Post on 08-Mar-2018
6/19/2011
1
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
Geomorphology (Greek: γῆ, ge, "earth"; μορφή, morfé, "form"; λόγος, logos, "study")
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
IntroductionIntroduction
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Tends to focus around histories or trajectories of landscape evolution and adopts a sequential, chronological view
IntroductionIntroduction
Peneplain concept
‐ ‘geographical cycle’
‐ William Morris Davis and Walther Penck
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Holmes, 1965; Huggett, 2011
Geomorphology (Greek: γῆ, ge, "earth"; μορφή, morfé, "form"; λόγος, logos, "study")
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
IntroductionIntroduction
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
Geomorphology (Greek: γῆ, ge, "earth"; μορφή, morfé, "form"; λόγος, logos, "study")
Applied Geomorphology
Tectonic Geomorphology
IntroductionIntroduction
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Submarine Geomorphology
Planetary Geomorphology
Climatic Geomorphology
6/19/2011
2
‐ 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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Geomorphic processes and evolution of landformsGeomorphic processes and evolution of landforms
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
world seismicity map taken from the Tectonics Observatory websitewww.nature.nps.gov/GEOLOGY/usgsnps/animate/A58.gif
Volcanic processes and landformsVolcanic processes and landforms
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Tsutsumi and Perez, 2010Mindanao Island, Philippines
HillslopesHillslopes and mass wastingand mass wasting
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
www.defense.gov/home/features/Leyte/landslide/images/hi-res/060219-N-5067K-109.jpg
Southern Leyte, Philippines
6/19/2011
3
Fluvial processes and landformsFluvial processes and landforms
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
365greatpinoystuff.files.wordpress.com/2010/06/chico-river-aerial.jpg
Kalinga, Philippines
KarstKarst topographytopography
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
Ilocos Norte, Philippines
Aeolian processes and landformsAeolian processes and landforms
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
6/19/2011
4
‐ 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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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
N. Ramos | Geology 122 Principles of Geomorphology Basic concepts
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