SlideShare a Scribd company logo
1 of 48
Paleomagnetism
Paleomagnetism
Paleomagnetism
Paleomagnetism
• 1950’s: discovery of
ancient rocks had
magnetic directions
and inclinations that
did not correspond
with the present
magnetic pole position.
Rejection of Continental Drift
• Wegener concentrated on developing evidence that continents
had drifted not on what caused them to move.
• Two alternative possibilities
1.Continents plow their way through oceanic crust, shoving
it aside as a ship plows through water.
2.Continental crust slides over oceanic crust.
• Physicists proved that both mechanisms were impossible.
1.Oceanic crust is too strong for continents to plow through
it.
2.Frictional resistance is too great for continents to slide over
oceanic crust.
Seafloor Spreading Theory
HESS – DIETZ HYPOTHESIS
Sea-Floor Spreading
Mid-Ocean Ridge – the longest chain of mountains in
the world---these are divergent plate boundaries.
During World War
II, geologist Harry
Hess became
interested in
mapping the ocean
floor using sonar.
Sonar - a device that
bounces sound waves
off under-water objects
and then records the
echoes of these sound
waves.
The time it takes for the
echo to arrive indicates
the distance to the
object.
Unexpected Finding:
Long mountain ranges existed
throughout the floors of the
oceans called mid-ocean
ridges.
The longest one runs through
the middle of the Atlantic
Ocean and is called the Mid
Atlantic Ridge (MAR).
Hess devised a theory
called sea-floor
spreading which states
that at mid-ocean
ridges, molten material
rises from the mantle
and erupts. It then
spreads out, pushing
older rock to both sides
of the ridge.
THE PROOF-----SEAFLOOR SPREADING
•An American scientist named Harry Hess
proposed the seafloor spreading theory in
1962.
•The Sea floor spreading theory states that
new ocean crust is being created at mid-
ocean ridges (which are large mountain
chains underwater) and destroyed at deep-
sea trenches.
•This is proof that the plates are moving
along on a “conveyor belt” so Wegner’s
idea on continent drift was correct.
• Ocean floor moves like a conveyor belt carrying
continents with it.
• New ocean floor forms along cracks in the ocean crust
as molten material erupts from the mantle spreading
out and pushing older rocks to the sides of the crack.
New ocean floor is continually added by the process of
sea-floor spreading.
PROOF THATTHE SEA FLOOR IS SPREADING
1. The oldest ocean floor rocks ever found are 180
million years old. Remember the Earth is 4.6 billion
years old. This proves that ocean floor is being
destroyed therefore all ocean floor rocks are young
compared to the age of Earth.
2. The rocks closest to the ocean ridge were younger
than the rocks found further from the ridge. This
means that new rocks are formed at the ridges and
push the older rocks away from the ridge.
1. Evidence from Molten
Material
– Rocks shaped like
pillows(rock pillows)
show that molten
material has erupted
again and again from
cracks along the mid-
ocean ridge and cooled
quickly
Three Types of Evidences:
Molten Material
• Scientist aboard a
submersible called
Alvin dove to the
sea floor and
discovered rocks
called pillow lavas
along the mid
ocean ridges. Such
rocks can only
form from cooled
molten material.
• How does magnetic stripes support
the theory of Sea floor spreading?
2. Evidence from
Magnetic Stripes
2. Evidence from
Magnetic Stripes
– Rocks that make
up the ocean floor
lie in a pattern of
magnetized stripes
which hold a
record of the
reversals in
Earth’s magnetic
field
In Order to understand Magnetic
Stripes lets talk about the Earth’s
magnetic North!
What exactly is the North Pole?
The Earth acts like a giant magnet because of it’s
metallic core!
Magnetic Reversal
– a change in Earth’s magnetic field in which the north
magnetic pole becomes the south magnetic pole and vice
versa; has occurred on average every 500,000 years over
the past 65 million years.
• Normal Magnetic Polarity – magnetic orientation the
same as that of Earth’s current field.
• Reversed Magnetic Polarity – magnetic orientations in
rock that are opposite to the current orientation of
Earth’s magnetic field.
Magnetic Stripes
• Rocks that make up the ocean floor lie in a pattern of
magnetized stripes, which show a record of reversals of
Earth’s magnetic field.
How the seafloor got it’s stripes!
Magnetic Reversals occur
• When magma cools, the iron cools into the mineral magnetite. It lines up parallel to the Earth’s
present magnetic field. This iron is like compass needles, pointing north. So when the rock hardens,
a record of the Earth’s magnetic field at that time is locked in stone.
2. Studies of these magma flows have showed a
magnetic reversal over geologic time.
3. A magnetic reversal (called a FLIP) is a change in
Earth’s magnetic field. North pole becomes south pole
and south becomes north.
4. A magnetic field that has the same orientation as
Earth’s present field is said to have a normal polarity
5. A magnetic field that is opposite to the present field
has reversed polarity
3. Evidence from
Drilling Samples
– Core samples from
the ocean floor show
that older rocks are
found farther from
the ridge; youngest
rocks are in the
center of the ridge.
Drilling Samples
• In the year 1968, a drilling ship called the Glomar
Challenger was used to gather samples of rocks
from the ocean floor.
Scientists discovered that the further the rocks were from
the mid ocean ridges, the older they were. The youngest
rocks were always at the center of the ridges.
Resulting Question: Are all of the oceans getting
bigger?
• Suggested Answer: Ocean floors do not keep
spreading. Parts of the oceanic crust get plunged
into deep-ocean trenches due to the process of
subduction
Sea-Floor Spreading
Subduction – Process
by which the ocean
floor sinks beneath a
deep-ocean trench
and back into the
mantle; allows part of
the ocean floor to
sink back into the
mantle
Subduction-process by which the ocean floor sinks
beneath a deep-ocean trench and back into the
mantle.
Subduction in the Pacific Ocean:
There are many trenches, so the Pacific Ocean
is getting smaller.
Subduction in the
Atlantic Ocean:
There are fewer
trenches, so the
Atlantic Ocean is
getting wider.
The force responsible for driving or moving the plates is
_____________________.
Convection Currents occur within the mantle of the earth when
hot magma rises and cool magma sinks
convection currents
•Magma, because it is hotter and less
dense, is forced up towards the ocean floor
cooling off when it touches water.
•When the magma hardens, a small amount
of new ocean floor is added to the Earth’s
crust. As more magma rises and cools it
pushes the new sea floor away from the
ridge. This process is called sea floor
spreading.
Sea-Floor Spreading: Subduction
zone
Deep-Ocean
Trench – Occurs
at subduction
zones. Deep
underwater
canyons form
where oceanic
crust bends
downward
Subduction Zone
YOU NEED TO LOOK AT THE ARROWS AND
LEARN HOW
TO READ THEM FOR PLATE MOVEMENT
→← CONVERGING
←→ DIVERGING
↑↓SLIDING PAST
AMAZING EARTH SCIENCE FACTS
1. ____________________is created at mid oceanic ridges.
2. Age of rock ____________ as distance from ridge increases (____________ rock is at the ridge).
New sea floor
increases
youngest
3. __________________________
__________drive plate movement.
Convection
currents
Seafloor spreading theory discuss 3

More Related Content

What's hot

Grade 10 _Plate Tectonics2_Science10.ppt
Grade 10 _Plate Tectonics2_Science10.pptGrade 10 _Plate Tectonics2_Science10.ppt
Grade 10 _Plate Tectonics2_Science10.pptErlenaMirador1
 
Convection Currents
Convection CurrentsConvection Currents
Convection Currentsbgriesmer
 
Evidence of plate tectonics
Evidence of plate tectonicsEvidence of plate tectonics
Evidence of plate tectonicsSSpencer53
 
Sea floor spreading
Sea floor spreadingSea floor spreading
Sea floor spreadingShah Naseer
 
SCIENCE Grade 10: Continental Drift Theory
SCIENCE Grade 10: Continental Drift TheorySCIENCE Grade 10: Continental Drift Theory
SCIENCE Grade 10: Continental Drift TheoryPaula Marie Llido
 
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)DARYL (MONKAYO NHS)
 
Divergent plate boundaries
Divergent plate boundariesDivergent plate boundaries
Divergent plate boundariesNigina98
 
Plates and list of all major and minor plates in the world
Plates and list of all major and minor plates in the worldPlates and list of all major and minor plates in the world
Plates and list of all major and minor plates in the worldTahsin Islam Ornee
 
Platetectonics theory
Platetectonics theoryPlatetectonics theory
Platetectonics theoryanayamalik18
 
Transform Plate Boundaries
Transform Plate BoundariesTransform Plate Boundaries
Transform Plate BoundariesShirleykaHector
 
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIES
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIESPROCESSES AND LANDFORMS ALONG PLATE BOUNDARIES
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIESRolly Franco
 
Plate Movements Ppt
Plate Movements PptPlate Movements Ppt
Plate Movements PptPallavi Jha
 

What's hot (20)

Module 2: Earth's Interior
Module 2: Earth's InteriorModule 2: Earth's Interior
Module 2: Earth's Interior
 
Grade 10 _Plate Tectonics2_Science10.ppt
Grade 10 _Plate Tectonics2_Science10.pptGrade 10 _Plate Tectonics2_Science10.ppt
Grade 10 _Plate Tectonics2_Science10.ppt
 
Convection Currents
Convection CurrentsConvection Currents
Convection Currents
 
Evidence of plate tectonics
Evidence of plate tectonicsEvidence of plate tectonics
Evidence of plate tectonics
 
Divergent plate boundary PPT
Divergent plate boundary PPTDivergent plate boundary PPT
Divergent plate boundary PPT
 
Q1M6 POOSIBLE CAUSES of Plate movements.pptx
Q1M6 POOSIBLE CAUSES of Plate movements.pptxQ1M6 POOSIBLE CAUSES of Plate movements.pptx
Q1M6 POOSIBLE CAUSES of Plate movements.pptx
 
Sea floor spreading
Sea floor spreadingSea floor spreading
Sea floor spreading
 
SCIENCE Grade 10: Continental Drift Theory
SCIENCE Grade 10: Continental Drift TheorySCIENCE Grade 10: Continental Drift Theory
SCIENCE Grade 10: Continental Drift Theory
 
EARTH'S MECHANISM.pptx
EARTH'S MECHANISM.pptxEARTH'S MECHANISM.pptx
EARTH'S MECHANISM.pptx
 
Sea-Floor Spreading
Sea-Floor SpreadingSea-Floor Spreading
Sea-Floor Spreading
 
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)
PLATE TECTONICS(GRADE10SCIENCE 1STQUARTER MODULE1)
 
Plate Boundaries -Hot Spot
Plate Boundaries -Hot SpotPlate Boundaries -Hot Spot
Plate Boundaries -Hot Spot
 
Divergent plate boundaries
Divergent plate boundariesDivergent plate boundaries
Divergent plate boundaries
 
Plates and list of all major and minor plates in the world
Plates and list of all major and minor plates in the worldPlates and list of all major and minor plates in the world
Plates and list of all major and minor plates in the world
 
Platetectonics theory
Platetectonics theoryPlatetectonics theory
Platetectonics theory
 
Transform Plate Boundaries
Transform Plate BoundariesTransform Plate Boundaries
Transform Plate Boundaries
 
Grade 10 Science Quarter 1 Module 1
Grade 10 Science Quarter 1 Module 1Grade 10 Science Quarter 1 Module 1
Grade 10 Science Quarter 1 Module 1
 
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIES
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIESPROCESSES AND LANDFORMS ALONG PLATE BOUNDARIES
PROCESSES AND LANDFORMS ALONG PLATE BOUNDARIES
 
The seafloor spreading
The seafloor spreadingThe seafloor spreading
The seafloor spreading
 
Plate Movements Ppt
Plate Movements PptPlate Movements Ppt
Plate Movements Ppt
 

Viewers also liked

2.2 active faults & other earthquakes source zones
2.2 active faults & other earthquakes source zones2.2 active faults & other earthquakes source zones
2.2 active faults & other earthquakes source zonesMakati Science High School
 

Viewers also liked (20)

19. atmospheric processes 2
19. atmospheric processes 219. atmospheric processes 2
19. atmospheric processes 2
 
Seismic waveanimations braile copy
Seismic waveanimations braile copySeismic waveanimations braile copy
Seismic waveanimations braile copy
 
Latitude and longitude
Latitude and longitudeLatitude and longitude
Latitude and longitude
 
Atmosphere 1
Atmosphere 1Atmosphere 1
Atmosphere 1
 
Watershed
WatershedWatershed
Watershed
 
Continental drift theory discuss
Continental drift theory discussContinental drift theory discuss
Continental drift theory discuss
 
Module 2 intro
Module 2 introModule 2 intro
Module 2 intro
 
Types of PB act 3 6
Types of PB act 3 6Types of PB act 3 6
Types of PB act 3 6
 
Air masses
Air massesAir masses
Air masses
 
Atmosphere ghe
Atmosphere gheAtmosphere ghe
Atmosphere ghe
 
Phil vdeo proj.
Phil vdeo proj.Phil vdeo proj.
Phil vdeo proj.
 
Weathering, soil formation, and erosion ch7 8
Weathering, soil formation, and erosion ch7 8Weathering, soil formation, and erosion ch7 8
Weathering, soil formation, and erosion ch7 8
 
Weathering and soil formation
Weathering and soil formationWeathering and soil formation
Weathering and soil formation
 
Weathering and soil formation
Weathering and soil formationWeathering and soil formation
Weathering and soil formation
 
Weathering, soil formation, and erosion ch7 8
Weathering, soil formation, and erosion ch7 8Weathering, soil formation, and erosion ch7 8
Weathering, soil formation, and erosion ch7 8
 
Seafloor magnetic polarity 2
Seafloor  magnetic polarity 2Seafloor  magnetic polarity 2
Seafloor magnetic polarity 2
 
Overview of the phil minerals potential
Overview of the phil minerals potentialOverview of the phil minerals potential
Overview of the phil minerals potential
 
2.2 active faults & other earthquakes source zones
2.2 active faults & other earthquakes source zones2.2 active faults & other earthquakes source zones
2.2 active faults & other earthquakes source zones
 
Soil profile
Soil profileSoil profile
Soil profile
 
Soil and soil diversity
Soil and soil diversitySoil and soil diversity
Soil and soil diversity
 

Similar to Seafloor spreading theory discuss 3

CONTINENTAL DRIFT HYPOTHESIS
CONTINENTAL DRIFT HYPOTHESIS CONTINENTAL DRIFT HYPOTHESIS
CONTINENTAL DRIFT HYPOTHESIS THILAKAR MANI
 
Sea floor spreading
Sea floor spreadingSea floor spreading
Sea floor spreadingtagalog123
 
Sea-Floor Spreading Notes - Jenny
Sea-Floor Spreading Notes - JennySea-Floor Spreading Notes - Jenny
Sea-Floor Spreading Notes - JennyJenny Dixon
 
Plate Tectonics - Chapter 5
Plate Tectonics - Chapter 5Plate Tectonics - Chapter 5
Plate Tectonics - Chapter 5nilsona
 
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptx
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptxSEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptx
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptxAngelieZantua1
 
Earth science. Plate Tectonics ppt
Earth science. Plate Tectonics pptEarth science. Plate Tectonics ppt
Earth science. Plate Tectonics pptMrs. Henley
 
Study of plate tectonics of the earth, or plate movement,
Study of plate tectonics of the earth, or plate movement, Study of plate tectonics of the earth, or plate movement,
Study of plate tectonics of the earth, or plate movement, Jahangir Alam
 
2012 updated plate tectonics new one use this one backup
2012 updated plate tectonics new one use this one backup2012 updated plate tectonics new one use this one backup
2012 updated plate tectonics new one use this one backupharvey09
 
2013 updated plate tectonics new one use this one
2013 updated plate tectonics new one use this one2013 updated plate tectonics new one use this one
2013 updated plate tectonics new one use this oneharvey09
 
Lecture 2-The Dynamic Earth.pdf
Lecture 2-The Dynamic Earth.pdfLecture 2-The Dynamic Earth.pdf
Lecture 2-The Dynamic Earth.pdfMichael706438
 
Sea Floor Spreading Theory.ppt
Sea Floor Spreading Theory.pptSea Floor Spreading Theory.ppt
Sea Floor Spreading Theory.pptmikeebio1
 
PLATE TECTONICS.ppt.....................
PLATE TECTONICS.ppt.....................PLATE TECTONICS.ppt.....................
PLATE TECTONICS.ppt.....................vivialynasis
 
Continental Drift - Plate tectonic - Theory evidences.pptx
Continental Drift - Plate tectonic - Theory evidences.pptxContinental Drift - Plate tectonic - Theory evidences.pptx
Continental Drift - Plate tectonic - Theory evidences.pptxDrVenkatRaman1
 
Lecture20 nov25-bb
Lecture20 nov25-bbLecture20 nov25-bb
Lecture20 nov25-bbPeter Shiv
 
Chapter 3 Plate Tectonics
Chapter 3 Plate TectonicsChapter 3 Plate Tectonics
Chapter 3 Plate TectonicsTom Jenkins
 
Chapter 3 Plate Tectonics
Chapter 3 Plate TectonicsChapter 3 Plate Tectonics
Chapter 3 Plate TectonicsTom Jenkins
 

Similar to Seafloor spreading theory discuss 3 (20)

CONTINENTAL DRIFT HYPOTHESIS
CONTINENTAL DRIFT HYPOTHESIS CONTINENTAL DRIFT HYPOTHESIS
CONTINENTAL DRIFT HYPOTHESIS
 
Sea floor spreading
Sea floor spreadingSea floor spreading
Sea floor spreading
 
Sea-Floor Spreading Notes - Jenny
Sea-Floor Spreading Notes - JennySea-Floor Spreading Notes - Jenny
Sea-Floor Spreading Notes - Jenny
 
Plate tectonics unit
Plate tectonics unitPlate tectonics unit
Plate tectonics unit
 
Plate Tectonics - Chapter 5
Plate Tectonics - Chapter 5Plate Tectonics - Chapter 5
Plate Tectonics - Chapter 5
 
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptx
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptxSEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptx
SEA-FLOOR-SPREADING SEA-FLOOR-SPREADINGpptx
 
Plate Tectonics I
Plate Tectonics IPlate Tectonics I
Plate Tectonics I
 
Earth science. Plate Tectonics ppt
Earth science. Plate Tectonics pptEarth science. Plate Tectonics ppt
Earth science. Plate Tectonics ppt
 
Study of plate tectonics of the earth, or plate movement,
Study of plate tectonics of the earth, or plate movement, Study of plate tectonics of the earth, or plate movement,
Study of plate tectonics of the earth, or plate movement,
 
2012 updated plate tectonics new one use this one backup
2012 updated plate tectonics new one use this one backup2012 updated plate tectonics new one use this one backup
2012 updated plate tectonics new one use this one backup
 
2013 updated plate tectonics new one use this one
2013 updated plate tectonics new one use this one2013 updated plate tectonics new one use this one
2013 updated plate tectonics new one use this one
 
Lecture 2-The Dynamic Earth.pdf
Lecture 2-The Dynamic Earth.pdfLecture 2-The Dynamic Earth.pdf
Lecture 2-The Dynamic Earth.pdf
 
Plate tectonics
Plate tectonicsPlate tectonics
Plate tectonics
 
Sea Floor Spreading Theory.ppt
Sea Floor Spreading Theory.pptSea Floor Spreading Theory.ppt
Sea Floor Spreading Theory.ppt
 
PLATE TECTONICS.ppt.....................
PLATE TECTONICS.ppt.....................PLATE TECTONICS.ppt.....................
PLATE TECTONICS.ppt.....................
 
Continental Drift - Plate tectonic - Theory evidences.pptx
Continental Drift - Plate tectonic - Theory evidences.pptxContinental Drift - Plate tectonic - Theory evidences.pptx
Continental Drift - Plate tectonic - Theory evidences.pptx
 
Lecture20 nov25-bb
Lecture20 nov25-bbLecture20 nov25-bb
Lecture20 nov25-bb
 
Plate tectonics
Plate tectonicsPlate tectonics
Plate tectonics
 
Chapter 3 Plate Tectonics
Chapter 3 Plate TectonicsChapter 3 Plate Tectonics
Chapter 3 Plate Tectonics
 
Chapter 3 Plate Tectonics
Chapter 3 Plate TectonicsChapter 3 Plate Tectonics
Chapter 3 Plate Tectonics
 

More from Makati Science High School

Types of graphs and charts and their uses with examples and pics
Types of graphs and charts and their uses  with examples and picsTypes of graphs and charts and their uses  with examples and pics
Types of graphs and charts and their uses with examples and picsMakati Science High School
 

More from Makati Science High School (20)

Writing a Scientific Paper
Writing a Scientific PaperWriting a Scientific Paper
Writing a Scientific Paper
 
Research Paper Rubrics 2020
Research Paper Rubrics 2020Research Paper Rubrics 2020
Research Paper Rubrics 2020
 
Statistical test discuss 5
Statistical test discuss 5Statistical test discuss 5
Statistical test discuss 5
 
Measures of variation discuss 2.1
Measures of variation discuss  2.1Measures of variation discuss  2.1
Measures of variation discuss 2.1
 
Measures of dispersion discuss 2.2
Measures of dispersion discuss 2.2Measures of dispersion discuss 2.2
Measures of dispersion discuss 2.2
 
Materials and methods discuss
Materials and methods  discussMaterials and methods  discuss
Materials and methods discuss
 
Inferential stat tests samples discuss 4
Inferential stat tests samples discuss 4Inferential stat tests samples discuss 4
Inferential stat tests samples discuss 4
 
Ds vs Is discuss 3.1
Ds vs Is discuss 3.1Ds vs Is discuss 3.1
Ds vs Is discuss 3.1
 
Descriptive inferential-discuss 1
Descriptive  inferential-discuss 1Descriptive  inferential-discuss 1
Descriptive inferential-discuss 1
 
Central tendency m,m,m 1.2
Central tendency m,m,m 1.2Central tendency m,m,m 1.2
Central tendency m,m,m 1.2
 
Central tendency discuss 2
Central tendency  discuss 2Central tendency  discuss 2
Central tendency discuss 2
 
Types of graphs and charts and their uses with examples and pics
Types of graphs and charts and their uses  with examples and picsTypes of graphs and charts and their uses  with examples and pics
Types of graphs and charts and their uses with examples and pics
 
Levels of measurement discuss
Levels of measurement   discussLevels of measurement   discuss
Levels of measurement discuss
 
Gantt chart discuss 3
Gantt chart discuss 3Gantt chart discuss 3
Gantt chart discuss 3
 
Gantt chart discuss 2
Gantt chart discuss 2Gantt chart discuss 2
Gantt chart discuss 2
 
Gantt chart discuss 1
Gantt chart discuss 1Gantt chart discuss 1
Gantt chart discuss 1
 
Research Designs -9 experimental Designs
Research Designs -9 experimental DesignsResearch Designs -9 experimental Designs
Research Designs -9 experimental Designs
 
Research designs Pt 1
Research designs Pt 1Research designs Pt 1
Research designs Pt 1
 
Identifying variables
Identifying variablesIdentifying variables
Identifying variables
 
Kinds and classifications of research
Kinds and classifications of researchKinds and classifications of research
Kinds and classifications of research
 

Recently uploaded

Influencing policy (training slides from Fast Track Impact)
Influencing policy (training slides from Fast Track Impact)Influencing policy (training slides from Fast Track Impact)
Influencing policy (training slides from Fast Track Impact)Mark Reed
 
4.18.24 Movement Legacies, Reflection, and Review.pptx
4.18.24 Movement Legacies, Reflection, and Review.pptx4.18.24 Movement Legacies, Reflection, and Review.pptx
4.18.24 Movement Legacies, Reflection, and Review.pptxmary850239
 
Millenials and Fillennials (Ethical Challenge and Responses).pptx
Millenials and Fillennials (Ethical Challenge and Responses).pptxMillenials and Fillennials (Ethical Challenge and Responses).pptx
Millenials and Fillennials (Ethical Challenge and Responses).pptxJanEmmanBrigoli
 
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptxMULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptxAnupkumar Sharma
 
Measures of Position DECILES for ungrouped data
Measures of Position DECILES for ungrouped dataMeasures of Position DECILES for ungrouped data
Measures of Position DECILES for ungrouped dataBabyAnnMotar
 
Keynote by Prof. Wurzer at Nordex about IP-design
Keynote by Prof. Wurzer at Nordex about IP-designKeynote by Prof. Wurzer at Nordex about IP-design
Keynote by Prof. Wurzer at Nordex about IP-designMIPLM
 
Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Seán Kennedy
 
ROLES IN A STAGE PRODUCTION in arts.pptx
ROLES IN A STAGE PRODUCTION in arts.pptxROLES IN A STAGE PRODUCTION in arts.pptx
ROLES IN A STAGE PRODUCTION in arts.pptxVanesaIglesias10
 
Choosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for ParentsChoosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for Parentsnavabharathschool99
 
How to Add Barcode on PDF Report in Odoo 17
How to Add Barcode on PDF Report in Odoo 17How to Add Barcode on PDF Report in Odoo 17
How to Add Barcode on PDF Report in Odoo 17Celine George
 
Concurrency Control in Database Management system
Concurrency Control in Database Management systemConcurrency Control in Database Management system
Concurrency Control in Database Management systemChristalin Nelson
 
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)lakshayb543
 
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...Nguyen Thanh Tu Collection
 
Daily Lesson Plan in Mathematics Quarter 4
Daily Lesson Plan in Mathematics Quarter 4Daily Lesson Plan in Mathematics Quarter 4
Daily Lesson Plan in Mathematics Quarter 4JOYLYNSAMANIEGO
 
Transaction Management in Database Management System
Transaction Management in Database Management SystemTransaction Management in Database Management System
Transaction Management in Database Management SystemChristalin Nelson
 
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTS
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTSGRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTS
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTSJoshuaGantuangco2
 
Oppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmOppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmStan Meyer
 

Recently uploaded (20)

Paradigm shift in nursing research by RS MEHTA
Paradigm shift in nursing research by RS MEHTAParadigm shift in nursing research by RS MEHTA
Paradigm shift in nursing research by RS MEHTA
 
Influencing policy (training slides from Fast Track Impact)
Influencing policy (training slides from Fast Track Impact)Influencing policy (training slides from Fast Track Impact)
Influencing policy (training slides from Fast Track Impact)
 
4.18.24 Movement Legacies, Reflection, and Review.pptx
4.18.24 Movement Legacies, Reflection, and Review.pptx4.18.24 Movement Legacies, Reflection, and Review.pptx
4.18.24 Movement Legacies, Reflection, and Review.pptx
 
Millenials and Fillennials (Ethical Challenge and Responses).pptx
Millenials and Fillennials (Ethical Challenge and Responses).pptxMillenials and Fillennials (Ethical Challenge and Responses).pptx
Millenials and Fillennials (Ethical Challenge and Responses).pptx
 
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptxFINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
 
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptxMULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
 
Measures of Position DECILES for ungrouped data
Measures of Position DECILES for ungrouped dataMeasures of Position DECILES for ungrouped data
Measures of Position DECILES for ungrouped data
 
Keynote by Prof. Wurzer at Nordex about IP-design
Keynote by Prof. Wurzer at Nordex about IP-designKeynote by Prof. Wurzer at Nordex about IP-design
Keynote by Prof. Wurzer at Nordex about IP-design
 
Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...
 
ROLES IN A STAGE PRODUCTION in arts.pptx
ROLES IN A STAGE PRODUCTION in arts.pptxROLES IN A STAGE PRODUCTION in arts.pptx
ROLES IN A STAGE PRODUCTION in arts.pptx
 
Choosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for ParentsChoosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for Parents
 
How to Add Barcode on PDF Report in Odoo 17
How to Add Barcode on PDF Report in Odoo 17How to Add Barcode on PDF Report in Odoo 17
How to Add Barcode on PDF Report in Odoo 17
 
Concurrency Control in Database Management system
Concurrency Control in Database Management systemConcurrency Control in Database Management system
Concurrency Control in Database Management system
 
YOUVE GOT EMAIL_FINALS_EL_DORADO_2024.pptx
YOUVE GOT EMAIL_FINALS_EL_DORADO_2024.pptxYOUVE GOT EMAIL_FINALS_EL_DORADO_2024.pptx
YOUVE GOT EMAIL_FINALS_EL_DORADO_2024.pptx
 
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
 
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
 
Daily Lesson Plan in Mathematics Quarter 4
Daily Lesson Plan in Mathematics Quarter 4Daily Lesson Plan in Mathematics Quarter 4
Daily Lesson Plan in Mathematics Quarter 4
 
Transaction Management in Database Management System
Transaction Management in Database Management SystemTransaction Management in Database Management System
Transaction Management in Database Management System
 
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTS
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTSGRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTS
GRADE 4 - SUMMATIVE TEST QUARTER 4 ALL SUBJECTS
 
Oppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmOppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and Film
 

Seafloor spreading theory discuss 3

  • 4. Paleomagnetism • 1950’s: discovery of ancient rocks had magnetic directions and inclinations that did not correspond with the present magnetic pole position.
  • 5. Rejection of Continental Drift • Wegener concentrated on developing evidence that continents had drifted not on what caused them to move. • Two alternative possibilities 1.Continents plow their way through oceanic crust, shoving it aside as a ship plows through water. 2.Continental crust slides over oceanic crust. • Physicists proved that both mechanisms were impossible. 1.Oceanic crust is too strong for continents to plow through it. 2.Frictional resistance is too great for continents to slide over oceanic crust.
  • 6. Seafloor Spreading Theory HESS – DIETZ HYPOTHESIS
  • 8.
  • 9. Mid-Ocean Ridge – the longest chain of mountains in the world---these are divergent plate boundaries.
  • 10. During World War II, geologist Harry Hess became interested in mapping the ocean floor using sonar.
  • 11. Sonar - a device that bounces sound waves off under-water objects and then records the echoes of these sound waves. The time it takes for the echo to arrive indicates the distance to the object.
  • 12. Unexpected Finding: Long mountain ranges existed throughout the floors of the oceans called mid-ocean ridges. The longest one runs through the middle of the Atlantic Ocean and is called the Mid Atlantic Ridge (MAR).
  • 13. Hess devised a theory called sea-floor spreading which states that at mid-ocean ridges, molten material rises from the mantle and erupts. It then spreads out, pushing older rock to both sides of the ridge.
  • 14. THE PROOF-----SEAFLOOR SPREADING •An American scientist named Harry Hess proposed the seafloor spreading theory in 1962. •The Sea floor spreading theory states that new ocean crust is being created at mid- ocean ridges (which are large mountain chains underwater) and destroyed at deep- sea trenches. •This is proof that the plates are moving along on a “conveyor belt” so Wegner’s idea on continent drift was correct.
  • 15. • Ocean floor moves like a conveyor belt carrying continents with it. • New ocean floor forms along cracks in the ocean crust as molten material erupts from the mantle spreading out and pushing older rocks to the sides of the crack. New ocean floor is continually added by the process of sea-floor spreading.
  • 16. PROOF THATTHE SEA FLOOR IS SPREADING 1. The oldest ocean floor rocks ever found are 180 million years old. Remember the Earth is 4.6 billion years old. This proves that ocean floor is being destroyed therefore all ocean floor rocks are young compared to the age of Earth. 2. The rocks closest to the ocean ridge were younger than the rocks found further from the ridge. This means that new rocks are formed at the ridges and push the older rocks away from the ridge.
  • 17. 1. Evidence from Molten Material – Rocks shaped like pillows(rock pillows) show that molten material has erupted again and again from cracks along the mid- ocean ridge and cooled quickly Three Types of Evidences:
  • 18. Molten Material • Scientist aboard a submersible called Alvin dove to the sea floor and discovered rocks called pillow lavas along the mid ocean ridges. Such rocks can only form from cooled molten material.
  • 19.
  • 20. • How does magnetic stripes support the theory of Sea floor spreading? 2. Evidence from Magnetic Stripes
  • 21. 2. Evidence from Magnetic Stripes – Rocks that make up the ocean floor lie in a pattern of magnetized stripes which hold a record of the reversals in Earth’s magnetic field
  • 22. In Order to understand Magnetic Stripes lets talk about the Earth’s magnetic North!
  • 23. What exactly is the North Pole?
  • 24. The Earth acts like a giant magnet because of it’s metallic core!
  • 25. Magnetic Reversal – a change in Earth’s magnetic field in which the north magnetic pole becomes the south magnetic pole and vice versa; has occurred on average every 500,000 years over the past 65 million years. • Normal Magnetic Polarity – magnetic orientation the same as that of Earth’s current field. • Reversed Magnetic Polarity – magnetic orientations in rock that are opposite to the current orientation of Earth’s magnetic field.
  • 26. Magnetic Stripes • Rocks that make up the ocean floor lie in a pattern of magnetized stripes, which show a record of reversals of Earth’s magnetic field.
  • 27.
  • 28. How the seafloor got it’s stripes!
  • 29.
  • 30.
  • 31. Magnetic Reversals occur • When magma cools, the iron cools into the mineral magnetite. It lines up parallel to the Earth’s present magnetic field. This iron is like compass needles, pointing north. So when the rock hardens, a record of the Earth’s magnetic field at that time is locked in stone.
  • 32. 2. Studies of these magma flows have showed a magnetic reversal over geologic time. 3. A magnetic reversal (called a FLIP) is a change in Earth’s magnetic field. North pole becomes south pole and south becomes north.
  • 33. 4. A magnetic field that has the same orientation as Earth’s present field is said to have a normal polarity 5. A magnetic field that is opposite to the present field has reversed polarity
  • 34. 3. Evidence from Drilling Samples – Core samples from the ocean floor show that older rocks are found farther from the ridge; youngest rocks are in the center of the ridge.
  • 35. Drilling Samples • In the year 1968, a drilling ship called the Glomar Challenger was used to gather samples of rocks from the ocean floor.
  • 36. Scientists discovered that the further the rocks were from the mid ocean ridges, the older they were. The youngest rocks were always at the center of the ridges.
  • 37. Resulting Question: Are all of the oceans getting bigger? • Suggested Answer: Ocean floors do not keep spreading. Parts of the oceanic crust get plunged into deep-ocean trenches due to the process of subduction
  • 38. Sea-Floor Spreading Subduction – Process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle; allows part of the ocean floor to sink back into the mantle
  • 39. Subduction-process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle.
  • 40. Subduction in the Pacific Ocean: There are many trenches, so the Pacific Ocean is getting smaller. Subduction in the Atlantic Ocean: There are fewer trenches, so the Atlantic Ocean is getting wider.
  • 41.
  • 42. The force responsible for driving or moving the plates is _____________________. Convection Currents occur within the mantle of the earth when hot magma rises and cool magma sinks convection currents
  • 43. •Magma, because it is hotter and less dense, is forced up towards the ocean floor cooling off when it touches water. •When the magma hardens, a small amount of new ocean floor is added to the Earth’s crust. As more magma rises and cools it pushes the new sea floor away from the ridge. This process is called sea floor spreading.
  • 44. Sea-Floor Spreading: Subduction zone Deep-Ocean Trench – Occurs at subduction zones. Deep underwater canyons form where oceanic crust bends downward
  • 46. YOU NEED TO LOOK AT THE ARROWS AND LEARN HOW TO READ THEM FOR PLATE MOVEMENT →← CONVERGING ←→ DIVERGING ↑↓SLIDING PAST
  • 47. AMAZING EARTH SCIENCE FACTS 1. ____________________is created at mid oceanic ridges. 2. Age of rock ____________ as distance from ridge increases (____________ rock is at the ridge). New sea floor increases youngest 3. __________________________ __________drive plate movement. Convection currents

Editor's Notes

  1. By Harry Hess and Robert Dietz The earth’s seafloor is formed in a cycle a new seafloor crust are made in the ridges and older seafloor crust is pushed towards/ destroyed in the trenches.
  2. Shortly after World War II, scientist began to explore the floors of the Earth’s oceans. Initially undertaken for military – defense strategists wanted a detailed knowledge of sea floor topography for submarine warfare economic reasons – to lay undersea telephone cables.
  3. sound navigation ranging, after radar
  4. Earth’s magnetic field reversed itself from time to time in the past – reason is not clear