1 Basic concepts - Webs Basic concepts.pdf · Peneplain concept ‐‘geographical ... Geomorphic...

6/19/2011

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Introduction:Introduction:Basic concepts of geomorphologyBasic concepts of geomorphology

Palawan, Philippines

Geomorphology (Greek: γῆ, ge, "earth"; μορφή, morfé, "form"; λόγος, logos, "study")

‐ study of landforms and the processes that shape them

• to understand why landscapes look the way they do• to understand landform history and dynamics• to predict future changes through a combination of field observation,

IntroductionIntroduction

N. Ramos | Geology 122 Principles of Geomorphology Basic concepts

p g gphysical experiment, and numerical modeling

‐ mechanics of modern processes and the historic influence of geologic time


Historical GeomorphologyStudy of landform evolution or changes in landforms over medium and long timescales, usually timescales well beyond the span of an individual human’s experience



Tends to focus around histories or trajectories of landscape evolution and adopts a sequential, chronological view


Peneplain concept

‐ ‘geographical cycle’

‐ William Morris Davis and Walther Penck


Holmes, 1965; Huggett, 2011


Historical GeomorphologyStudy of landform evolution or changes in landforms over medium and long timescales, usually timescales well beyond the span of an individual human’s experience



Tends to focus around histories or trajectories of landscape evolution and adopts a sequential, chronological view

Process GeomorphologyStudy of processes responsible for landform development

Tends to focus around the mechanics of geomorphic processes and how geomorphic systems respond to disturbances


Applied Geomorphology

Tectonic Geomorphology



Submarine Geomorphology

Planetary Geomorphology

Climatic Geomorphology

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‐ distinctive landscape and characteristic landforms from which the origin of the forms can be identified

‐ landforms evolve as a result of continuous changes in processes and rates as time goes on

Geomorphic processes and evolution of landformsGeomorphic processes and evolution of landforms


Geomorphic processes and evolution of landformsGeomorphic processes and evolution of landforms


world seismicity map taken from the Tectonics Observatory websitewww.nature.nps.gov/GEOLOGY/usgsnps/animate/A58.gif

Volcanic processes and landformsVolcanic processes and landforms


aroundthephilippines.com/wp-content/uploads/2011/05/Mayon_Volcano_Eruption_2.jpgupload.wikimedia.org/wikipedia/commons/8/81/Mt.Mayon_tam3rd.jpg

Albay, Philippines

Shishikura, 2003

M7.9 1923 Taisho

M8.2 1703 Genroku

Tectonic processes and landforms: UpliftTectonic processes and landforms: Uplift

Mw9.2 2004 Sumatra - Andaman Mw8.7 2005 Nias – Simeulue

Photos: Tectonics Observatory , California Institute of Technology

Tectonic processes and landforms: DisplacementTectonic processes and landforms: Displacement

kagi.coe21.kyoto-u.ac.jp/images/t_images/tidbit17_2.gif

Nueva Ecija, Philippines


Tsutsumi and Perez, 2010Mindanao Island, Philippines

HillslopesHillslopes and mass wastingand mass wasting


www.defense.gov/home/features/Leyte/landslide/images/hi-res/060219-N-5067K-109.jpg

Southern Leyte, Philippines

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Fluvial processes and landformsFluvial processes and landforms


365greatpinoystuff.files.wordpress.com/2010/06/chico-river-aerial.jpg

Kalinga, Philippines

KarstKarst topographytopography


www.travel-visit-places.com/wp-content/uploads/image/Chocolate%20Hills/natural-wonder-chocolate-hills.jpg

Bohol, Philippines

Coastal processes and landformsCoastal processes and landforms


Ilocos Norte, Philippines

Aeolian processes and landformsAeolian processes and landforms


v1.cache2.c.bigcache.googleapis.com/static.panoramio.com/photos/original/41984288.jpg?redirect_counter=1

IlocosIlocos Norte, PhilippinesNorte, Philippines

Glacial/Glacial/periglacialperiglacial processes and landformsprocesses and landforms


upload.wikimedia.org/wikipedia/en/e/ec/Circosabisko.jpgLapland, Sweden

Huon Peninsula, PNG Muroto Peninsula, JP

Photo: National Oceanic and Atmospheric Administration, USA

Quaternary climate and sea level changeQuaternary climate and sea level change

Mahia Peninsula, NZ

Photo: Ministry for Culture and Heritage, NZ

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‐ Henry Louis Le Chatelier; Grove Karl Gilbert

‐ negative feedback systems

‐ a system in which a delicate balance exists between opposing forces such that any change in the variables that control the system produces a change in one or more of the other variables to generate a new balance

e g graded stream

Geomorphic systems: Equilibrium systemsGeomorphic systems: Equilibrium systems


e.g. graded stream

Steady StateConditions change very little with time

DecliningRate of change declines with time to successively lower rates

DynamicSmall variations about a changing average condition

‐ positive feedback systems

‐ occurs when a change in the input variable causes magnification of change in the direction of the initial adjustment

e.g. meanders and formation of oxbow lakes

Geomorphic systems: NonGeomorphic systems: Nonequilibrium systemsequilibrium systems


e.g. meanders and formation of oxbow lakes

‐ carry the source of their own destruction and eventually accelerate to self‐elimination

Uniformity of lawNatural laws are invariant in time and space

Principle of simplicity/Uniformity of processNo extra, fanciful, or unknown causes should be invoked if available processes will do the job

Gradualism, uniformitarianism and catastrophism

Geomorphology ‘rules’/guidelinesGeomorphology ‘rules’/guidelines


p• rates of surface processes may have varied in the past• processes may have existed in the past but may not be operative at present

Steady –stateism and directionalismConstant state of the earth’s surface

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