Earth System Science Vocabularies Part III:
Earth System Environments

Earth Structure

inner core
The center part of the earth's core, extending from a depth of about 5100 km to the center (6371 km) of the earth; is probably solid
outer core
The outer or upper zone of the earth's core, extending from a depth of 2900 km to 5100 km; it is presumed to be liquid
The zone of the earth below the crust and above the core; hypothesized to be largely of peridotitic composition
oceanic crust
The type of the earth's crust which underlies the ocean basins; is about 5-10 km thick; largely basaltic in composition
continental crust
The type of the Earth's crust which underlies the continents and the continental shelves; ranges in thickness from about 25-70 km; largely of granitic composition senso lato
The solid portion of the Earth, in plate tectonics, a layer of strength relative to the underlying asthenosphere for deformation at geologic rates; includes the crust and part of the upper mantle and is on the order of 100 km in thickness
The layer or shell of the earth below the lithosphere which is weak and in which isostatic adjustments take place, magmas may be generated and seismic waves are strongly attenuated; part of the upper mantle

Atmospheric Structure

Extends to altitudes of 10-16 km extending from the earth's surface in which temperature generally decreases rapidly with altitude, clouds form, and convection is active
The layer of the atmosphere extending from 10 to 50 km, overlying the troposphere; contains the protective ozone layer which protects the biosphere from harmful ultraviolet radiation; characterized by a region of constant temperature for the first several km; between 20 and 50 km the temperature increases with height reaching a temperature maximum at the stratopause
The region in which temperature again decreases with increasing altitude, reaching a minimum at about 85 km.
Extends out to about 500 km; is a region of increasing temperature

Physiographic Provinces


continental shelf
That part of the continental margin that is between the shoreline and the continental slope; characterized by its very gentle slope of .1o
continental rise
That part of a continental margin that is between the continental slope and the abyssal plain, common to trailing edges and uncommon on leading edges. It is a gentle incline with slopes of 1:40 to 1:2000, and generally smooth topography although it may bear submarine canyons
continental slope
That part of the continental margin that is between the continental shelf and the continental rise if there is one. It is characterized by its relatively steep slope of 3-6o
abyssal plain
A flat region of the ocean floor, usually at the base of a continental rise, whose slope is less than 1:1000. It is formed by deposition of gravity-current and pelagic sediments that obscure the preexisting topography
mid ocean ridge
A continuous, seismic, median mountain range extending through the North and South Atlantic Oceans, the Indian Ocean, and the South Pacific Ocean. It is a broad, fractured swell with a central rift valley and usually extremely rugged topography; it is 1-3 km in height and about 1500 km in width and over 84,0000 km in length
oceanic islands
Island either composed of basalt or of biogenic origin (e.g. coral reef, etc.) as distinguished from islands having rocks characteristic of continents
A coral reef appearing in plan view as a ring or horseshoe-shaped reef, rising from deep water of the open sea, they typically form around volcanic islands which have subsided
coral reef
A coral (+/-algal) organic reef; a mound or ridge of in-place coral colonies and accumulated skeletal fragments
An elevation of the sea floor, 1000 meters or higher, either flat-topped (called a guyot) or peaked. Seamounts may be either discrete, arranged in a linear or random grouping, or connected at their base and aligned along a ridge or rise
oceanic plateaus
A broad, more or less flat-topped and ill-defined elevation of the sea floor, generally over 200 meters in height
passive margin (trailing edge)
A continental margin formed by rifting and continental rupture; characterized by broad continental shelves and located within plates rather than at the leading edge of a plate
active margin (convergent plate boundary)
Marking the boundary between two plates that are moving toward each other; the leading edge of a tectonic plate
ocean basin
The area of the sea floor between the base of the continental margin, usually the foot of the continental rise, and the mid-ocean ridge
A narrow, elongate depression of the deep-sea floor associated with a subduction zone. Oriented parallel to a volcanic arc and commonly to the edge of the continent
island arc
An offshore volcanic arc; generally a curved linear belt of volcanoes above a subduction zone


trailing edge coast
A coastal area that is not the site of subduction or plate collision but is located in the interior of a lithospheric plate; characterized by gentle slopes and low energywaves
leading edge coast
A coastal area that is the site of convergent or transform plate motion; associated with uplift, and a steep coastline cut by high energy waves
The seaward end of the widened funnel shaped tidal mouth of a river valley where fresh water comes into contact with seawater and where tidal effects are evident
The low, nearly flat, triangular or fan-shaped alluvial tract of land at or near the mouth of a river, often crossed by many distributaries of the main river, perhaps extending beyond the general trend of the coast
coastal plain
A flat area of low elevation, smooth and level or gently undulating land underlain by sedimentary rock having few or no prominent surface irregularities parallel to a coast
Lying or formed at the base of a mountain or mountain range; in the United States-a plateau underlain by crystalline rock extending from New Jersey to Alabama and lying east of the Appalachian Mountains


Any part of the Earth's crust sufficiently elevated above the surrounding land surface of which it forms a part, typically with steep sides considerable bare rock surfaces and a restricted summit area
volcanic mountains
Formed by deposition of volcanic rocks and not be deformation of preexisting rock; found on land and seafloor (e.g. Hawaiian Islands), island arcs (e.g. Aleutian Islands); continental arcs (e.g. Cascade Range)
fold and thrust mountains (compressional)
Resulting from compressional deformation, faulting and folding; crustal shortening occurs by slip on sub-parallel thrust or high-angle reverse faults
fault-block mountains (extensional)
Mountains formed by extensional processes that form horsts and grabens (e.g. Basin and Range) by normal faulting
basin and range
Topography, landscape or physiographic province characterized by a series of tilted fault blocks forming longitudinal, asymmetric ridges or mountains and broad, intervening basins
A depressed area with no surface outlet; a low area in the earth's crust of tectonic origin in which sediments have accumulated
rift valley
A valley that has developed along a rift where stretching of the lithosphere has occurred; the deep central cleft in the crest of the mid-ocean ridge

Continental Interior

interior (intracratonic) basin (e.g. Michigan, Wyoming basin)
A depression entirely surrounded by higher land and from which no stream flows outward to the ocean
shield or craton
Part of the Earth's continental crust that has attained stability and has been little deformed for a prolonged period; mostly Precambrian in age
greenstone belt
Term applied to elongate or belt-like areas within Precambrian shields that are characterized by abundant greenstone; includes volcano-sedimentary piles, with a general trend from mafic to felsic volcanics
high-grade terrane, or granite-gneiss belt
Term applied to Precambrian (usually Archean) terranes that have experienced granulite or upper amphibolite facies metamorphism, extensive penetrative deformation, and usually accompanied by intrusion of syn- or post-kinematic granitoids
Any flat area of great extent and elevation, considerably elevated above the adjacent country or sea level; may be tectonic (e.g. isostatic uplift of the Colorado Plateau), residual or volcanic (e.g. Columbia Plateau) in origin
Any flat area at low elevation
An extensive, treeless grassland area in the semiarid mid latitudes of southeastern Europe and Asia; typically located in interior portions of continents in the Northern Hemisphere

USGS Physical Divisions of the United States; Divisions, Provinces, (Sections)

Appalachian Highlands
Adirondack Province, Appalachian Plateaus Province (Allgeheny Mountains, Catskills, Cumberland Mountains, Kanawha, Mohawk, Southern New York), Blue Ridge Province (northern, southern), New England Province (Green Mountain, New England Upland, Seaboard Lowland, Taconic, White Mountain), Piedmont Province (Piedmont Lowlands, Piedmont Upland), St. Lawrence Valley Province (Champlain), Valley and Ridge Province (Hudson Valley, Middle, Tennessee)
Atlantic Plain
Coastal Plane Province (East Gulf Coastal, Embayed, Floridian, Mississippi Alluvial, Sea Island, West Gulf Coastal Plains)
Interior Highlands
Ouchita Province (Arkansas Valley, Ouachita Mountains) and Ozark Plateaus Province (Boston "Mountains", Springfield-Salem)
Interior Plains
Central Lowland Province (Dissected Till, Eastern Lake, Osage Plains, Till Plains, Western Lake, Wisconsin Driftless), Great Plains Province (Black Hills, Central Texas, Colorado Piedmont, Edwards Plateau, High Plains, Missouri Plateau, Pecos Valley, Plains Border, Raton), and Interior Low Plateaus Province (Highland Rim, Lexington Plain, Nashville Basin)
Intermontane Plateaus
Basin and Range Province (Great Basin, Mexican Highland, Sacramento, Salton Trough, Sonoran Desert), Colorado Plateaus Province (Canyon Lands, Datil, Grand Canyon, High Plateaus of Utah, Navajo, Uinta Basin), Columbia Plateaus Province (Blue Mountain, Harney, Payette, Snake River Plain, Walla Walla Plateau)
Laurentian Upland
Superior Upland Province
Pacific Mountain System
Cascade-Sierra Mountains Province (Middle Cascade, Northern Cascade, Sierra Nevada Mountains), Lower Californian Province, Pacific Border Province (California Coast, California Trough, Klamath Mountains, Los Angeles Ranges, Olympic Mountains, Oregon Coast Range, Puget Trough)
Rocky Mountain System
Middle Rocky Mountains Province, Northern Rocky Mountains Province, Southern Rocky Mountains, Wyoming Basin

Climatologic Provinces

A climatic zone located in the polar latitudes, marked by conditions too harsh to support vegetation
Treeless plains that lie poleward of the tree line; the plants thereon are sedges, mosses, lichens and a few small shrubs; underlain by permafrost
The latitudinal zones that lie between 23.5 and 66.50 N or S respectively.
The zone of the Earth's surface between the Tropics of Cancer 23.5 N and Capricorn 23.5 S; any area of the earth with tropical conditions
mid-latitude desert
A vast desert area occurring within latitudes 30-50o north or south of the Equator in the interior of a large continental mass
rain shadow deserts
Found on the lee-side of mountain ranges (e.g. east of the Sierra Nevada Mountains)
interior desert
Found in continental interiors far from sources of moisture (e.g. Gobi and Takla Makan deserts of Central Asia)
coastal desert
Any desert bordering an ocean with an offshore cold current; also known as west-coast desert
polar desert
Areas of low precipitation in polar regions due to sinking of cold dry air
savannah (seasonal)
A tropical or sub-tropical region of grassland and other drought-resistant vegetation; having a long dry season but with a pronounced wet season and continuously high temperatures
Characterized by mild, wet winters and warm to hot, dry summers; typically occurs on the west side of continents between about 30 and 45o latitude
A climate that is characterized by large annual temperature variations and sufficient moisture to support abundant plant life
A locale with a climate characterized by insufficient moisture to support appreciable plant life
A climax community that characterizes a particular natural region, especially a particular type of vegetation, climatically bounded, which dominates a large geographic area


A region with a mean annual precipitation of 10 inches or less; typically devoid of vegetation
mid-latitude desert
A vast desert area occurring within latitudes 30-50o north or south of the Equator in the interior of a large continental mass
rain shadow deserts
found on the lee-side of mountain ranges (e.g. east of the Sierra Nevada Mountains)
interior desert
found in continental interiors far from sources of moisture (e.g. Gobi and Takla Makan deserts of Central Asia)
coastal desert
Any desert bordering an ocean; also known as west-coast desert
polar desert
Areas of low precipitation in polar regions due to sinking of cold dry air


Biological communities that are dominated by trees and other woody vegetation
tropical rain forest
Occur near the equator, bounded by latitudes 23.5o N and S; great diversity of species; temperature on average is 20-25oC, annual rainfall exceeding 2000 mm, soil is nutrient poor and acidic, typically with a multi-layered canopy
temperate forests
Well-defined seasons with distinct winter; growing season of 140-200 days, 4-6 months frost free; temperature varies from 30 to +30oC; 75-150 cm annual precipitation
deciduous forests
Plants that shed their leaves annually
coniferous forest
Gymnosperm plants, having needle-like or scale-like leaves and bearing cones that bear seeds
boreal (taiga)
Occurs between 50 and 60o north latitude; seasons are divided into short, moist and moderately warm summers and long, cold and dry winters; growing season is <130 days; temperatures are very low, precipitation is mostly in the form of snow 40-100 cm annually


Lands dominated by grasses rather than large shrubs or trees
savannah (tropical grasslands)
Grassland with scattered individual trees; warm or hot climate with a distinct wet and dry season; where annual rainfall is from 50-127 cm/year and is concentrated in 6-8 months followed by a long period of drought when fires can occur
temperate grasslands (also pampas of Argentina; steppes of Russia; plans and prairies of central North America)
Distinct seasons that vary from hot summer to cold winter (-40 to +38oC), and moderate rainfall (50-90 cm/year)


Extremely cold climate, low biotic diversity, simple vegetation structure, limited drainage, continuous to discontinuous permafrost, short growing season
In northern hemisphere encircling the north pole, cold desert-like conditions; growing season ranges from 50-60 days; winter temperature is 34oC with summers as high as 3-12oC; precipitation is 15-25 cm/year; soil is permafrost
Located on mountains throughout the world at high altitude where trees can't grow

Aquatic Freshwater

Containing low salt concentration, usually less than 1%
lakes and ponds
Bodies of freshwater ranging from a few square meters to thousands of square kilometers
streams and rivers
Bodies of flowing water, confined to a channel(s) moving in one direction
Areas of standing water that support aquatic plants; marshes, swamps, and bogs

Aquatic Marine

Covers about 75% of Earth's surface; large bodies of saline waters
intertidal (littoral) zone
Where the ocean meets the land; sometimes it is submerged and at other times exposed as waves and tides come in and out; may be vertically stratified on rocky coasts, less stratified on sandy shores; between high and low water
pelagic zone
Waters farther from land, open ocean; marine organisms whose environment is the open ocean, rather than the bottom or shore areas
benthic zone
Below the pelagic zone, pertaining to the substrate or organisms living on or in the substrate
abyssal zone
Deep ocean, very cold water; pertaining to the ocean environment or depth zone of between 3500 and 6000 meters; including the organisms of that environment
oceanic vent communities
Ecosystems that have developed at hydrothermal vent areas (e.g. along segments of the mid-ocean ridge); these systems are typically dependent on chemosynthesis for energy to sustain the system; home to thermophilic bacteria and tube worms


Environments (or State) of Human Habitation

Relating to the latest period of the Stone Age characterized by polished stone implements
Relating to the earliest period of the Stone Age when chipped stone tools were first used
A way of life that is deeply embedded in the demands of agricultural production
nomadic or pastoral
Subsistence activity that involves the breeding and herding of animals to satisfy the human needs of food, shelter, and clothing
hearth areas
Geographic settings where new cultural practices such as agriculture, language, and religion have developed, and from which they have subsequently spread (e.g. the Fertile Crescent)
Relating to life in a city
An outlying part of a city or town, surrounding the urban core
A central city and adjacent counties or cities with functional connections to the central city
Characteristic of the country, suggests open land and farming
More Developed Country (MDC; or Developed Country)
A country that has demonstrated progress in development as measured by economic, social (education, health) and demographic indicators of development, e.g. Human Development Index (created by the United Nations)
Less Developed Country (LDC; or Developing Country)
A country in early stages of progress towards development as measured by economic, social (education, health) and demographic indicators of development, e.g. Human Development Index (created by the United Nations)

Scale of Human Habitation

community or neighborhood
People living near one another; a section lived in by neighbors and usually having distinguishing characteristics; people with common interests living in a particular area
urban system
An interdependent set of urban settlements (towns and cities) within a specified region
county (or parish)
The largest territorial division for local government within a state of the United States
state or province
One of the constituent units of a nation having a federal government
region (of country)
A collective identity based on a population's politico-territorial identification within a state or across state boundaries
nation or country
A group of people often sharing common elements of culture such as religion, language, or a history of political identity; and possessing a more or less organized government and territory, characterized by a relatively large size and independent status
supranational organization
A collection of individual states with a common goal that may be economic and/or political in nature (e.g. the European Union, OPEC)