Earth’s Structure: Crust- outermost shell, 5km below ocean to 20km below land, >1% of volume and .4% mass, mono layer base of crust, significant change in
materials; Mantle- extends to 2900km, largest of floor shells, 84% volume and 67% mass, has lithosphere: hard, rigid layer-includes crust, asthenosphere:
200mi hot tar-like rocks, pliable, mesosphere: lower mantle, thick rigid rocks Outer Core- molten magma 5000km Inner Core- dens mass w/radius ~1450km,
made of iron/nickel or iron/silicate, magnetic field of E controlled by outer core, magnetic poles not same as axial poles; Composition: Minerals: naturally
formed compounds and elements of Earth, forms all rocks, more than 2000 known, fewer than 20 = 95% of composition of crustal rocks; Rock Cycle: new
igneous rock weathered and eroded creating sediments; sediments turned into sedimentary rock then weathered and eroded forming another generation of
sedimentary rock; at continental edges rock may be subducted and changed by heat and pressure producing metamorphic rock, some subducted material
completely melted and becomes new magma, forming new igneous rock; Major rock types: Igneous- solidification of magma, about 80% of crust, often
covered by sedimentary rocks: intrusive- form below surface, cools slowly, individual minerals can grow large, granite, gabbro; extrusive- form on surface
when magma forces its way up, cools rapidly=glassy, fine-grained surface, rhyolite, basalt; Metamorphic Rock- originally something else but formed by heat
and pressure working from within Earth, causes “cooking of rocks,” rearranges crystal structure of original rock, denser and less porous than sedimentary or
igneous, resistant to weathering- Types: Slate: from shale, Schist: from shale, basalt, Gneiss: from granite, Quartzbite: from sandstone, Marble: from limestone;
Sedimentary rocks- consolidation of sediment by pressure & cementation, most widespread, compacted into horizontal layers called strata, types based on grain
size and how formed: conglomerates- compacted gravel formed mechanically, cemented under pressure sandstone- compacted sand formed mechanically
limestone- chemically accumulated rock composed of calcium carbonate, coral and sea animals shale- cemented clay and silt formed mechanically coalorganically accumulated, compacted skeletal remains of organisms; topography: surface configuration of earth; landform: individual topographic feature of any
size; geomorphology: study of landforms; relief: difference in elevation between highest and lowest point; structure: nature arrangement and orientation of
landforms; Internal: surface disturbance prod. by earth’s internal thermal energy, constructive, uplifting, building forces that increase the relief of the land
surface: crustal rearrangements- crust is plastic; plate tectonics- theory of lithospheric plate movements; volcanism- mvt. of magma from interior of earth to
surface; diastrophism- deformation of the crust by folding and uplift (bending and breaking of crust); External: molding of peaks, slopes, valleys, and plains by
the work of gravity, water, wind, and ice: weathering- breaking up of rock in small components, physical and chemical; mass wasting- downslope movement of
broken material b/c of gravity; erosion- extensive and distinct removal of fragmented rock; Factors of Landform Development: 1) tectonic activity- intensity of
crustal motions produced by Earth’s internal energy 2) geologic structure- nature and arrangement of material 3) denudation- removal and deposition of rock
material via weathering and erosion 4) climate- temp. PPTN, humidity and wind all effect rates of erosion, deposition, weathering and types of drainage 5)
biota- vegetation, soils, organisms, humans can influence rates and type of landform development 6) time- vastness/magnitude, 4.6 bil. years old, processes are
very slow, dinosaurs- 160 mil. yrs., results are high magnitude
Theory: Pangaea broke up ~200 mil years ago, driving force is slow moving convection of heated material within the mantle, new ocean floor created at
midocean ridges by rising convection currents and volcanic activity, subduction: old lithosphere recycled back down into mantle near deep oceanic trenches
forms new crust; Divergent boundaries- plates move apart, new crust introduced, spreading within continent creates continental rift ie Great Rift Valley of East
Africa; Convergent boundaries- OP to CP: equals subduction, deep earthquakes, Andes along W. coast of S. America, deep oceanic trench with mountain
building and volcanic activity inland; OP on OP: equals subduction, deep earthquakes, deep ocean trench and chain of volcanic islands known as Island Arc,
Aleutian Islands, Alaska; CC on CC: no subduction, uplift of mountains results, volcanoes rare, shallow eq, Himalayas; Transform boundaries- slide past each
other, San Andreas Fault, CA, shallow earthquakes, does not create or destroy crust; Mantle plumes/hot spots- narrow plume of magma rising through plate,
under Hawaiian islands, as plates move away volcanoes become extinct; Volcanic Processes: lava- magma extruded on Earth surface; pyroclastic materiallava, rock fragments, ash, dust, erupts w/volcano, eruption styles- depends on chemistry of magma; most associated w/plate boundaries, Pacific “Ring of Fire”
prod. by subduction zones around margins of PO, 75% volcanoes occur there; EXTRUSIVE: Cinder Cones: small cone-shaped peak developed from ejected
pyroclastic material; Shield Volcanoes: quiet, fluid eruptions typical of volcanoes emitting basaltic lava, produce mountains with gentle sloping side (Hawaii);
Composite Volcanoes: explosive eruptions emitting more pyroclastic material and acidic lava, tall symmetrical mountains with steep sides, strato-volcanoes;
Lava Domes: develop from vicious lava that bulges up from a vent too thick to flow; Caldera: when volcano collapses or explodes creating a large basin
circular shaped depression, often fills w/water (Crater Lake Orgeon); Volcanic Necks: pipe or throat of an old volcano that filled w/solid lava; INTRUSIVE:
Batholith: core of mountain, intrusive uplift, imp in mtn building; Laccolith: slow moving lava force between horizontal layer of existing rocks, cause hills,
Black Hills of SD; Dikes: vertical thin, sheet of magma thrust upward into preexisting rock, occur as radial walls extending out from volcano, Shiprock, NM;
Sills: long, thin igneous rock intrusion formed when magma is forced between strata that are already in place, often btwn horiz and sedimentary layers;
Diastrophism – deformation of Earth’s crust due to pressure: folding- when rock structure are subjected to great compressional stresses over long periods of
time: anticline- upfolds that form ridges, synclines- downfolds that form valleys; faulting- breaking and displacement of a rock structure
External processes that shape the landscape: weathering, mass wasting, erosion; denudation- overall effect of disintegration, wearing away and removal of
rock material; Mechanical weathering: frost shattering: freeze/thaw action of water, ice wedges down in openings, ice melts and expands as water to create
crack, salt wedging: pries off mineral grains, occurs when salts crystallize out of solution when water evaporates, temperature changes that aren’t related to
freeze/thaw, exfoliation; Chemical weathering: a) decomp. of rock through chem. alteration of minerals, b) processes involving water and assisted by root
activity, c) chemical reactions cause rock disintegration by swelling and softening, d) positively charged hydrogen ions and negatively charged hydroxyl ions
are quick to interact w/ the mineral of rocks, e) most effective where moisture and temp. are high THREE TYPES: 1) oxidation: involving oxygen- soils and
rocks turn brown b/c oxidation of iron-bearing minerals 2) hydrolysis: union of water w/ other substance= new component that is softer and weaker (igneous
rock), silicate material combined w/water causes expansion and contributes to mechanical disintegration 3) carbonation: reaction btwn CO2 in water and
carbonate rocks to produce calcium bicarbonate which is a vary soluble product, either carried away in run-off or deposited in crystalline form if water is
evaporated; Biological Weathering: Root Activity- penetration of growing plant roots into cracks and crevices which opens cracks further and contributes to
mechanical weathering Lichens- algae and fungi living as a single unit on bare rock soil or bark, draw mineral from the rock by ion exchange which weakens
the rock, expansion and contraction of lichens during wet and dry period flake off tiny particles of the rock Burrowing Animal- mixes soils and can be a factor
in rock disintegration; Exfoliation- physical and chemical weathering process where curved layers of bedrock peel off in sheets; occurs when curved and
concentric joints develop in bedrock weathering, letting water in; often lichen and frost shattering contribute; layers are removed, expansion of rock occurs;
Types of mass wasting - downslope movement of material; related to slope angle, material forming the slope and moisture content; 1) rock fall: falling pieces
of rock downslope, referred to as talus or scree 2) land slide: instant mass slope collapse/no fluid flow, initiated from added weight from rainfall or
earthquakes, rock avalanches, lost material 3) creep: unobstrusive downslope flow of soil and regolith, freeze/thaw and wet/dry effects of creep, burrowing
animals and plant root effects 4) slump: slope collapse, concave in nature 5) mud flow: wasting initiated or enhanced by addition of water, water saturated by
land moved downhill, originate in arid basins 6) rock glaciers: need a climate cold enough to keep permafrost while regular glaciers flow, rock glaciers
“creep”; Primary agents of erosion – Fluvial: overall flow of water eroding, transporting & depositing material; Aeolian: erosion, transport, and deposition of
material b/c of wind; both produce variety of landscapes
Running water as one of the most important external process shaping the landscape; Erosion- picking up material, deepening valleys, canyon dvlopment;
Transportation- moving sediments, dissolved load: fine particles dissolved, suspended load: particles carried in suspension, bed load: heavy particles (rocks,
boulders) bounced/rolled along bottom; Deposition of sediments; Stream organization: drainage basin/watershed- work to remove surface run-off from an
area, areas that drain to valley, drainage divide; stream order- hierarchy in order within drainage network, smaller streams join larger ones; Drainage patterns:
Dendric- treelike pattern w/random stream merging, most common, Trellis- areas of hard &soft bedrock in clost contact, ridge&valley province of
Appalachians and Ouachita Mtns. Radial- dvlp around elevated central pt- mountain/volcano, Centripetal- converge into uniform basin, Annular- areas of hard
and soft domes or basins, Deranged- from disruption of pre-existing drainage pattern, not coherent, fault line, glaciation, Perennial: permanent, intermittent:
seasonal, Valleys- when drainage basins become well established, Interfluve- higher land above valley walls that separates adjacent walls; Potential energyincreased slope, increased PE; Kinetic energy- energy of motion of stream flow- velocity, laminar: slow, turbulent: fast; Gravity- assists flow- enhances
velocity; Friction- nature of sides and bottom, smooth- faster velocity, less friction, rough- slow velocity, more friction; Factors of energy- how much erosion
and deposition will occur: Stream discharge- volume of water carried, changes in response to PPTN; Stream velocity- how fast its moving, effected by stream
gradient and friction; River patterns- Straight: short and indicates strong geologic structure control, Sinuous: irregular and gentle curvature, Meandering:
highly variable curvature, Braided: multiple interwoven channels separated by loose bars; Flood plains- wide low-laying areas around a river; Levees- low
banks that keep stream in channel during normal flow; Terraces- elevation change = gradient increase, river has more energy so downcuts creating new flood
plain of deposition, abandoned flood plain above is river terrace; Bluffs/escarpments- rivers cut deeper leave behind bluffs or escarpments, steep slopes at outer
edge of a floodplain; Alluvial fans- arid regions, fan shaped landform that develops when high velocity stream carrying large bed load discharges load into
broad valley floor, often develop mountain canyon; Deltas- humid regions, similar process, Mississippi Delta; Yazoo Streams- tributary stream that runs
parallel to & within floodplain of a larger river which the stream eventually joins
Aeolian Landforms - wind as a geomorphic agent of erosion, transportation, and deposition, needed: lack of vegetation and wind less than 10 MPH; Loess
deposits- wind deposited silt, lacks stratification, great vertical durability, 10% of earth covered; Sand Dunes- easily moved, semi arid to desert dunescapes,
lack of vegetation and PPTN, fine sand laid as thin coating, Barchan- individual dunes migrating, crescent shaped, Transverse- crescent shaped but entire
landscape made of dunes, Seifs- long narrow parallel dunes, Coastal Dunes- ocean waves deposit sand on beaches, shore winds move sands inland; Rock
Arches- pinnacles, develop when wind slowly erodes sedimentary rock leaving behind arches; Deserts – specialized environment reflecting the
interrelationships between many factors; mechanical weathering, thin soil, abundance of soil, PPTN, wind, landforms Erg- sea of sand, Reg- surface covered
w/coarse gravel, pebbles or boulders. Desertification- expanding of desert, Africa, ME, Australia, Chile and Peru, India, Mexico, 8,100 sq mi each yr, affects
on human population; Differential Physical/Chemical Weathering of Sedimentary Rocks: Easily erodible shale evolves into lowlands or dissected slopes and is
carried away as bedload; Slowly eroding sandstone often forms ledges and cliffs; Pinnacles- pillar; Buttes- erosional remnant, small surface area, cliffs that rise
above surroundings; Mesas- Spanish for “table,” flat top surface; Plateaus- flattish platform w/escarpment on at least one side; Cuesta- Spanish slope, ridge
formed by gently dipping sedimentary rock, steep slope where rock exposed; Hogback- ridge with steep sides formed by dipping strata; Badlands- barren
terrain of easily eroded rock by fluvial processes, ravines, gullies, lifeless, nearly impassable; Scarp- escarpment=steep cliffs
Pleistocene Ice Age: 2.5 mil- 10,000 yrs ago; several interglacial periods followed by periods of advance, at peak 1/3 land covered in ice.; Contemp.
glaciation- Greenland and Antarctica have 96% total ice cover, 7% oceans ice in winter, 10% land ice covered, 22% land covered by seasonal snow and
permafrost; climate change related to contemporary glaciation; Indirect effects: periglacial zone- where ice never existed but glacial factors affected the
landscape such as erosion from ice melt, solifluction; sealevel changes- buildup of ice on continents led to less drain water on continents and brought about a
lowering of sea levels; crustal depression- weight of ice on continents caused continents to sink, ice melt allowed for continental rebound (isostasy); pluvial
developments- considerable runoff results in increased moisture leading to increased precipitation and less evaporation (Great Salt Lake) 2 types glaciers:
Continental- non-mountainous areas, today Antarctica and Greenland, outlet glaciers, ice shelf, ice bergs, vast thick blankets, thickest interior, thinner edges;
ice flowed outward from center of accumulation, ice sheets ebbed and flowed with changing climate; Mountain- highland ice fields- ice accumulates in
unconfined sheets in high mountain areas, outlet form valley glaciers, alpine glaciers- glaciers that develop individually in mountains, cirques- small alpine
glaciers confined to small basins, piedmont glacier- leading edge of valley glacier reaches a flat area; Formation- balance between accumulation and ablationwasting of glacial ice through melting or sublimination, snow beings as crystallized water vapor; compressed to granular form, more compression causes
granules to coalesce, further compression results in glacial ice, accumulation of snow greater than melting; Pressure from accumulated ice causes Flow- orderly
sliding of ice molecules; plastic flow- due to weight; basal slip- sliding occurring on bed of glacier, molds itself to landform; glacier advance- forward motion;
Erosion- plucking- rock broken due to frost shattering and picked up by advancing glaciers, irregular surface left, abrasion- rocks picked up by glaciers scrape
and smooth the surface; Transportation-glaciers carry material, meltwater under and on opt of glacier carries sediments and rocks; Deposition- drift- any debris
moved by glaciers (ice and meltwater), till- debris moved directly by glacier ice only (rough, rocky, irregular debris); Landforms: Continentalerosion=smoothing, carving (lake), bedrock grooves, steepening cliffs, cutting valleys, deposition- moraine: mounds of till left by retreating glaciers, drumlins:
mounts of till reworked by later advances of ice, kettle: depression left where blocks of ice were deposited then ice melted; Glaciofluvial Features- outwash
plain: smooth flat alluvial plain deposited beyond moraines by streams issuing from ice, eskers: ridges of sand and gravel that fall out from meltwater, finger
lakes: valleys carved out by ice sheets and filled w/water to create lakes; Mountain- cirque: bowl shaped depression in mountain peak carved out by ice horn:
pyramid shaped peaks left when cirques are cut back into a mountain peak from 3 or 4 sides, arête: jagged ridge crests formed when glaciers cut into a ridge
from both sides
Karst Topography- landforms that develop in humid areas from dissolution of limestone; barren land, special landforms that develop on exceptionally soluble
rocks usually evolve where massive limestone bedrock; Dissolution: removal of bedrock through chemical action of water; Precipitation: mineralized water
trickling in along cave roof/wall; Weathering of limestone: dominant material calcite, dissolves in slightly acidic water creating a carbonate solution that
dissolves the limestone, dissolution of limestone by carbonic solution at both surface and subsurface results in Karst topography; Caverns: created by
solution along joints and bedding planes in limestone beneath surface, stalactite- pendant structure grown downward where water drips from roof, stalagmitegrows upward where drip hits floor; Sinkholes: most common Karst feature (dolines); rounded depressions formed by the dissolution of surface carbonate
rocks at joint intersections, uvala: chain of intersecting sinkholes; Underground Streams: streams disappear into sinkholes and flow underground until they
reappear; Hot Springs: hot water at Earth’s surface that has been forced upward through fissures or cracks by the pressures that develop when underground
water has come in contact with heated rocks or magma beneath surface; Mineral deposits/limestone terraces: where springs emerge onto flat land there may be
cones, domes or irregular concentric deposits, deposits resulting from geysers less than those from hot springs, largely massive (travertime) or porous
(tufa/sinter) accumulations of calcium carbonate from hot springs; Geysers: special form of intermittent hot spring w/ water issuing only sporadically as a
temporary ejection in which hot water and steam are spouted upward for some distance