Tectonic and Structural Landforms Both endogenic Both endogenic Create large-scale landforms Create...
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Transcript of Tectonic and Structural Landforms Both endogenic Both endogenic Create large-scale landforms Create...
Tectonic and Structural Tectonic and Structural LandformsLandforms
• Both endogenicBoth endogenic• Create large-scale landformsCreate large-scale landforms• TectonicTectonic
– produced by deep Earth process without produced by deep Earth process without erosionerosion
• StructuralStructural– the result of exogenous forces acting on the result of exogenous forces acting on
tectonic landformstectonic landforms
Structural LandformsStructural Landforms
• Convergent tectonic forces produce fold Convergent tectonic forces produce fold structuresstructures– anticlines, synclines, monoclines, dome, basinsanticlines, synclines, monoclines, dome, basins
• Compressive or tensional forces produce Compressive or tensional forces produce faultingfaulting– fault scarps, horsts, grabensfault scarps, horsts, grabens
• Faults and folds impart relief to the Faults and folds impart relief to the landscape (until erosion gets to them)landscape (until erosion gets to them)
StructureStructure
• the attitude of a bed or stratum of the attitude of a bed or stratum of beds or strata of sedimentary rocks, beds or strata of sedimentary rocks, as indicated by the dip and strike.as indicated by the dip and strike.
• the disposition of the rock the disposition of the rock formations; i.e., the broad dips, folds, formations; i.e., the broad dips, folds, faults, and unconformities at depth faults, and unconformities at depth
Strike and dipStrike and dip
LithologyLithology• Relative erodibilityRelative erodibility
– Layered rocks = wide rangeLayered rocks = wide range•SedimentarySedimentary
•VolcanicVolcanic
– Massive rocks = narrow rangeMassive rocks = narrow range•MetamorphicMetamorphic
• Intrusive igneousIntrusive igneous
– Erodibility is Erodibility is notnot absolute absolute•typicallytypically shale > limestone > sandstone shale > limestone > sandstone
~ gneiss~ gneiss
LithologyLithology
http://www.uwgb.edu/dutchs/EarthSC202Notes/sedrocks.htm
Environment During Deposition
Lithology/ClimateLithology/Climate
Landforms assoc. with sedimentary Landforms assoc. with sedimentary rocksrocks
• Horizontal bedsHorizontal beds– plateau, mesa, table, butteplateau, mesa, table, butte
• Folded bedsFolded beds– anticline (arches in strata), syncline anticline (arches in strata), syncline
(trough in strata), cuesta, hogback(trough in strata), cuesta, hogback
TablelandsTablelands
• Plateau/mesa/butte/chimneyPlateau/mesa/butte/chimney
http://maunakea.com/patsadv/gallery.htm
TablelandsTablelands
Tilted Layer Tilted Layer CakesCakes
• Monoclinal foldingMonoclinal folding– beds are flexed from beds are flexed from
one level to anotherone level to another
• Feature = f(dip angle)Feature = f(dip angle)– Cuesta (gentle)Cuesta (gentle)– Hogback (steep)Hogback (steep)– Flatiron (very steep and Flatiron (very steep and
supported)supported)
• Also f(rel. erodibility)Also f(rel. erodibility)• Drainage patternsDrainage patterns
– ParallelParallel– TrellisTrellis
http://www.geog.ouc.bc.ca/physgeog/contents/10l.html
http://www.uwgb.edu/dutchs/EarthSC202Notes/sedrocks.htm
Landforms Associated with Sedimentary Rocks
Mesa Flat-topped hill capped with hard rock
Cuesta Gently-tilted layer of hard rock. The gentle upper slope, on top of the layer is called the dip slope
Hogback A sharp ridge of hard rock, edge of a steeply-dipping layer
Monocline:“A double flexure connecting strata at one level with the same strata at another level”G.K. Gilbert
RidgesRidges• Cuestas and hogbacksCuestas and hogbacks
Copyright © J. Michael Daniels 2002http://www.alperry.com/coal/grand_hogback.html
“Strike”
DipSlope
ScarpSlope
“Dip”
“Contact”
Kd
Kd
Jm
Jm
Delaware MIDelaware MIR
esistant units are typically <100’ thick and dip N
at 10-16°
1610 15
Folded Rocks – SimpleFolded Rocks – Simple http://www.geog.ouc.bc.ca/physgeog/contents/1http://www.geog.ouc.bc.ca/physgeog/contents/10l.html0l.html
• Anticline/synclineAnticline/syncline
Folded – Folded – still simplestill simple
• PlungingPlunging– Z-foldsZ-folds
Simple folds - drainage
• Contorted– Metamorphic?
• Inward/outward–Radial
–Centripetal
• Ringlike - annular
Folded Rocks - Complex
Folded Rocks - Complex
Weak
Strong
Weak Strong
“scarp slope”“dip slope”
Horseshoe Hills.kmzHorseshoe Hills
Bluntsynclinal
nose
Bluntsynclinal
nose
Sharpanticlinal
nose TOPOGRAPHY
STss