Geologic Landforms Flashcards
Volcanoes that have steep sides and a symmetrical cone
Stratovolcano
Associated magma is often viscous, making these volcanoes’ eruptions highly explosives
Stratovolcano
Volcanoes that produced low viscosity, runny lava that spreads far from the source, forming gentle slopes
Shield Volcano
Also called as Scoria Cones
Cinder Volcano
These are single, steep with straight or gently concave sides, and with a crater at the top
Cinder Volcano
Mixed landforms consisting of related volcanic centers and their associated lava flows and pyroclastic rock that may form due to changes in eruptive habit or in the location of the principal vent area on a particular volcano
Complex Volcano
A volcanic caldera that has been partially filled by a new central cone
Somma Volcano
Deep-sea hydrothermal vents where volcanic activities released dark colored smoke
Black Smokers
Roughly circular holes where a volcanic origin is postulated, but where no igneous rock can be found and may have only been formed from gaseous eruptions
Cryptovolcano
Forms due to the collapse of the summit of a large composite volcano following an explosive eruption
Caldera
Known as explosion craters, these are shallow craters that were caused by volcanic eruptions
Maar
Forms from piling of lava around the vent due to viscous magma being erupted effusively onto the surface
Lava Dome
A basaltic lava flow that has a fissured, rough, clinkery or jagged surface
Aa Lava
A lava flow that has a surface flow structure that looks like coiled rope or cord due to relatively low viscosity
Pahoehoe Lava
Spheroidal-shaped solidified lava formed underwater when the magma rapidly cooled as it made contact with the cold seawater
Pillow Lava
Elongated, pillar-like columns that formed from the cooling of lava, causing shrinkage fractures
Columnar Joints
A large quantity of molten lava in a crater, vent or other depression in the ground
Lava Lake
Volcanic vents or “stream valves” which emit volatile gasses such as hydrochloric acid, sulfur dioxide and ammonium chloride - at high temperatures in powerful jets
Fumaroles
Volcanic vents similar to fumaroles but lack sulfur dioxide emissions
Solfatara
Thick ice mass that forms over hundreds or thousands of years that originated on land from the accumulation, compaction and recrystallization of snow
Glacier
Formations where valley glaciers leave mountains and spread on to a flat land as large lobes of spreading ice
Piedmont
Drifting floating masses of ice which broke off from ice shelves
Icebergs
Glacial ice covering high upland areas
Ice Caps
U-shaped feature created during glaciation when narrow valleys undergo a transformation as the glacier widens and deepens them
Glacial Trough
Large valley glacier systems which consist of numerous cirques and smaller valley glaciers that feed ice into large trunk glacier
Hanging Valley
A ridge that descends towards a valley floor or coastline from a higher elevation, that ends in an inverted-V face produced by erosional truncation of the spur by the action of either streams, waves or glaciers
Truncated Spur
A small bowl- or amphitheater-shaped depression, where it is the focal point of the glacier’s growth, because it is the area of snow accumulation and ice formation
Cirque
Thin, crest of rock left after two adjacent glaciers have worn a steep ridge into the rock
Arete
Accumulation of dirt and rocks that have fallen onto the glacier surface or have been pushed along by the glacier as it moves
Moraine
Deep, often spectacular, steep-sided inlets of the sea that are present at high latitudes where mountains are adjacent to the ocean
Fjord
Rock outcrops that have been partially or completely covered by ice caps due to topography
Nunataks
A valley or depression in the land bordered by fault zones and separating tectonic plates
Rift Valley
Asymmetric ridges, steep on one side and gentle on the other, that form by the erosion of gently dipping rock beds
Cuestas
Triangular facets with their bases parallel to the strike and apices or peaks, pointing up the dip of the rock
Flatirons
Relatively level, large expanse of land that rises some 1,500 feet (457 meters) or more above its surroundings and has at least one steep side
Plateau
Capped-areas with resistant, near horizontal layer is uplifted or forms from erosion attacks to form either a more or less straight front created by parallel retreat, or an irregular front with erosion scraps resulting from spring erosion or concentration of surface runoff
Mesa
Flat-topped, steep-sided towers of rock
Butte
Created through the process of erosion, the gradual wearing away of earth by water, wind and ice
Butte
Dip-slip fault in which the hanging wall has move down relative to the foot wall
Normal Fault
Dip-slip fault where the hanging wall moves upward relative to the footwall
Reverse fault
Faults where bodies slide against one another
Strike-slip fault
A block that moved downward between subparallel normal faults dipping towards each other
Graben
Blocks that remain high bounded by two subparallel normal faults dipping towards each other
Horst
A series of rock formations that are exposed above the ground, usually forming a line of narrow crests or ridges on top with a series of hills or mountains
Hogbacks
Bends or wraps of rocks caused by compressive stress
Folds
An arch-shaped fold formed from compressional stress
Anticline
A trough-shaped fold formed from compressional stress
Syncline
Craters that formed due to meteorite impacts
Meteor Crater
Natural Subterranean runway voids; may be simple in plan or have complex ramifications; may extend vertically or horizontally, and it may occupy one or more levels that forms due to the dissolution of carbonate rocks
Cave
Large, flat plain of karst territory
Polje
Etched, pitted, grooved, fluted and otherwise rugged surface formed from weathered limestone
Lapies
Residual hills are steep-sided or vertical and separated from each other by swamps or alluvial plains
Tower Karst
A karst landscape where the terrain is approximately equally shared by conical dolines and conical residual hills
Cone Karst
Valleys where a surface drainage pattern first develops on a non-soluble rock and later erodes into soluble rock when subsurface drainage totally defeats the surface flow
Karst Valley
Closed cone- or bowl-shaped hollows of small or moderate depressions that forms from carbonate rocks
Doline
Large-scale dolines
Uvalas
Depression that varies in depth from a mere indentation of a few feet to a maximum of 100 feet or more and forms where the rock below the land surface is limestone, carbonate rock, salt beds or rocks that can naturally be dissolved by groundwater circulating through them
Sinkholes
Most rapidly changing land forms which can be identified on a single photograph by tone, texture, pattern and shape
Coast
A shoreline formation that meets a body of water and contains sand, gravel, soil or particles of sediment from seashells and other sea life
Beach
A shallow body of water protected from a larger body of water (usually the ocean) by sandbars, barrier islands, or coral reefs
Lagoon
Large isolated inland bodies of water that forms due to water filling large depressions
Lake
A deposition bar or beach landform off coasts or lake shores
Spit
A bar that extends outward from the shore, connecting with an island
Tombolo
Extend outwards from the shoreline in a triangular shape that forms through accretion and progradation of sand and shingle
Cuspate Foreland
A long, thin, sandy stretch of land, oriented parallel to the mainland coast that protects the coast from the full force of powerful storm waves
Barrier island
Discrete shoreline protuberances formed where rivers enter oceans, seas, lakes or lagoons and supply sediment more rapidly than it can be redistributed
Delta
Formed as coastal forests where mangrove trees can grow
Swamps
Coastal wetlands that form when mud is deposited by tides or rivers
Mudflat
Fine-grained rocks that shrunk due to desiccation
Mudcracks
Forms from action of waves to unconsolidated sediment
Ripples
Forms when wave erosion has hollowed out a line of weakness in otherwise resistant promontory and two caves on opposite sides of a headland unite
Sea arch
Single column or columns of rock that jut toward the sky where they standout from the beach formations such as headlands or they may shoot out of the water, looking completely out of place
Sea Stack
Ring-shaped coral reef, island, or series of islets that surrounds a lagoon
Atoll
A reef that has either an entirely shallow backreef zone (lagoon) or none at all
Fringing Reef
Complex organogenic framework of corals and sponges which forms a rocky eminence on the sea floor and customarily grows upward to the tide limit
Coral Reef
Deformed beds that rolled into small anticlines and sharp synclines that formed from the disturbance off paleocurrents
Convoluted Beds
River that bend in a sinuous watercourse that forms when the moving water in a stream erodes the outer banks and widen its valley
Meandering River
A channel that consists of a network of small channels separated by small and often temporary islands called eyots
Braided River
A fluvial system consisting of a river, lagoon and barriers
Estuary
A narrow, deep, rocky and steep-walled valley carved by swift-moving river with a depth that may be considerably greater than its width
Canyon
U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake
Oxbow Lake
Develops when channel levee breaks and causes an overbank flooding
Crevasse Splay
Fan-shaped deposits that are fed by a channel emanating from a very narrow, steep valley in a region of high topographic relief
Alluvial Fan
Accumulation of adjacent alluvial fans
Bajada
Naturally between a river’s banks and the floodplain around it that blocks water
Levee
Stream channels with flat floors and steep walls of sediment usually found in deserts or other arid climates and completely dry up between periods of activity due to water-less conditions
Arroyo
Circular holes that were caused by erosion due to the downward circular motion of eroding particles
Potholes
Areas of great accumulation of sand found in arid and semi-arid regions
Deserts
Sand seas or areas where there is a high accumulation of sand
Ergs
Applied to wind-blown silts of different compositions
Loess
Areas where deep erosion of poorly consolidated rocks creates a landscape of steep slopes, sparse vegetation and intricate stream networks
Badlands
Crescentic concave ridges and mounds created and shaped by the transportation and deposition of sediment with the slip face transverse to the wind
Transverse Dune
Linear dunes that form from constant wind direction and with no vegetation
Seif / Longitudinal dunes
Isolated, long, scoop-shaped hollows, or parabolas, of sand with ends following the wind direction that forms due to sand blowouts and subsequent deposition
Barchan Dune
Dunes that form in coastal areas where there is a partial cover of vegetation, a strong onshore wind, and abundant sand with ends opposite that of barchan dunes
Parabolic Dune
Dunes with varying directions of ends that form from highly variable with direction
Star Dune
Deflations where the topsoil or sand has been carried away by the wind
Blowout
Intricately pitted rock surfaces that have often been attributed to wind abrasion
Honeycomb Stuctures
Alcoves and niches in rock walls that may have been resulted from wind abrasion, where they are at the base of a cliff
Wind Caves
Short, flat-topped sand ridges which extend parallel to the prevailing winds but lack the collapsing fronts
Undulations
Isolated rock islands formed due to its highly resistant nature
Inselberg
A streamlined, wind-sculpted landform that is carved in soft rock by persistent winds in flat deserts oriented parallel to the prevailing winds
Yardang
Residual masses of weak rock capped with harder rock primarily formed by the wind action
Pedestal Rock
Irregular shaped rock formation that is tall and pillar-like
Hoodoo
Rocks that exhibit one or polished and faceted surfaces, but these are relatively rare because strong winds, abundance of sand, and absence of vegetation are essential to their best development
Ventifact
