrified wood.
- fuller's earth - a type of clay that is
commercially valuable and widely used as cat litter and as a
dispersant in insecticides.
- the study of the planet Earth, the materials of which it is
made, processes that affect these materials, the changes
that the Earth has undergone in the past and the changes it
is currently undergoing.
- the branch of geology which deals with the form of the
Earth, the configuration of its surface, and the changes
that take place in land forms over time.
- a large body of ice with definite lateral limits, which
moves in a downslope direction due to its great mass, as in
- a light-colored, coarse-grained, igneous rock formed from
magma that cooled below Earth's surface.
- a shore-protection structure that projects away from shore,
usually made of rocks, wood pilings, or sheet metal.
- heavy minerals - a suite of accessory
minerals of a sedimentary rock or sediments having specific
gravities greater than 2.9. The most common heavy minerals
found in Florida are: rutile, ilmenite, leucoxene,
staurolite, zircon, kyanite, sillimanite, tourmaline,
spinel, topaz, corundum, and monazite.
- a type of terrain characterized by sinkholes, caves,
disappearing streams, springs, rolling topography, and
underground drainage systems. Such terrain is created by
ground-water dissolving limestone.
- a rock composed essentially of clay minerals of the
kaolinite group, most commonly kaolinite. High purity
deposits of this mineral are valuable for making quality
- a method of waste disposal wherein materials are buried.
Present environmental protection laws require the burial
sites to be constructed with impermeable barriers, such as
clay or plastic liners, to prevent hazardous wastes or
pollutants from escaping to the surrounding soils or air.
- molten rock that flows onto the surface from a volcano or
- a bedded sedimentary deposit consisting chiefly of calcium
carbonate. Limestone is an important and widely distributed
of the carbonate rocks; it is the consolidated equivalent of
limy mud, calcareous sand, or shell fragments.
- to turn to rock. Several geological processes can operate to
consolidate loose sediments into hard rocks. Pressure from
thick sequences of overlying sediments can cause
lithification; for example, loose sand turned into
sandstone. Chemical changes caused by ground water can
cement loose sediments into hard rocks; for example, loose
sea shells and sand cemented into coquina limestone.
- molten rock generated within the Earth.
- a metal (Mg), which, when chemically combined with calcium
carbonate, Ca(CO3), forms the mineral dolomite, CaMg(CO3)2.
- refers to sea water, to sediments deposited in sea water, or
to animals that live in the sea, as opposed to fresh water.
- a heavy, silver-white, metallic element, the only metal that
is liquid at room temperature; also called quicksilver. A
virulent poison, dangerous to handle and work with.
- invertebrate animals, including a variety of marine, fresh
water and terrestrial snails; clams, oysters, mussels,
scallops; squids, octopus, pearly nautilus, as well as the
many extinct varieties.
- archeological term referring to native American cultures
prior to 8,000 BC; prehistoric inhabitants of Florida.
- the science that deals with the life of past geological
ages, based on the study of fossils.
- a dark brown or black, organic residuum produced by the
partial decomposition and disintegration of mosses, trees,
and other plants that grow in marshes or other wet places.
Peat deposits form when the rate of accumulation of plant
matter exceeds the rate of destruction by weathering or
organisms. One of the largest peat deposits in the world is
in the Everglades.
- movement of water through the pores or voids in rock or
- one unit of geological time into which Earth history is
divided. A period is a subdivision of an era.
- a measure of a porous material's ability to allow fluids or
gases to flow through its pores. An important property of
rocks that determines how much and how rapidly fluids or
gases can move through them; for example, how much water can
be pumped from an aquifer (see: porosity).
- phosphate rock - a sedimentary rock
containing calcium phosphate. Florida has some of the most
extensive deposits of phosphate rocks in the world. Very
important in the manufacturing of fertilizer.
- plate tectonics - a theory that large
"plates" of the Earth's colder, upper crustal rocks are
capable of moving slowly (like rafts) on top of deeper,
hotter, and more fluid rocks in the mantle. Geologists have
identified seven large plates and 11 or more smaller ones on
the Earth's surface.
- Pleistocene Epoch - the earlier of the
two epochs comprising the Quaternary period.
- a measure of the amount of voids (pores) in a material. An
important property of rocks that determines the quantities
of fluids or gases they can store; for example, the amount
of water an aquifer can store (see: permeability).
- potable water - water that can be
consumed by humans without ill effects. Government agencies
have adopted standards of quality that specify limits of
chemical constituents in water sources.
- potentiometric surface - an imaginary
surface defined by the level to which water in an aquifer
would rise in a well due to the natural pressure in the
- 1. the process whereby solids are left behind when liquids
evaporate; for example, vast deposits of salt were created
when ancient seas evaporated. 2. precipitates: the solid
materials, themselves. (see: precipitation)
- 1. hydrology: water discharged from the atmosphere
in the form of fog, rain, snow, sleet, or hail. 2.
chemistry: the process of separating different minerals from
a solution by evaporation; for example, salt from sea water.
- an invisible, odorless, tasteless, radioactive gas that is
formed when uranium-238 decays. It can accumulate in
buildings, causing potential health hazards.
- the act or process of restoring mined-out lands to a useful
state. Also, the industry devoted to the recovery or re-use
of waste materials.
- rift or rifting - refers to the breaking
apart of continental plates.
- salty; sea water or water nearly as salty as sea water.
- a type of sedimentary rock made of sand grains cemented
- an escarpment, cliff, or steep slope along the margin of a
plateau, mesa, or terrace.
- pertaining to vibrations in the Earth, such as earthquakes;
or to equipment or methods used to create Earth vibrations,
such as exploding dynamite in oil exploration.
- a type of sedimentary rock made of clay particles cemented
together and which usually can be made to split into thin
slabs (see: slate).
- an underwater area covered by shallow water which may
- pertaining to clastic, non-carbonate rocks that are almost
exclusively silicon-bearing, either as forms of quartz or as
clays. Examples of Florida siliclastics are loose quartz
sands, silts, or clays.
- a sedimentary rock made of silt-size particles cemented
- a depression in the land surface, usually round or
funnel-shaped, that connects with a subterranean passage
created by solution of limestone rocks by circulating ground
water. Sinkholes may also form by collapse of a cavern roof.
- a type of metamorphic rock created from shale, and is
usually harder than shale.
- solution feature - a topographic or
geomorphic feature of a landscape that was formed as a
result of water dissolving rocks, usually limestone or
dolostone, such as: sinkholes, caves, disappearing streams,
springs, and sinkhole lakes.
- spreading center - a fissure separating
continental plates, created when the plates move apart.
- the branch of geology that studies the formation,
composition, sequence, and correlation of the layered
rock-sequences that make up the Earth's crust.
- structural geology - the branch of
geology concerned with the deformation of rock bodies and
with interpreting the natural forces that caused the
- the geologic process whereby one continental plate slides
under another and is gradually consumed in the Earth's
- a line or mark of splitting open or of joining together,
such as where parts of two continental masses collide and
- a shallow depression in the land's surface which may be
filled with water. In karst terrain it may indicate an
incipient sinkhole forming.
- pertaining to the rock structures and external forms
resulting from the deformation of the Earth's crust.
- a hard covering or supporting structure of some invertebrate
animals; a shell.
- a property of an aquifer which defines the rate at which
water moves through it.
- part of the life process of plants by which water vapor
escapes from leaves and enters the atmosphere.
- ancient arthropods having a hard outer skeleton, and which
became extinct over 200 million years ago.
- in reference to aquifers, it describes a condition whereby
water-bearing rocks are at atmospheric pressure, i.e., water
- a surface of erosion or non-deposition that separates
younger strata from older rocks. It represents a missing
span of time from the rock record.
- refers to animals that have a backbone.
- vug- A cavity, void or large pore in a rock that is
commonly lined with mineral precipitates.
- vuggy-see vug above.
- water table - in an aquifer, it is the
upper surface of the zone of saturation under unconfined
conditions; water in the rocks is at atmospheric pressure.