Lesson 1 Flashcards
internal forces which derive their strength from the earth’s interior and play a crucial role in shaping the earth crust.
Endogenic forces
Examples of endogenic forces
mountain building forces, continent building forces, earthquakes, volcanism etc
mainly land building forces
endogenic forces
main force behind endogenic geomorphic processes
energy emanating from within the earth
This energy is mostly generated by ________, ________ and __________ and __________
radioactivity, rotational, tidal friction, primordial heat
forces which derive their strength from the earth’s exterior or are originated within the earth’s atmosphere.
Examples of exogenic forces
Wind, waves, water
Examples of exogenic processes
Weathering
Mass movement
Erosion
Deposition
Mainly land wearing forces
Exogenic forces
Breaking of rocks on the earth’s surface by different agents like wind, sea, and glaciers
Weathering
Examples of geomorphic agents
Running water
Groundwater
Glaciers
The wind
Waves
Currents
A force applied on earth’s materials affecting the same
Geomorphic processes
A mobile medium (like running water, moving ice masses, wind, currents, etc.) which removes, transports and deposit earth materials
Geomorphic agents
Movements in the earth’s crust caused by the endogenic or exogenic forces
Earth movements
Earth movements are also termed as
Tectonic movements
Tectonic is derived from ‘Tekton’, Greek for?
Builders
Responsible for building up landforms
Earth movements
Tectonic movements
Processes which occur on earth’s surface due to the influence of exogenic forces are called
Exogenic forces or exogenic geomorphic forces
Weathering, mass wasting, erosion,
and deposition are the main exogenic processes. All the exogenic processes are covered under a
general term-
Denudation
Meaning of denudation
strip off or uncovers
The action of elements of weather and climate over earth material.
It can be defined mechanical disintegration and chemical decomposition of rocks through the actions of various elements of weather and climate
Weathering
Some minerals are removed, soo the minerals increase and make it more valuable. True or false?
True
Physical or mechanical weathering processes depend on some applied forces.
The applied forces could be:
gravitational forces
expansion force
water pressure
gravitational forces? bc of physical/mechanical weathering
overburden pressure, load, and shearing stress
expansion forces due to? bc of physical/mechanical weathering
temperature changes, crystal growth or animal activity
- Removal of overlying rock load because of continued erosion causes vertical pressure release.
- Thus, the upper layers of the remaining rock expand to produce disintegration of rock masses.
- Fractures will develop roughly parallel to the ground surface.
Unloading and expansion
- In areas of curved ground surfaces, arched fractures tend to produce massive sheets
exfoliated slabs
_________is a result but not a process. Flaking off of more or less curved sheets of shells from
over rocks or bedrocks results in smooth and rounded surfaces.
Exfoliation
So, unloading and expansion create large, smooth rounded domes called ____
exfoliation domes
smooth surfaced and rounded small to big boulders called _______ form due to such exfoliation
tors
- With rising in temperature, every mineral expands and pushes against its neighbor and as the temperature falls, a corresponding contraction takes place.
- Due to differential heating and the resulting expansion and contraction of surface layers and their subsequent exfoliation from the surface results in smooth rounded surfaces in rocks.
Temperature changes and expansion
Cycles of freezing and thawing (the weather becomes warmer and causes snow and ice to melt)
causes
frost weathering
Where is frost weathering most effective?
high elevations in mid-latitude where freezing and melting is often repeated
explain freezing, thawing, and frost wedging (frost weathering)
Rapid freezing of water causes its sudden expansion and high pressure. The resulting expansion affects joints, cracks, and small intergranular fractures to become wider and wider till the rock breaks apart.
Salts in rocks expand due to thermal action, hydration and crystallization.
Salt weathering
Example of salts that expand
calcium, sodium, magnesium, potassium and barium
_______ is the most effective of all
salt weathering processes. It is favored in
areas of alternative wetting and drying
conditions
Salt crystallization
can be due to solution, carbonation, hydration or oxidation/reduction.
Chemical weathering
When something is dissolved in water or acids, the water or acid with dissolved content is called
solution
This process involves removal of solids in solution and depends upon the solubility of a mineral in
water or weak acids
solution
how solution works
- coming into contact with water, lotsa solids disintegrate
- so that forms minerals like nitrates, sulphates, potassium etc
- occurs in rainy
- common salt is also a rock forming mineral and is susceptible to this process
extra info on solution
the reaction of carbonate and bicarbonate with minerals and is common process helping to break down of feldspar and carbonate minerals
Carbonation
how does carbonation happen?
CO2 from everywhere absorbed by water forms carbonic acid, which is weak
- results in cave formation
chemical addition of water
Hydration
how hydration work?
- Minerals take up water and expand –> increase in the volume of the material itself or rock.
- The process is reversible and long, repetition –> disintegrate
- calcium sulphate takes in water and turns to gypsum, which is more unstable than calcium sulphate
means a combination of a mineral with oxygen to form oxides or hydroxides
Oxidation and reduction
Minerals most commonly involved in oxidation is?
iron, manganese, Sulphur, etc
how oxidation work?
rock breakdown occurs due to the disturbance caused by the addition of oxygen (that’s why OXidation)
- btw, without oxygen, but there is oxidized minerals, reduction happens
several biological activities like growth or movements of organisms
Biological weathering
biological weathering, how it works?
- nature
- they bring in conditions for physical or chemical weathering
When these smaller pieces (from weathering), called pebbles, sand, or soil, begin to move by natural
forces, it is called ______
Erosion
Erosion can happen either supa fast or supa slow, like millions of years slow.
omoidashite
Main cause of erosion
water
Two other main forces of erosion? (dw this is minor)
wind
ice
glaciers slowly move, carving out valleys —> that is ____
erosion too :D
once the movement of sediment, such as pebbles, sand, mud or even boulders reach their final destinations, it is called _______
deposition
types of weathering?
mechanical
chemical
biological
Erosion also affects the level of sorting– what is sorting?
separating of items into groups according to one or more properties, in this case, it’s size
When sediment has been moved a lot by wind or waves, it is ____
well-sorted
intriguing landforms are found along coastlines
Sea Stacks
Landforms produced by erosion are often tall, jagged structures with several exposed layers of rock
fun fact
- The Tepees in the Painted Desert of Arizona
erosion ex.
Landforms created by deposition are often
flat and low-lying.
An apron of sediment, called an ________, often forms where a stream flows from a steep, narrow canyon onto a flat plain at the foot of a mountain.
alluvial fan
produces ice-carved features in mountains, like jagged mountain peaks and u-shaped valleys
Glacial Erosion
cause of coastal erosion
Currents and waves
a large deposit of sediment that forms where a stream enters a large body of water
delta
the grinding away of rock or other surfaces as particles carried by wind, water, or ice scrape against them
abrasion
a pile of windblown sand
dune
Structures in caves that form by deposition from cave ceilings and floors are
stalactites and stalagmites
