Topography
surface configuration of the Earth. The form of the land or landforms.
Landform
an individual topographic feature of whatever size.
Geomorphology
the study of the characteristics, orgin and development of landforms
Relief
The difference in elevation between the highest and lowest points in an area. The vertical variation from a mountain top to a valley bottom.
Crustal rearrangement
Portions of the mantle circulate in convective currents that break the overlying crust into a mosaic of huge blocks known as Tectonic plates.The movement of the tectonic plates is crustal rearrangement.. 200 mil years ago, it is believed that there was on
Plate boundaries
There are 13 major plates and several smaller plates that have been identified. The crustal movements of these plates vary and are defined by the boundaries between them. The 3 boundaries between plates are convergent, divergent, and transform boundaries.
Convergent Boundaries
Zones where the plates converge toward each other. 3 variations exist:
Oceanic-Continental
Oceanic-Oceanic
Continental-Continental
Oceanic-Continental Convergence Boundaries
Zone where oceanic lithosphere dives below continental lithosphere. This is known as the process of SUBDUCTION (some believe that this subduction action is a driving force in plate movements.Landform features that occur: Mountain ranges formed on land (ex
Oceanic-Oceanic Convergence Boundaries
Zones where 2 oceanic plates converge.Normally, deep oceanic trenches are formed and a series of volcanoes form on the ocean floor. These types of volcanoes develop into a series of volcanic island arcs such as Aleutian and Mariana Islands. (Mariana trenc
Continental-Continental Convergence Boundaries
Zones where 2 continental plates collide. No subduction takes place in these zones because the continental material is too buoyant to subduct and extensive mountain ranges are built as the plates collide. (Himalayas-result of India crashing into asia- and
Divergence boundaries
Zones where 2 plates are moving away from each other because of magma upwelling from the mantle. Magma from the Asthensophere wells up in an opening betweeen plates and this flow of molten material produces a continuous line of active volcanoes that spill
Transform boundaries
Zones where 2 plates slip past one another laterally. Unlike convergent and divergent zones, tyhis lateral movement neither creates nor destroys crustal material.They create extensive fractures known as transform faults and these zones are charaterized by
Internal processes
Less extensive internal processes, Diastrophism & vulcanism, occur within tectonic plates and result in landform features that are less extensive from a geographic view in comparison to the plates themselves. The forces that create lanform features that c
Vulcanism
All phenomena connected to the orgin and movement of molten rock (magma) that originated below the Earth's crust.
Extrusive Vulcanism: Volcanism, when magma is expelled onto Earth's surface while still molten.
Intrusive Vulcanism: When magma is solidified
Extrusive Vulcanism
Commonly known as Volcanism, can produce an almost infinate variety of terrain features, the most common are: Lava flows/Shield volcanoes, cinder cones. composite volcanoes, calderas, and volcanic necks.
The magma that is extruded on Earth's surface is ca
Intrusive Vulcanism
Involves the solidification of magma within the Earth's crust. Some of these intrusions have a direct effect on topography as crustal material is raised. Many are far enough below surface to have no effect on topography. Common features are: batholiths, s
Diastrophism
General term that refers to the deformation of the Earth's crust. Term covers a variety of crustal movements in 2 catagories: Folding and Faulting. The process deals with solid rock. Rocks are bent and broken in a variety of ways in response to great pres
Folding
When crustal rocks are subjected to certain forces particularly lateral compression, they are often deformed by being bent in the process called folding. Can occur in any type of rock but it is most recognizable in sedimentary strata. Mostly takes place i
Faulting
Prominent feature of crustal stresses, the breaking apart of rock material.When rock is broken and is accompanying displacement (the actual movement of the crust on one or both sides of the break) the action is called faulting. Movement can be vertical, h
Rocks
The solid inorganic portion of the Earth known as the lithosphere. They are made up of solid cohesive aggregates of inorganic solid material and are chartacterized by a mix of minerals and grain sizes. 3 types: Igneous, sedimentary, and metamorphic.
A min
Igneous Rocks
ingi" latin for fire. Solidified hot molten lava (magma) that originated below the Earth's crust. Subduction of the sedimentary & metamorphic rock re-emerges as magma at great distances from the point of subduction and through solidification reforms into
Metamorphic Rocks
Form from the alteration of other types of rock mainly by the melting, contorting, and recrystallizing of other rocks (by heat and pressure). Deep in the ground tectonic forces squeeze, fold, heat and recrystallize solid rock. Under these conditions chemi
Sedimentary rocks
Formed when loose grains from other rocks are transported to new locations arelater consoldated. Sandstone is solidified from the layers of desposited sand. Limestone from compaction of the remains of marine organisms. Main characteristic is that they occ
Rock Cycles
The 3 rock types appear hard/permenant, but are a part of a cycle of formation and destruction.Igneous rocks are transformed by weathering and erosion into sedimentary rocks and into metmorphic rocks from heat and pressure. Sedimentary & metamorphic rocks
Distribution of rocks at/near Earth's surface
96% of crust Igneous and metamorphic. 4% is sedimentary. Whereas crust is primarily igneous, the portion of crust closest to and at the surface is sedimentary. Sedimentary rocks normally occurring in layers no thicker than 1.5 miles yet occupy 75% of expo
Denudation
An overall effect of disintegration, the weraing away and removal of rock by external forces. It involves 3 related external forces:
Weathering
Mass Wasting
Erosion
Weathering
Breaks down rocks into smaller components by atmospheric and biotic agents. Refers to a group of processes by which surface rock disintegrates into smaller particles or dissolve into water due to the impact of the atmosphere and hydrosphere. Weathering pr
Physical Weathering
Same as Mechanical. Physical disintegration of rock material without any changes to its chemical composition.Big rocks are mechanically weathered into small rocks by various stresses that cause the rock to fracture into smaller fragments. Most occurs at o
Chemical Weathering
Usually, but not always, accompanies mechanical weathering. It is the dec omposition of rock by the chemical alteration of its minerals. Almost all minerals are subject to alteration through atmospheric and biotic agents.Quartz is resistant to chemical ch
Biological Weathering
Plants frequntly and animals occasionally contribute to weathering. They invlove living organisms. Most noatable is the penetration of growing plat roots into cracks and crevices. Burrowing by animals mixes soil effectively and sometimes is a factor in ro
Mass wasting
Involves downslpoe movement of broken rock material due to gravity. It can take many forms, from a deadly mudflow rushing down the mountain to devestating landslides which deliver tons of debris down the mountain side in just seconds. More sublte forms ar
Erosion
Involves the extensive and generally more distantremoval of weathered rock material by external agents of running water (Fluvial processes), moving ice (Glaciation), coastal waters, wind (aeolian processes) and subsurface waters (in order of impotance). E
Fluvial Processes.
Involves running water and is the most important agent of erosion because it happens almost everywhere from precipitation. Encompasses overland flow (unchanneled downslope movement of surface water) and stream flow (channeled movement of water along a val
Glaciation
Moving ice. Have modified topography on many parts of the continents and the results are imprinted on terrain. Most of the glacial features that we observe today were formed during the Pleistocene epoch (ice age), a period from approx. 2 million yrs ago t
Coastal Water and related processes
Coastlines are shaped by agitated water crashing and lapping against them, with the result that coastal terrain is often quite different from the terrain of the shore just a short distance away. Coastal processes affect only a tiny fraction of the total a
Aeolian Processes
Wind action. Pronounced where ever fine-grained unconsolidated sedimentary material is exposed to atmosphere, without the protection of vegetation or moisture. Confined mainly to desert regions and along sandy beaches.The erosive force of the wind works t
Underground water
Can influence surface topography. Especially true in humid regions underlain by soluable rock such as limestone. Water beneath surface moves slowly through limestone structure and through chemical action dissolves the rock, creating erosion features such
Erosional features of Continental Glaciation
glacial valleys that become lakes, roche moutonnee, ice-scoured rocky knobs and scooped out depressions that become lakes of varying sizes. Major depositional features are: till plains, moraines, and drumlins.
Erosion features of Alpine Glaciation
aretes, horns, cirques( broad ampitheatre hollowed out at the head of a glacial valley), glacial troughs, and hanging valleys. Depositional features are terminal, lateral, and recessional medial moraines and tills.