This document discusses key evidence for plate tectonics including matching fossils, rocks, and climate patterns found in different parts of the world. It describes plate boundaries like divergent boundaries where new crust forms at mid-ocean ridges, and convergent boundaries where plates collide including ocean-ocean, ocean-continent, and continent-continent collisions. It also discusses mantle plumes and hotspot volcanism. The key takeaways are that convection currents in the mantle drive plate motions, there are three main types of plate boundaries with different associated features and hazards, and hotspots represent fixed mantle plumes unrelated to boundaries.
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)
This pdf covers theory of continental drift and plate tectonics.
Continental drift
Plate Tectonics
Mantle Convection
Convection currects
Types of Mantle convection
Drivers of the plate motion.
Bibliography_ Lutgens, Tarbuk and Tasa Publisher: Prentice Hall
A great landmass which was thought to be in the geological past, splitting into fragments drifting apart and again colliding into one another is called a supercontinent.1. VAALBARA -First ever made continent was Vaalbara which was 3.6 billion years old, it was named after kaapvaal and Pilbara which were the most ancient cratons present on that land mass. Kaapvaal is in Africa and Pilbara is in western Australia.2. UR- A supercontinent which was 3000 m.y.a and it was smaller than modern day Australia.3. KENORLAND- 2700 m.y.a famous events were HURONIAN GLACIATION. Also known as SNOWBALL EARTH.Responsible for formation of phytoplanktons.and VREDEFORT impact.4. COLUMBIA- Also called as NUNA . Period between Snowball Earth and subsequent Oxidation is called as THE BARREN BILLION.5. RODINIA- 1130 m.y.a.SECOND SNOWBALL EARTH.Also known as NEOPROTEROZOIC GLACIATION.6. PANNOTIA- 750 m.y.aThe formation of Pannotia was associated with the breakup of Rodinia into Proto- Gondwana and Proto-Laurasia. Two oceans were PANTHALSSA and Pan-African Ocean.7. PANGEA- One of the Youngest Supercontinent of all time , there are plenty of evidences of this Supercontinent. Like marine fossils from TETHYS OCEAN can be observed in Himalayas.
Industry overview
Stable supply with moderate demand growth-
(Apart from cases of stolen or missing containers in Africa)
Primary mine production down by half and increasing restrictions on conflict-produced tantalum is complicating the supply chain
Effect of SEC act, which requires US-listed companies to report sources of materials, causing conflict-free tantalum (contract) prices to increase
Demand, driven by high technology and super alloy industries, expected to increase moderately
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)
This pdf covers theory of continental drift and plate tectonics.
Continental drift
Plate Tectonics
Mantle Convection
Convection currects
Types of Mantle convection
Drivers of the plate motion.
Bibliography_ Lutgens, Tarbuk and Tasa Publisher: Prentice Hall
A great landmass which was thought to be in the geological past, splitting into fragments drifting apart and again colliding into one another is called a supercontinent.1. VAALBARA -First ever made continent was Vaalbara which was 3.6 billion years old, it was named after kaapvaal and Pilbara which were the most ancient cratons present on that land mass. Kaapvaal is in Africa and Pilbara is in western Australia.2. UR- A supercontinent which was 3000 m.y.a and it was smaller than modern day Australia.3. KENORLAND- 2700 m.y.a famous events were HURONIAN GLACIATION. Also known as SNOWBALL EARTH.Responsible for formation of phytoplanktons.and VREDEFORT impact.4. COLUMBIA- Also called as NUNA . Period between Snowball Earth and subsequent Oxidation is called as THE BARREN BILLION.5. RODINIA- 1130 m.y.a.SECOND SNOWBALL EARTH.Also known as NEOPROTEROZOIC GLACIATION.6. PANNOTIA- 750 m.y.aThe formation of Pannotia was associated with the breakup of Rodinia into Proto- Gondwana and Proto-Laurasia. Two oceans were PANTHALSSA and Pan-African Ocean.7. PANGEA- One of the Youngest Supercontinent of all time , there are plenty of evidences of this Supercontinent. Like marine fossils from TETHYS OCEAN can be observed in Himalayas.
Industry overview
Stable supply with moderate demand growth-
(Apart from cases of stolen or missing containers in Africa)
Primary mine production down by half and increasing restrictions on conflict-produced tantalum is complicating the supply chain
Effect of SEC act, which requires US-listed companies to report sources of materials, causing conflict-free tantalum (contract) prices to increase
Demand, driven by high technology and super alloy industries, expected to increase moderately
Lecture 4 Outline Plate Tectonics – Mechanisms and MarginsL.docxSHIVA101531
Lecture 4 Outline:
Plate Tectonics – Mechanisms and Margins
Learning Objectives:
What are the types of plate boundaries?
What processes occur at different types of plate boundaries?
What are hotspots?
How does tectonics build continents and ocean basins?
What Happens at Plate Boundaries?
Plate interiors stable - geologic activity limited to surface processes
But interactions between plates at plate boundaries results in
Magma and volcanism
Faulting and earthquakes
Mountain building
Production of new crust
Recycling of old crust
What are the Types of Plate Boundaries?
Divergent
plates pulled apart
Convergent
plates collide
Transform
plates sheared
Each plate surrounded by different types of boundaries
What are the Types of Plate Boundaries?
What are Divergent Plate Boundaries?
Ridges
Crust pulled apart
Magma by decompression melting in asthenosphere
Cools to make new oceanic crust
Oceanic crust
lithosphere
asthenosphere
magma
central rift valley
faults
North Atlantic Ridge
Mid-Atlantic Ridge
East Pacific Ridge
Indian Ridge
Antarctic Ridge
Where are Divergent Plate Boundaries Found?
Ocean ridge above sea level in Iceland
Where are Divergent Plate Boundaries Found?
What are the Major Geologic Features of the Ocean Ridge?
Shield Volcano
Edge of North American Plate
Fault
Down-dropped fault block
Central rift valley
Filled by lava flows
What are Convergent Plate Boundaries?
Two plates collide with each other – two types
Subduction zone
Between two plates of different density - denser plate subducted
melting in mantle by addition of water from subducted plate
Trench and volcanic arc - chain of volcanoes on overriding plate
Earthquakes
What are Convergent Plate Boundaries?
Collision zone
between plates too buoyant to subduct
Crust thickened and mountains raised instead
Earthquakes but no volcanoes
Indian Plate
Eurasian Plate
Younger and weaker
Older and stronger
deformed
Which Plate gets Subducted?
If both plates composed of oceanic crust
older and denser crust subducted by younger and lighter crust
Overriding plate
Plate boundary
Where Can We Find an Example of an Oceanic Plate Subducted by Another Oceanic Plate?
Pacific Plate subducted by Philippine Plate at Mariana Trench
Pacific Plate
(older)
Philippine Plate
(younger)
Japan Trench
Mariana Trench
Challenger Deep
Eurasian Plate
Which Plate gets Subducted?
If one plate of continental crust and one of oceanic crust
denser oceanic crust subducted by lighter continental crust
Material too light to subduct added to continent as accreted terranes
sediments, volcanic islands, fragments of continental crust
Where Can We Find an Example of a Collision Zone?
Indian and Eurasian Plates
Collision began 45 mya when subduction completely closed ocean basin
Himalaya and Tibetan Plateau
Recent or continuing collisions produce Earth’s tallest mountains
50 mya
today
Closing Ocean
Spreading Ocean
14
Oblique motion betw ...
This tacklesabout locating epicenter,3 typesof plate boundaries hotspot.
A ppt presentation for module 1 in 1st quarter in grade 10sciencein the Philippines.
Feel free tomessage mefor any corrections/suggestions forimprovement.
Plate Tectonics
Chapter 19
Plate TectonicsPlate tectonics - Earth’s surface composed thick plates that moveIntense geologic activity is concentrated at plate boundariesCombination of continental drift and seafloor spreading hypotheses proposed in late 1960s
Review: Three Types of Plate Boundaries
But how do we
know that plates
move at all ?
Transform Convergent Divergent
(strike-slip) (subduction) (spreading)
Early Case for Continental DriftPuzzle-piece fit of coastlines of Africa and South America has long been known
In early 1900s, Alfred Wegner noted South America, Africa, India, Antarctica, and Australia have almost identical rocks and fossils
Early Case for Continental DriftGlossopteris (plant), Lystrosaurus and Cynognathus (animals) fossils found on all five continents Mesosaurus (reptile) fossils found in Brazil and South Africa only
Glaciers Most of the Earth's ice is found in Antarctic continental glacier. Where are some other continental glaciers ?
FIGURE 10.5 Iceberg calving at Wrangell-St. Elias National Park, Alaska. Calving occurs when huge blocks of ice break off at the edge of a glacier that has moved to a shoreline. [Tom Bean.]
Glacial striations on a rock from stones grinding at the base of a heavy ice sheet leave these shiny linear marks on the bedrock below.
FIGURE 10.18 Glacial striations on bedrock in Glacier Bay National Park, Alaska. Striations are evidence of the direction of ice movement and are especially important clues for reconstructing the movement of continental glaciers. [Carr Clifton.]
Glacial Characteristics Glaciers flow downhill as a solid mass that creates channels, and walls made of ground up rock debris known as a merraine.
Erosional LandscapesErosional landforms produced by valley glaciers include: U-shaped valleys Hanging valleysSmaller tributary glacial valleys left stranded above more quickly eroded central valleys
Early Case for Continental DriftWegner reassembled continents into the supercontinent Pangaea
Late Paleozoic glaciation patterns on southern continents best explained by their reconstruction into (Pangaea) Gondwanaland
Early Case for Continental DriftCoal beds of North America and Europe indicate Laurasia super continent
Continental Drift hypothesis initially rejected Wegener could not come up with viable driving force continents should not be able to “plow through” sea floor rocks
The Earth's Magnetic Field
Can Give Us Clues
Paleomagnetism and Continental Drift RevivedStudies of rock magnetism allowed determination of magnetic pole locations (close to geographic poles) Paleomagnetism uses mineral magnetic alignment and dip angle to determine the distance to the magnetic pole when rocks formedSteeper dip angles indicate rocks formed closer .
A collection of Photographs and Maps from the boxing day earthquake and tsunami. These should be used in conjunction with your module notes, the blog and your own research as part of a megaquake and tsunami case study.
Tectonics: Volcanoes - Case Studies and Picturesgeomillie
A collection of images of the wonderful and weird variety of volcanoes across the globe, most of these form part of a mini case study that you should have some sort of anecdotal evidence for use in an essay.
Some pictures highlighting the effects of the 2008 Storm, this was one of the largest low pressure systems to affect the UK since the "Great Storm" of 1987.
An overview of the key stats, and the issues behind the soon to expire protocol. There are more detailed discussions on the blog and for you to read about as part of you own research. You should also form an opinion on the effectiveness of the protocol and subsequent COP's especially the COP15 at Copenhagan and the associated Copenhagan Accord
A collection of images from the "Great Storm" that was not a hurricane of 1987. To be used in conjunction with your module notes and independant research on the storm. Note you also need to know a few stats, and a comparison to the 2007 storm event
An introductory Powerpoint to the final module, this civers the basics of the climate system, how the atmosphere is layered, the effects on all layers caused by increasing altitude, the global pattern of surface wind circulation and an introduction to ocean circulation
Climate: Climatic Change - Evidence, Cycles and The Futuregeomillie
A PowerPoint used in class to cover the key forms of evidence you need to know for the Exam. Key Questions are likely to be focused on how we can gain information of past climatic change, and how it can be used to predict future, and I would expect you to be able to comment on the usefulness of the different types. For instance, Ice cores are highly accurate and quantifiable evidence, but gaining them is expensive, and only gives a climatic record for the site at which the snow formed. However, they do provide the longest record of change.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
2. How do we know this?Part 1 – older evidence Biology – same fossils in different parts of the world Geology – same rocks in different parts of the world Climate – fossils of plants that live in tropical conditions in Antarctica
3.
4. How do we know this?Part 2 – New evidence The Mid Atlantic ridge (1948) Paleomagnetism and the reversal of the earths magnetic field (1950’s) Sea floor spreading – dating of the sea floor rocks (1960’s)
5. Convection – driving forces Very slow convection currents flow in the asthenosphere. These currents provide horizontal forces on the plates of the lithosphere much as convection in a pan of boiling soup (must be Heinz tomato) causes a crouton on the surface of the water to be pushed sideways.
6. Re-cap 6 major pieces of evidence for plate tectonics/continental drift Biological, Geological, fit of the continents, MOR discovery, absolute dating of rocks, mapping of the sea floor Two types of plates – Continental and Oceanic Structure of the Earth
7. Boundary types Divergent – plates moving apart Convergent – three potential combinations: Oceanic vs. Oceanic Continental vs. Oceanic Continental vs. Continental Conservative – movement is lateral only
9. Divergent Boundaries Start intra-plate (current e.g. the Rift Valley) Upwelling of magma in a plume – driven by thermo nuclear reactions at the core mantle boundary Plume rises and convection starts at the base of the lithosphere
10. Rifting As convection commences the plate is thinned out by a series of extension faults. As the plate becomes thinner, volcanoes and lakes start to form in the valley (NB East Africa) More volcanoes continue to form until a complete ridge exists, the plate is forced apart and new oceanic (basaltic) crust begins to form on either side As the lakes connect, and the level of the land drops, the ocean floods the valley and forms an elongate sea such as the Red Sea
11. The Rift Valley and Associated Features Eventually a new plate will form (it will be called the Somalia Plate, and the rest of Africa, the Nubia Plate. The sea will flood the valley and connect to the Red Sea Ensure you label these directions of movement onto your maps
12. The Mid Ocean Ridges The lines of submarine volcanoes that form a continuous feature throughout the worlds oceans These are the centres of spreading, and the youngest oceanic rocks are found closest to the ridge
13. Transform Faults The spreading does not occur at the same rate along the ridge Transform faults offset the ridge giving it a blocky appearance Distance between the faults varies, and they are responsible for many undersea earthquakes, but the lack of vertical displacement rarely generates Tsunamis
14. Islands on the Ridges Particularly large volcanoes can become islands – they do sink as they move away from the ridge to become Seamounts and Guyots Iceland is the largest MOR island – it is believed there is a plume beneath the island causing intense volcanism
15. Hazards Frequent low grade seismicity (earthquakes below 5 on the Richter Scale) Intense and frequent volcanism Ultra slow spreading is 10mm/yr (Atlantic), ultrafast 100mm/yr (East Pacific and Galapagos)
17. Opening and closing of Oceans Rifting is the control over opening and closing The world is a fixed size, as such if new crust is created, crust somewhere else must also be destroyed Hence there are subduction zones at the edges of most continents Where will the next one open up?
18.
19. Convergent Boundaries There are three types and you need to know the features and hazards you would expect to find on each
20. Ocean vs Ocean Stage 1 – Subduction produces partial melting and the formation of a chain of volcanoes. An Island Arc Stage 2 – Build up of intrusive and extrusive igneous material, mixed with sediments forms larger Islands Stage 3 – The Island Chains join up and sediments form an Accretionary wedge or prism which builds on to the fore arc area.
21. Hazards Volcanoes – wide variety of types, explosive and effusive Earthquakes – can be very powerful Tidal waves – offshore earthquakes generate waves and the steep islands often suffer inundation, the other cause is collapse of oceanic islands generates regular waves (Stromboli)
22. Structure of Subduction Zones Island Arcs (Archipelago) are often curved – i.e. the Aleutian Islands, the Philippines, Malaysia, Indonesia and the Aeolian Islands (small scale)
23. Oceanic vs. Continental Stage 1 – Weight of continental sediments causes subsidence of the crust Stage 2 - Subduction develops and an Island Arc forms Stages 3&4 Compression from Plate movement causes the crust to thicken and shorten through Folding and Thrust Faulting. Fold Mountain Chain is formed. Ie The Andes
24. 3D view Mt St Helens is formed in this way, the Cascades represent the curved line of volcanoes just inland on the Western Seaboard of the US. Hazards: Very explosive Volcanoes (MSH, Popocatepetl – no really)
25. Characteristics of Subduction Zones Trenches – generally 5-8 km deep, up to 11km – deepest is the Mariana Trench Belt of earthquakes, shallowest closest to the trench Island arcs (archipelago)
26. Continental Collision Note: This process of Mountain Building is often referred to as an Orogeny, and the mountains as “Orogenic Belts” The best case study of this type of collision is in the Himalaya, where the process is still active today
28. Brief History India has moved northwards over the last 100 ma. It started well below the equator and an ocean existed to its north called the Tethys The Subduction of the oceanic lithosphere thickened the plate to 100km and forced up the fold mountains
29. Hazards The plate has moved very rapidly – 200mm/yr Earthquakes are a major hazard The crust is too thick for diapirs of magma to make it to the surface so there are no volcanoes A significant hazard is the potential for mass movement. Given India's tropical/desert location, the young mountains being steep and the likelihood of earthquakes the risk is high, added to that is the development of low quality housing on slopes and monsoonal weather and events such as Chittagong become high risk
30. Conservative Boundaries No subduction or abduction Plates try to move laterally past each other Most famous – the San Andreas Fault No volcanism Generates massive earthquakes
31. Hotspots These are not boundaries as such, but a surface representation of mantle plumes Plates do not always split above mantle plumes, but as the plate moves over the magma source, it generates a chain of Islands The orientation of the island chains gives the direction of plate movement relative to the plume
32. Hawaii Chain of islands, connected to the Emperor Seamount chain (submerged) The Islands become older to the North West indicating the plate is moving NW. This was anticipated before the discovery of continental drift as the islands become shallower in gradient, more advanced in vegetation succession and have deeper soils to the NW
33. Other Hotspots Yellowstone Caldera is probably the biggest and highest risk (see “Supervolcano” the thrilling docu-drama), Iceland is unusual being a large plume underneath a divergent boundary. Note the overlap with popular tourist destinations! Note: the mantle plume theory is still hotly debated and poorly understood – it is one of the few remaining mysteries of tectonic theory, which is otherwise now widely accepted
34. Today’s activity A3 sheet – you should have taken notes on the different types of boundaries, make sure you have enough detail to revise from The sheet has boxes for all the major surface expressions of plate tectonics – describe each one and the use the atlases and textbooks in the room to locate our major case studies for the rest of the year. Enter a very short description into each box Plate movements – familiarise yourself with the plate movements and label them onto your map with the names of the plates, the large poster map will give you most of the information