A PowerPoint Presentation for Grade 9 teachers. This presentation is ONLY suggested guide for teachers to assist them on the discussion after the activities as suggested in the Learner's Module were performed. Please feel free to add comments and suggestions. Thanks!
Study of plate tectonics of the earth, or plate movement, Jahangir Alam
a) Wegener’s Evidence (Continental Drift)
b) History of Plate Tectonics
c) Breakup and Appearence of Pangea
WHAT IS A PLATE?
Major continental and oceanic plates include:
Types of Earth’s Crust:
Plate tectonics (from the Late Latin tectonicus) is a scientific theory which describes the large scale motions of Earth's lithosphere.
THE DYNAMIC EARTH:
The earth is a dynamic planet, continuously changing both externally and internally. The earth’s surface is constantly being changed by endo-genetic processes resulting in volcanism and tectonism, and exogenetic processes such as erosion and deposition. These processes have been active throughout geological history. The processes that change the surface feature are normally very slow (erosion and deposition) except some catastrophic changes that occur instantaneously as in the case of volcanism or earthquakes. The interior of the earth is also in motion. Deeper inside the earth, the liquid core probably flows at a geologically rapid rate of a few tenths of mm/s. Several hypotheses attempted to explain the dynamism of the earth.
+ Horizontal movement hypothesis
+ Continental drift, displacement hypothesis
Development of the plate tectonic theory.
Plate tectonic theory arose out of the hypothesis of continental drift proposed by Alfred Wegener in 1912. He suggested that the present continents once formed a single land mass that drifted apart, thus releasing the continents from the Earth's core and likening them to "icebergs" of low density granite floating on a sea of denser basalt.
Seafloor Spreading
The first evidence that the lithospheric plates did move came with the discovery of variable magnetic field direction in rocks of differing ages.
Rigid Earth Theory. Plasticity. Isostacy. Alfred Wegener and Continental Drift. Wegener's lines of evidence. Harry Hess and more evidence. Power source = convection currents in the mantle. Theory of Plate Tectonics. Plate boundaries: Divergent (spreading centers), Convergent (subduction zones), Lateral (transform faults). Three types of subduction zones. Hot spots. Accreted Terranes. Cratons. Continental Shields. Topography. (maps for lab)
Steps to Plate TectonicsStep 1 – Continental Driftwww.mat.docxdessiechisomjj4
Steps to Plate Tectonics:
Step 1 – Continental Drift
www.math.montana.edu / ~nmp / materials / ess / geosphere / inter / activities / plate_calc / pangaea_map.gif
The Continental Drift hypothesis published by Alfred Wegener in his 1915 book “ The Origin of Continents and Oceans”, although this was partially based on the work of earlier investigators.
Continental Drift = the continents were once connected in a single supercontinent called Pangaea. They have since drifted apart and are still moving today.
http://www.kidsgeo.com/geology-for-kids/0042-pangaea.php
Wegener’s hypothesis had several problems:
1) He had no power source – no way to make the continents move.
2) He thought the continents moved through the seafloor just like boats move through the ocean, but there was no evidence of this (no wake)
3) He was a meteorologist so many geologists didn’t take him seriously!
BUT Wegener had lots of evidence to show that the continents were once connected!
1) The jigsaw puzzle-like fit of the continents.
Figure 2.3 in text
Identical fossil assemblages on now widely spaced continents!
best about 250-200 MY ago
become increasingly dissimilar the closer to today we look!
Garrison, 2012, Essentials of Oceanography
3) Sequences of similar rock types on continents which do not now have the same geologic environment!
http://www.geology.ohio-state.edu/~vonfrese/gs100/lect25/index.html
4) Geologic structures (mountain ranges, faults, chains of volcanoes) which match up on either side of oceans but can not be found underwater.
5) Apparent polar wander – paleoclimatic evidence the continents had very different climates 250 MY ago than they do today.
either the continents moved or
the climate bands moved – which means the Earth’s poles of rotation moved.
Earth’s climate zones today are arranged symmetrically around the poles.
http://www.webquest.hawaii.edu/kahihi/sciencedictionary/C/climatezone.php
Paleoclimatic data from ˶300 MY ago, figure 2.5 in text
After Wegener died, his ideas were largely dismissed, until…
Post-Wegener evidence for drifting continents (and plate tectonics)…
6) Apparent Polar Wander – Paleomagnetic evidence.
Figure 2.7 showing that the Earth has a magnetic field very similar to that created by a bar magnet.
Directions of magnets parallel to Earth’s magnetic field lines.
Post-Wegener evidence for drifting continents (and plate tectonics)…
Figure 2.7b showing how magnets align to the Earth’s magnetic field when allowed to move freely.
Rocks containing the mineral magnetite (especially basalt) record the orientation of the Earth’s magnetic field at the time the rocks formed.
Figure 2.8a showing apparent polar wander paths for Europe and North America.
Figure 2.8b showing alignment of polar wander curves if the Atlantic Ocean is “closed”
The polar wander tracks for all the continents show great variation, suggesting it is the continents that moved!
If we put the continents “back to.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
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.
3. 9.1 Continental Drift Wegener’s continental drift hypothesis stated that the continents had once been joined to form a single supercontinent. • Wegener proposed that the supercontinent, Pangaea, began to break apart 200 million years ago and form the present landmasses. An Idea Before Its Time
5. 9.1 Continental Drift Evidence • The Continental Puzzle • Matching Fossils - Fossil evidence for continental drift includes several fossil organisms found on different landmasses. An Idea Before Its Time
6. 9.1 Continental Drift Evidence • Ancient Climates • Rock Types and Structures - Rock evidence for continental exists in the form of several mountain belts that end at one coastline, only to reappear on a landmass across the ocean. An Idea Before Its Time
9. 9.1 Continental Drift A New Theory Emerges • Wegener could not provide an explanation of exactly what made the continents move. News technology lead to findings which then lead to a new theory called plate tectonics. Rejecting the Hypothesis
10. 9.2 Plate Tectonics According to the plate tectonics theory, the uppermost mantle, along with the overlying crust, behaves as a strong, rigid layer. This layer is known as the lithosphere. • A plate is one of numerous rigid sections of the lithosphere that move as a unit over the material of the asthenosphere. Earth’s Major Roles
11. 9.2 Plate Tectonics Divergent boundaries (also called spreading centers) are the place where two plates move apart. Convergent boundaries form where two plates move together. Transform fault boundaries are margins where two plates grind past each other without the production or destruction of the lithosphere. Types of Plate Boundaries
13. 9.3 Actions at Plate Boundaries Oceanic Ridges and Seafloor Spreading • Oceanic ridges are continuous elevated zones on the floor of all major ocean basins. The rifts at the crest of ridges represent divergent plate boundaries. • Rift valleys are deep faulted structures found along the axes of divergent plate boundaries. They can develop on the seafloor or on land. • Seafloor spreading produces new oceanic lithosphere. Divergent Boundaries
15. 9.3 Actions at Plate Boundaries Continental Rifts • When spreading centers develop within a continent, the landmass may split into two or more smaller segments, forming a rift. Divergent Boundaries
17. 9.3 Actions at Plate Boundaries A subduction zone occurs when one oceanic plate is forced down into the mantle beneath a second plate. • Denser oceanic slab sinks into the asthenosphere. Oceanic-Continental • Pockets of magma develop and rise. • Continental volcanic arcs form in part by volcanic activity caused by the subduction o f oceanic lithosphere beneath a continent. • Examples include the Andes, Cascades, and the Sierra Nevadas. Convergent Boundaries
19. 9.3 Actions at Plate Boundaries • Two oceanic slabs converge and one descends beneath the other. Oceanic-Oceanic • This kind of boundary often forms volcanoes on the ocean floor. • Volcanic island arcs form as volcanoes emerge from the sea. • Examples include the Aleutian, Mariana, and Tonga islands. Convergent Boundaries
21. 9.3 Actions at Plate Boundaries • When subducting plates contain continental material, two continents collide. Continental-Continental • This kind of boundary can produce new mountain ranges, such as the Himalayas. Convergent Boundaries
24. 9.3 Actions at Plate Boundaries At a transform fault boundary, plates grind past each other without destroying the lithosphere. Transform faults • Most join two segments of a mid-ocean ridge. • At the time of formation, they roughly parallel the direction of plate movement. • They aid the movement of oceanic crustal material. Transform Fault Boundaries
28. 9.4 Testing Plate Tectonics The discovery of strips of alternating polarity, which lie as mirror images across the ocean ridges, is among the strongest evidence of seafloor spreading. Evidence for Plate Tectonics
