The processes that shape the Earth's surface from forces above and at the surface are called exogenetic processes. These include processes of degradation that destroy material and processes of aggradation that build up material. Processes of degradation are weathering, mass movement, erosion, and transportation. Weathering breaks down rocks through physical and chemical processes. Physical weathering is caused by factors like temperature changes, frost action, and plants and animals. Chemical weathering results from reactions with substances like water, carbon dioxide, and oxygen. These exogenetic processes gradually wear down and alter the Earth's surface over time.
this presentation is all about weathering, erosion, & mass wasting. this may be simple, but it is good for the eyes, and the information is short but complete. :))
Gravity pulls the rocks, soils and debris on a downward slope, naturally, without any chemical change. This downward movement is called as mass -movement or mass-wasting.
Landslides, mudflows and rockfalls are all belonging to this category of geomorphic processes.
Mass-wasting may lead to severe natural disasters by affecting the life and building structures in different places. Understanding of mass-wasting will certainly help to mitigate the impacts of these hazards and plan the development activities.
Weathering is an important geological mechanism which can destabilize the earth’s surface materials and remove them by erosive processes. Weathering is the physical disintegration and chemical decomposition of a rock mass on the land. It is a unique phenomena happening on the earth’ surface. Weathering is a collective term used to denote the mechanical, chemical and biological(organic) processes that take place on the earth’s surface. Weathering of rock-forming minerals can create new products from pre-existing rocks. In many regions, soils are the ultimate products of weathering. Weathering of rocks releases chemical compounds that become available for biological processes. It is necessary to study the factors that are influencing the weathering processes.
this presentation is all about weathering, erosion, & mass wasting. this may be simple, but it is good for the eyes, and the information is short but complete. :))
Gravity pulls the rocks, soils and debris on a downward slope, naturally, without any chemical change. This downward movement is called as mass -movement or mass-wasting.
Landslides, mudflows and rockfalls are all belonging to this category of geomorphic processes.
Mass-wasting may lead to severe natural disasters by affecting the life and building structures in different places. Understanding of mass-wasting will certainly help to mitigate the impacts of these hazards and plan the development activities.
Weathering is an important geological mechanism which can destabilize the earth’s surface materials and remove them by erosive processes. Weathering is the physical disintegration and chemical decomposition of a rock mass on the land. It is a unique phenomena happening on the earth’ surface. Weathering is a collective term used to denote the mechanical, chemical and biological(organic) processes that take place on the earth’s surface. Weathering of rock-forming minerals can create new products from pre-existing rocks. In many regions, soils are the ultimate products of weathering. Weathering of rocks releases chemical compounds that become available for biological processes. It is necessary to study the factors that are influencing the weathering processes.
Core Subject: Earth and Life Science
II. Earth Materials and Processes
A. Minerals and Rocks
The learners
demonstrate an
understanding of:
1. the three main categories of rocks
2. the origin and environment of formation of common minerals and rocks
The learners:
1. identify common rock-forming minerals using their physical and chemical properties
2. classify rocks into igneous, sedimentary, and metamorphic
TRUE OR FALSE: The Earth’s surface has stayed the same for thousands of years
FALSE: the Earth’s surface is always changing
EXAMPLE
EROSION & DEPOSITION
EROSION
Is the process by which natural forces move weathered rock and soil from one place to another.
Sediment – material moved by erosion .
DEPOSITION
Occurs where the agents of erosion lay down sediment.
Mass Movement
Any one of several processes that move sediment downhill.
Different types of Mass Movement
Landslide
- occurs when rock and soil slide quickly down a steep slope.
Different types of Mass Movement
Mudflow
- mudflow is a rapid downhill movement of a mixture of water, rock, and soil.
Different types of Mass Movement
Slump
- a mass of rock and soil suddenly slips down a slope.
Different types of Mass Movement
Creep
- very slow downhill movement of rock and soil.
Water Erosion
Rills and Gullies
Rills
- tiny grooves in the soil.
Gully
- a large groove , or channel, in the soil that carries runoff after a rainstorm
Streams and Rivers
Stream
- a channel along which water is continually flowing down a slope.
River
- a large stream
Amount of Runoff
In an area depends on five main factors:
1st – amount of rain
2nd – vegetation
3rd – type of soil
4th – shape of the land
5th – how people use the land
Erosion by River
Through erosion, a river creates a waterfalls, flood plains, meanders, and oxbow lakes.
Waterfall
May occur where a river meets an area of rock that is very hard and erodes slowly.
Flood plain
Flat, wide area of land along a river.
Meander
A loop like bend in the course of the river
Oxbow lake
A meander that has been cut off from the river.
Deposits by River
Deposition creates landforms such as alluvial fans and deltas. It can also add soil to a river’s flood plain.
Alluvial Fans
A wide, sloping deposit of sediment formed where a stream leaves a mountain range.
Deltas
Sediment deposited where a river flows into an ocean or lake.
Groundwater Erosion
Groundwater can cause erosion through a process of chemical weathering.
Stalactite – hangs down from the roof of a cave.
Stalagmite – pointed piece of rock that sticks u p from the floor.
How Water Erode and Carries Sediment
Most sediment washes or falls into the river as a result of mass movement and runoff. Other sediment erodes from the bottom or sides of the river.
Abrasion- is the wearing away of rock by grinding action.
- occurs when particles of sediment in flowing water bumped into the steam again and again.
Erosion and Sediment Load
A river’s slope, volume of flow, and the shape of its trembled all affect how fast the river flows and how much sediment it can erode.
Slope
Is the amount the river drops toward sea level over a give distance.
Volume of Flow
A river’s flow is the volume of water that moves past a point on the river on a given time.
Streambed Shape
Affects the
Core Subject: Earth and Life Science
II. Earth Materials and Processes
A. Minerals and Rocks
The learners
demonstrate an
understanding of:
1. the three main categories of rocks
2. the origin and environment of formation of common minerals and rocks
The learners:
1. identify common rock-forming minerals using their physical and chemical properties
2. classify rocks into igneous, sedimentary, and metamorphic
TRUE OR FALSE: The Earth’s surface has stayed the same for thousands of years
FALSE: the Earth’s surface is always changing
EXAMPLE
EROSION & DEPOSITION
EROSION
Is the process by which natural forces move weathered rock and soil from one place to another.
Sediment – material moved by erosion .
DEPOSITION
Occurs where the agents of erosion lay down sediment.
Mass Movement
Any one of several processes that move sediment downhill.
Different types of Mass Movement
Landslide
- occurs when rock and soil slide quickly down a steep slope.
Different types of Mass Movement
Mudflow
- mudflow is a rapid downhill movement of a mixture of water, rock, and soil.
Different types of Mass Movement
Slump
- a mass of rock and soil suddenly slips down a slope.
Different types of Mass Movement
Creep
- very slow downhill movement of rock and soil.
Water Erosion
Rills and Gullies
Rills
- tiny grooves in the soil.
Gully
- a large groove , or channel, in the soil that carries runoff after a rainstorm
Streams and Rivers
Stream
- a channel along which water is continually flowing down a slope.
River
- a large stream
Amount of Runoff
In an area depends on five main factors:
1st – amount of rain
2nd – vegetation
3rd – type of soil
4th – shape of the land
5th – how people use the land
Erosion by River
Through erosion, a river creates a waterfalls, flood plains, meanders, and oxbow lakes.
Waterfall
May occur where a river meets an area of rock that is very hard and erodes slowly.
Flood plain
Flat, wide area of land along a river.
Meander
A loop like bend in the course of the river
Oxbow lake
A meander that has been cut off from the river.
Deposits by River
Deposition creates landforms such as alluvial fans and deltas. It can also add soil to a river’s flood plain.
Alluvial Fans
A wide, sloping deposit of sediment formed where a stream leaves a mountain range.
Deltas
Sediment deposited where a river flows into an ocean or lake.
Groundwater Erosion
Groundwater can cause erosion through a process of chemical weathering.
Stalactite – hangs down from the roof of a cave.
Stalagmite – pointed piece of rock that sticks u p from the floor.
How Water Erode and Carries Sediment
Most sediment washes or falls into the river as a result of mass movement and runoff. Other sediment erodes from the bottom or sides of the river.
Abrasion- is the wearing away of rock by grinding action.
- occurs when particles of sediment in flowing water bumped into the steam again and again.
Erosion and Sediment Load
A river’s slope, volume of flow, and the shape of its trembled all affect how fast the river flows and how much sediment it can erode.
Slope
Is the amount the river drops toward sea level over a give distance.
Volume of Flow
A river’s flow is the volume of water that moves past a point on the river on a given time.
Streambed Shape
Affects the
S6E5. Students will investigate the scientific view of how the earth’s surface is formed.
d. Describe processes that change rocks and the surface of the earth.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Thesis Statement for students diagnonsed withADHD.ppt
Exogenetic Process-Geomorphology Chapter
1.
2. The exogenetic processes are the processes that shape the land by forces
coming on or above the Earth's surface (exogenetic forces).
Exogenetic Processes
These are processes that take place on the earth's surface.
They are subdivided in two categories:
Processes of degradation
Processes of aggradation
Processes of degradation are those that destroy what has been built up by
endogenetic/aggradation processes. These are
Weathering
Mass movement
Erosion
Transportation
Processes of aggradation are those that build up material. Deposition
of weathered and eroded sediments
The destruction of the landscape is known as denudation.
Denudation is the long-term sum of processes that cause the wearing away
of the earth’s surface leading to a reduction in elevation and relief of
landforms and landscapes (weathering, erosion, and mass wasting).
3. • Weathering
• Weathering is the breaking and decomposition of rocks at/near the
earth's surface by physical & chemical processes.
• Weathering may be defined as the mehanical fracturing or chemical
decomposition of rocks by natural agents at the surface of the earth
(B.W.Sparks).
• Firstly, it involves two types of changes in the rocks
• (1) physical or mechanical changes, wherein rocks are disintegrated
through temperature changes (heat factor), frost action (frost factor),
biological activities (biotic factors), and wind actions. (2) chemical
changes wherein rocks are decomposed through static water, oxygen,
carbon dioxide, and biological activities.
• Secondly, the breakdown of rocks occurs at the place of rocks (in situ).
• Thirdly, there is no large-scale transport of weathered materials except
mass movement or mass translocation of weathered materials (rock-
waste) down the slope under the force of gravity.
4. • Factors Influencing the Character and Rate of
Weathering
• These factors include:
• A) Composition and structure of rocks: Mineral composition,
joint pattern, layering system, faulting, folding etc. largely affect
the nature and intensity of weathering. For example, carbonate
rocks having more soluble minerals are easily affected by
chemical weathering. Rocks having vertical strata are easily
loosened and broken down due to temperature changes, frost
action, water and wind action. The rocks having horizontal
strata are more compact and are less affected by the
mechanisms of disintegration and decomposition.
B) The gradient of the slope: The rocks in the region of steep
hillslope are easily disintegrated due to mechanical
weathering and the weathering materials are moved down in
the form of rock fall, debris fall etc and expose for further
weathering. The regions of gentle and moderate ground
slope are less affected by mechanical disintegration.
5.
6.
7.
8. C) Climate:
The greater the amount
of rainfall the higher the
rate of chemical
weathering.
Temperature changes
accelerate the rate of
mechanical weathering.
Seasonal variations in
climate generate
different conditions for
weathering.
In monsoon climate
rocks are subjected to
mechanical
disintegration due to hot
and dry summer months
whereas chemical and
biological weathering is
more dominant during
wet monsoon months.
9. D) Vegetation cover : Vegetation bind the rocks through roots and thus
protect them from weathering and erosion but the same time the
penetration of roots weakens the rocks by breaking them into several
blocks. Dense vegetations protect the ground surface from the direct
sun rays. The micro-organisms associated with the roots encourage
decomposition and disintegration of rocks through physico-
biochemical weathering.
– Time
– Man's activities
• There are three types of weathering agents:
• 1. Physical or mechanical weathering agents
• (i) moisture and water
• (ii) Frost
• (II) Insolation (temperature)
• (iv) Wind
• 2. Chemical weathering agents
• (I) Oxygen
• (II) Carbon dioxide
10.
11. • (III) Hydrogen
• 3. Biological weathering agents
• (I) vegetations
• (II) animals mainly microorganisms.
A. Physical or mechanical weathering: The physical or mechanical
weathering leads to fragmentation and breakdown of rock masses
into big blocks and boulders, cobbles and pebbles, sands and silts.
1. Block disintegration due to temperature:
Thermal stress weathering (sometimes called insolation
weathering)results from expansion or contraction of rock, caused
by temperature changes.
Some rocks are less affected by temperature changes such as
clastic sedimentary rocks (shales, sandstones) because the
particles are separated by thin cementing laminae of silica.
On the other hand, crystalline rocks, like granites are affected by
temperature changes as particles are closely associated with each
other and these particles expand and contract with increase and
decrease of temperature respectively.
13. • If temp. of granite rocks is increased by 65.5 degree C, the rock
expands by 2.54cm per 30.48 m distance. The repetition of
expansion and contraction of outer rock layers due to diurnal
range of temperature in the hot desert areas causes tension and
stresses which introduce parallel joints in the rocks. The rocks,
then, are disintegrated along these joints and broken big blocks
of rocks are dislodged from the main rock mass and fall down
the slope under the impact of gravity.
14. 2. Granular disintegration due to temperature:
The coarse-grained rocks are more affected by shattering process in
those hot deserts which are characterised by high range of daily
temperature. If the rocks are coarse-grained and are of different
colors they absorb insolation differently. And thus different parts of
the same rocks are affected by differential expansion and contraction
which causes stresses within the rocks due to which they are
disintegrated into smaller particles. Marble is an example.
15. 3. Block disintegration due to frost:
This process is more active in those areas which are very
often characterised by alternate process of freezing and
thawing of water mainly during night and day respectively.
The more compact and highly consolidated rocks (granites)
are less affected by freeze-thaw actions while less compact
loosely consolidated rocks (sedimentary) are more affected
by frost actions. Water present in between particles of
porous rocks freezes during night due to fall of temperature
below freezing points and thus expands due to increase in
temp. during day time. 10% thaws during day time and
contracts by 10% due to freezing. This diurnal freeze and
thaw cycle causes alternate expansion and contraction
which introduce tension and stresses due to which rocks
are disintegrated into smaller particles.
16. An example of rocks susceptible to frost action is chalk, which
has many pore spaces for the growth of ice crystals. When water
that has entered the joints freezes, the ice formed strains the
walls of the joints and causes the joints to deepen and widen.
When the ice thaws, water can flow further into the rock.
Repeated freeze-thaw cycles weaken the rocks which, over time,
break up along the joints into angular pieces.
17. 4. Exfoliation due to temperature and wind:
It occurs in places like hot deserts where the day temperature
often soars to 40 degrees Celsius and night temperature falls
to below 10 degrees Celsius. The repeated heating by day and
cooling by night cause the outer layers of the rock to expand
and contract alternately. Stress is created in the rock,
producing cracks and gradually, the outer layers of rock will
peel off.
It is also known as onion weathering, refers to peeling off
concentric shells of rocks due to combined actions of heat and
wind in hot arid and semi-arid regions and monsoon lands. It is
more common over crystalline rocks. The outer shells of rocks
become loose due to high temperature during day time and
comparatively low temp. during night respectively and these
loosened shells are removed (peeled off) by strong winds.
18. In pressure release, also known as unloading, overlying materials
(not necessarily rocks) are removed (by erosion, or other
processes), which causes underlying rocks to expand and fracture
parallel to the surface. Often the overlying material is heavy, and
the underlying rocks experience high pressure under them, for
example, a moving glacier. Pressure release may also cause
exfoliation to occur.
Pressure Release of
granite.
19.
20. 5. Salt wedging: As water enters the holes and cracks in the
surface of rocks, it often carries salt with it. As the water later
evaporates, the salt is left behind. Over time, these salt
deposits build up, creating pressure that can cause rocks to
split and weaken.
21. • Chemical weathering is the process by which rocks are
decomposed, dissolved or loosened by chemical processes to form
residual materials. Some of the processes involved in chemical
weathering are given below :
• CARBONATION process by which dissolved carbon dioxide in
rainwater or moisture in surrounding air forms carbonic acid and
reacts with the minerals in the rock. This process weakens the rock
thus breaking it down in the process.
• e.g.: Calcium Carbonate + Water + Carbon Dioxide ---> Calcium
Carbonate (soluble-easily dissolved)
• HYDROLYSIS
• chemical reaction between the minerals in the rock and hydrogen in
rain water. For example, during hydrolysis, the feldspar in granite
changes to clay mineral which crumbles easily, weakening the rock
and causing it to break down.
• OXIDATION The process by which oxygen combine with water and
minerals in the rock such as calcium and magnesium. When iron
reacts with oxygen, reddish -brown iron oxide is formed. The iron-
oxide crust crumbles easily and weakens the rock.
• e.g. : Iron + Oxygen --> Iron Oxide (crumbles)
•
22. • Comparison of unweathered
(left) and weathered (right)
limestone
•Oxidize pyrite cubes
23. SOLUTION process by which minerals in the rocks dissolve
directly in water.
• HYDRATION process where minerals in the rock absorb water
and expand, creating stress which causes the disintegration of
rocks.
• EG: Unhydrated Calcium sulphate + Water --> Hydrated Calcium
Sulphate (expands)
24. • Biological weathering is a form of weathering caused by the
activities of living organisms – for example, the growth of
roots or the burrowing of animals. Tree roots are probably
the most significant agents of biological weathering as they
are capable of prising apart rocks by growing into cracks and
joints. Plants also give off organic acids that help to break
down rocks chemically
Biological weathering of lava by
lichen, La Palma