Diapositiva 1

Unit 11. The evolution of landformsBiology and Geology. 4 ESOIES Antonio Gala

1. An overview of landforms

Landscape Vs. Landform(match both columns)1. LandscapeA. a naturallyformed feature on theEarths surface, having acharacteristic shape or form2. Landform B. visiblefeatures of an area includingboth the natural (mountains,forests, rivers etc) andhuman elements (roads,houses, bridges etc)

.Landforms of varying sizes and shapes, when taken together, are referred to as a landscape The landforms have relationships with each other, which means they form distinctive groupings in these different landscapes.Some landforms are extensive (dune fields) and others are small (group of rocks)Geomorphology examines landforms, concentrated on the surface of the lithosphere, and the processes producing them.

CHANGES ON RELIEF

External energyInternal energy

Sun energy and gravity

EXTERNAL GEOLOGICAL PROCESSESRelief destructionGeothermal energyINTERNAL GEOLOGICAL PROCESSES

Relief construction

ClimateLithologyHuman actionsTectonic plates dynamics

External geological AGENT

External geological PROCESS

LANDFORM of relief

The one who creates the reliefRiver, wind, sea, glacier, rain,The action to create the reliefWeathering, erosion, transportation, sedimentationThe resultdune, beach, valley, caves, cliff, The river erodes the mountain and as a result we have a valley

2. Lithological landforms

2.1. Volcanic landforms

What is this feature and what landform does it belong to?

Lithological landformsVolcanic landformsOriginal landform: lava fields

What is this feature and what landform does it belong to?

Lithological landformsVolcanic landformsOriginal landform: craters and conical edifices

What is this feature and what landform does it belong to?

Lithological landformsVolcanic landforms BASALT (VOLCANIC ROCK)Derived landform: lava plateau (Giants causeway in Ireland)

Columbia river plateau. Washington state. USA

Columbia river plateau. Washington State. USA

What is this feature and what landform does it belong to?Kaguyak volcano (Alaska) 2.5 km in diameter

Lithological landformsVolcanic landformsDerived landform:caldera (Yelowstone caldera)

Yellowstone National Park

2.2. Granite landforms

What are these features and what landform do they belong to?

Lithological landformsGranite landformsDomes (rounded blocks) and outcrops (straight blocks)Boulder (domes generally piled up)

Process of weathering in graniteStep 1At the beginning granite is already fractured in the subsurface. These fractures become more intense with the time and build a network that splits the granite into blocks of cube-like shape.

Step 2When the fractures come into contact with rain water, that seeps into the cracks. At night temperature decreases enough to freeze water into ice, which expands and breaks the corners. The building of boulders starts. The decay of the corners results in granite boulders of spheroidal shape.

Step 3: The last step is erosion of the decayed granite sand that exposes these spheroidally-weathered boulders at the surface.

2.3. karst landforms

What are these features and how are they produced?

Limestone carbonation

aSolid rockDissolved salt (solution)12DissolutionPrecipitation

What are these features and what landform do they belong to?

Lithological landformsKarst landforms: endokarstic landformsCaves or caverns (large cavities formed when smaller spaces join together due to the dissolution of limestone)Stalactites (precipitated calcium growing from the ceiling)Stalagmites (precipitated calcium growing from the ground)

Dissolution and precipitation of limestone

Evolution of karst landforms

What has happended here as time went by very slowly.?

Ceiling of caves can collape or dissolve completelyTorcal de Antequera (Mlaga. Spain)

Canyons

Torcas and RavinesWhich is each one?

3. Climate landforms

3.1. LANDFORMS IN COLD ZONES

Glacial landforms

GLACIER FORMATION1 It severely snows

GLACIER FORMATION2 The snow accumulates in the cirque and it is transformed into ice because of its weight and low temperatures

cirque

GLACIER FORMATION3 Due to the weight the ice goes down and forms the TONGUE

tonguecirque

GLACIER FORMATIION4 On its way down the glacier erodes and transports materials (sediments).

cirquetongue

GLACIER FORMATION5 when the ice melts, rivers are formed and materials are deposited forming moraines

cirquetongueterminus

GLACIER FORMATION6 The glacier disappears thousands of years later but the landforms remain.

cirqueGlacial cirqueU-shaped valley

TaskWrite the name of the landform, agent and process of the following photos.

Glacial cirque Glacier Erosion

Glacial lake Glacier Erosion

Rocks with glacial striations GlacierTransportation

Valle de OrdesaU-shaped valley GlacierErosion

Till /Morrains GlacierSedimentation

3.2. LANDFORMS IN TEMPERATE ZONES

Dry temperate zones: Semi-desert landforms

Gullies, torrential rain, erosion

Morocco

Utah USAHoodoo or fairy chimneys / Torrential rain / Weathering and erosion

Fluvial landforms

Water fall RiverErosion

V-shaped valley RiverErosion

Delta RiverSedimentation

Gorge RiverErosion

MeandersRiverErosion/Deposition

3.3. LANDFORMS IN HOT ZONES

Desert landforms

Mushroom-shaped rock, Wind, Erosion

Crescent (Barchan) Dunes, Wind, Deposition

What is this feature and what landform does it belong to?

What is this feature and what landform does it belong to?

Star Dunes, Wind, Deposition

Arches, Wind, Weathering & Erosion,

4. Structural landforms

What are these features and what landform do they belong to?

Structural landformsLandforms in horizontal regions: table mountains or plateaus, monadrocks or isolated ridges

What are these features and what landform do they belong to?

Structural landformsLandforms in folded regions: hills and crests

What are these features and what landform do they belong to?

Structural landformsLandforms in fractured regions: horst and graben

________ fault?

5. Coastal landforms

Cape /baySeaErosion

CliffSeaErosion

Wave-cut platformSeaErosion

Zumaia, Euskadi

cliffcliffcliffcliffseaseaseaseaEroded materialsAbrasion platformAbrasion platform

Las catedrales, GaliciaArchesSeaErosion

Mar Menor (Murcia)LagoonSeaSedimentation (sand bar)

DoanaMarshSeaSedimentation (in an estuary)

T H E E N D