NESTA-US□ sur Twitter : "The breaking up of Gondwana—Precambrian terranes(pink); mid-ocean ridge growth(red); mantle plumes (yellow stars), creation of large igneous provinces (blue/orange) & transforms/fracture zones(pale blue) #E. Ancient Earth globe. *****Geological time: 4.5 billion years of Earth history Life starts ~ 4,000 Myrs Oxygen rises 2,300 Myrs Multicellular life 1,500 Myrs 1st animal 580 Myrs 1st vertebrate 380 Myrs 1st mammals 225 Myrs 1st primate 55 Myrs 1st humans ~ 200,000 yrs ago. *****Lithospheric plates are part of a planetary scale thermal convection system. The energy source for plate tectonics is Earth’s internal heat while the forces moving the plates are the “ridge push” and “slab pull” gravity forces.
*****What drives #platetectonics? It was once thought that mantle convection could drive plate motions but current models have plates moving as part of a gravity-driven convection system. *****Measuring Plate Tectonics with GPS / GIS. *****Paleogeography & Plate Tectonics (incl City Migration Trajectories) Mapping Ancient Oceans - GeoLog incl tectonic plates animation. An example of a new map identifying potential chunks of ancient oceans now located deep inside Earth.
A vote map at 1400 km depth has been projected to the surface, and is overlain with the position of the continents (grey-white) at around 120 Million years ago. Credit: G Shephard (CEED/UiO) using GPlates software. This guest post is by Dr Grace Shephard, a postdoctoral researcher in tectonics and geodynamics at the Centre of Earth Evolution and Dynamics (CEED) at the University of Oslo, Norway.
This blog entry describes the latest findings of a study that maps deep remnants of past oceans. Her open access study, in collaboration with colleagues at CEED and the University of Oxford, was published this week in the Nature Journal: Scientific Reports. Quick summary: Visualization of the internal geological forces of the Earth… October 28, 1965, geophysicist Edward Bullard, using the first "tectonic. What the world looks like without water.…
This 1987 map of the breakup & dispersion of Pangea gives me a bit of vertigo. Scientists propose that vast amounts of sediment eroded from Earth’s continents were necessary to lubricate the wheel of #PlateTectonics. What planet Earth might look like when the next supercontinent forms – four scenarios. The outer layer of the Earth, the solid crust we walk on, is made up of broken pieces, much like the shell of a broken egg.
These pieces, the tectontic plates, move around the planet at speeds of a few centimetres per year. Every so often they come together and combine into a supercontinent, which remains for a few hundred million years before breaking up. The plates then disperse or scatter and move away from each other, until they eventually – after another 400-600 million years – come back together again.
The last supercontinent, Pangea, formed around 310 million years ago, and started breaking up around 180 million years ago. Twitter. And what would happen if a slab meets a plume in the middle of the mantle? Side view and top view below. #Monash #Geodynamics #slabs #plumes. @m_chiles "Convection currents drive the plates'! (Rather than being mere passengers, plates form an integral part of the convection system and slabs can drive and change mantle convection patterns).
@m_chiles "Continental plate' - can you name one? @m_chiles How many mistake can you see in this diagram (A level geography textbook)? Plates are made of 'crust and lithosphere'. (Even geography examiners in their revision books - agh!)… Mantle plumes and mantle dynamics in the Wilson cycle. By Philip J. Heron. Read more in the Lyell … #geology #mantle #tectonics #Wilsoncycle. AGU's Eos sur Twitter : "The Earth blobs (seen below) may fuel hot spot volcanism, supervolcanoes, and plate tectonics. But scientists have no idea what they are... Or where they came from. Dig into the mystery on Eos #AGU100 #Ear. Mantle plumes and mantle dynamics in the Wilson cycle. By Philip J. Heron. Read more in the Lyell … #geology #mantle #tectonics #Wilsoncycle… Fate of the subducted oceanic crust revealed by laboratory experiments. A wrench in Earth's engine: Stagnant slabs. The earth in 250million years..? Index. Twitter.
Cosmic pile-up gives glimpse of how planets are made. Image copyright NASA Astronomers say they have the first evidence of a head-on collision between two planets in a distant star system.
They believe two objects smacked into each other to produce an iron-rich world, with nearly 10 times the mass of Earth. A similar collision much closer to home may have led to the formation of the Moon 4.5 billion years ago. The discovery was made by astronomers in the Canary Islands observing a star system 1,600 light years away. @HafsaBobat @GeogMum I dislike the terms Constructive/Destructive. Is the subducting plate actually destroyed? Seismic tomography (ala @philipheron) suggests that model is too simple. Over the last 10 years exam boards have introduced the more accepted te. @peteloader1 @teacheratseaMAR @HafsaBobat @JCCEarthSci No problem Pete! Later in the talk (~33 mins) I clarify that subduction can modify mantle convection currents and is in a dynamic system with the mantle (cold stuff going down helps promote warm mater. @HafsaBobat @JCCEarthSci The Mantle is NOT semi-molten. The @geolsoc Key Stage 3 Plate Tectonics website does not make this mistake so why must we continue to teach scientific concepts incorrectly when it is so easy to teach it otherwise. It is poor scien.
A note of caution. The mantle DOES convect though it appears convection is driven by plate motion, rather than the reverse role. So this spec wording could be interpreted as implying the role 'limited'.… Teacheratsea sur Twitter : "@geology_bham @DurUniEarthSci @CU_EARTH - Have you any views on above? My understanding is that hot mantle convection as the main driver of plate movement has been disregarded since 1970s. Why is it still fact in the text books.
Peteloader sur Twitter : "The Mantle is NOT semi-molten. The @geolsoc Key Stage 3 Plate Tectonics website does not make this mistake so why must we continue to teach scientific concepts incorrectly when it is so easy to teach it. Simon Kuestenmacher sur Twitter : "Here is a #map of our continents in a short 250 million years. We (assuming we are still around then) will be living nice and close together. Also we will have many wonderful new mountains to climb. #NewZealand will stil. *****Interactive: Ancient Earth globe. *****Interactive animation: The Smithsonian has a very cool interactive globe online that shows volcanic eruptions, earthquakes and emissions over time. Areas of high geologic risk show up really well here. Source. *****How Firing Lead At Dust Clumps is Informing Our Theory of Planetary Formation. (Left) Picture of the laboratory drop tower.
(Right) The expansion of granular clusters from impact. (Credit: Hiroaki Katsuragi and Jürgen Blum) By firing plastic, lead and glass projectiles into clumps of dust, researchers are improving our understanding of how planets form in the universe. Planets start out as loose clumps of dust grains. And, like flour clumps up as you mix it into cake batter, cosmic dust clumps eventually build up to become planets like Earth as gravity pulls them together. Studying Dust Clumps As planets form, they often collide with other matter and objects around them. To recreate these cosmic dust collisions, a team of researchers had to first create realistic dust balls to mimic the cosmic dust that forms planets.
High-Speed Collisions The team then built a drop tower featuring a large glass tube in which vacuum and microgravity conditions mimicked outer space. It’s a way to see the cosmos in your kitchen. *****Tectonics, plate margins by Prof Iain Stewart (video clip) The Ice Age sur Twitter : "#OTD in 1912 German geophysicist and meteorologist Alfred Wegener first presented his ground-breaking theory of continental drift arguing that all the continents had once been joined together as a single landmass. The debate rag. There's Mounting Evidence The Continent of Africa Is Splitting in Two #geographyteacher. *****New research from @Caltech may unravel the mystery of how dust first clumped together to form the 'seed' of new planets. Watch. This is what the Earth might look like when the next supercontinent forms #earth #future…
Structure of the Earth with hotspots. Simon Kuestenmacher sur Twitter : "What would be left of the world's oceans if we pulled a 10m plug in the Marianas Trench emptying the water? @xkcdComic post that inspired the animation Source. #DidYouKnow that gravity isn’t the same everywhere on Earth? And that the @Space_Station isn't in “zero-g”, but rather has about 90% of Earth’s gravity at that altitude. Thierry Gregorius sur Twitter : "As geoscientists we totally take this for granted, but people always love watching our #ArcGIS-based palaeo animations going back 300 million years... here e.g. our @Getech DEM drainage model #aapg #ice2018 #aow2018… https.
*****Ocean elevation animation (bathymetry): If there was a cork at the bottom of the ocean and we pulled the plug to make the water drain, what would the world look like? Fun little mental experiment by @coraman.… I didn't know the architect of continental drift theory was a meteorologist, but I suppose it is all about convection… October 28, 1965, geophysicist Edward Bullard publishes a papers showing how the continental shelves fit together, suggesting that moden continents formed by break-up of a former supercontinet.
Fossil evidence for continental drift theory proposed over 100 yrs ago. #FossilFriday… The beauty of geological time. From the Big Bang to the Holocene (aka, now). Source. Simon Kuestenmacher sur Twitter : "One of my all time favorites! This #infographic helps you to visualize geologic time. Earth came into being at the shoulder, single cell organisms started at the forearm, humans only rocked up at the tip of the finger na. How in 250 million years, Earth will have one single supercontinent, Amasia. Cornwall and south Devon 'originally part of mainland Europe' With what can only be described as unfortunate timing, researchers have discovered that there is a corner of Britain that will forever belong to mainland Europe.
Slab pull v convection: I recommend this explanation from @geolsoc… Chart shows all life on Earth by weight. Makes humans look a quite insignificant. Source. Universität München sur Twitter : "Looking deep into Earth‘s interior: The American Museum of Natural History in New York draws on a 3-D simulation by LMU geophysicists to visualize convective motions in Earth’s mantle. Michael Anenburg sur Twitter : "Science communicators and illustrators. Please stop drawing the mantle as red/orange/yellow (eg this diagram from Wikipedia). It perpetuates the misconception that the mantle is magma or molten or liquid or whatever. It is. #TheDeep of #OurBluePlanet (approx scaled) □surface v v v v v v v v v v v v □deepest whale 2992m v v v □average ocean depth 3682m v v v v v…
Twitter. Simon Kuestenmacher sur Twitter : "Here is a #map of our continents in a short 250 million years. We (assuming we are still around then) will be living nice and close together. Also we will have many wonderful new mountains to climb. #NewZealand will stil. This is how plate tectonics will change Earth in 250 million years… Prediction of continental arrangements 50 million years from now based on present-day tectonic plate motions. Twitter. *****Animation of tectonic plate movements: Ancient Earth globe. *****How deep is the Crust? Here's how deep humans have dug underground. Problem loading page. Theconversation. Earth’s crust is made up of fractured slabs of rock, like a broken shell on an egg.
These plates move around at speeds of about 5cm per year – and eventually this movement brings all the continents together and form what is known as a supercontinent. The last supercontinent on Earth was Pangaea, which existed between 300-180m years ago. "We long for place; but place itself longs..." Anne Michaels, Fugitive Pieces (1996)… This is how plate tectonics will change Earth in 250 million years… Problem loading page. If you haven’t already,download @RGS_IBGschools podcast.I listened to this one on way in this morning, was excellent. Continental interiors may not be as tectonically stable as geologists think. A University of Illinois-led team has identified unexpected geophysical signals underneath tectonically stable interiors of South America and Africa.
The data suggest that geologic activity within stable portions of Earth's uppermost layer may have occurred more recently than previously believed. The findings, published in Nature Geoscience, challenge some of today's leading theories regarding plate tectonics. Research has found that the movements of a supercontinent even older than Pangaea, which existed between 335 and 175 million years ago, caused part of North America to get stuck to Australia. What Really Happens When Earth’s Magnetic Field Flips? Many times over our planet’s history, Earth’s magnetic poles have reversed, meaning that sometimes a compass pointing north will be aimed at Antarctica rather than the Arctic.
This might sound strange, but it’s a relatively predictable quirk. Powered by the machinations of the planet’s spinning iron core, this process of geomagnetic reversal has been doing its thing without much fanfare for eons. That is, until this week, when a book excerpt describing the phenomenon appeared online. Shortly afterward, numerous websites began trumpeting the doomsday around the corner, a geomagnetic apocalypse in which tumors run rampant, satellites fall from the sky, and life on Earth will cease to exist as we know it. True, life on Earth almost certainly will be different than it is today in multiple thousands of years. First thing’s first: Are we all going to die? Fact of the day: active subduction of tectonic plates occurs below an area of the Earth's surface that is roughly equivalent to the total surface area of the North American continent. Just calculated this for a research proposal.… Communities living on the Pacific Ring of Fire have been responding to serious volcano + earthquake activity this week. (Data: @UNISDR)…
A bit of the world that we don't normally get to see well from most maps.… Biolojical sur Twitter : "Mass in grams 10^33□ . . . . 10^28□ . 10^26□ . . . . . . . . 10^17□ . . 10^14□ . . 10^11□ . 10^9□ 10^8□ 10^7□ 10^6□ 10^5⛹️ 10^4□ 1000□ 100□ 10□ 1□ 0.1□ 0.01□ 0.001□ . . . . . 10^-9□human cell . . 10^-12□bacterium . . 10^-15□viru. Fantastic picture shared by @galka_max of Pangaea with current international borders #geographyteacher □… *****Tectonics can be used to predict the future position of Earth's continents. 50 million years in the future the Mediterra… The Earth permanently hums at frequencies between 2.9 and 4.5 millihertz, but we don’t notice because that’s about 10,000 times lower than h… #OTD in 1912 German geophysicist and meteorologist Alfred Wegener first presented his ground-breaking theory of continental drift arguing th…
Marie Tharp: Uncovering the Secrets of the Ocean Floor - with Helen Czerski. BBC World Service - Discovery, The Day the Earth Moved. Geothermal gradient. #Geology #GeologyPage Earth’s history should include ‘pre-plate tectonic’ and ‘plate tectonic’… What happens when you pull the plug on the Marianas Trench. Reddit user: Vinnytsia The Mariana Trench or Marianas Trench is the deepest part of the world's oceans.
It is located in the western Pacific Ocean, an average of 200 kilometers (124 mi) to the east of the Mariana Islands, in the Western Pacific East of Philippines. It is a crescent-shaped scar in the Earth's crust, and measures about 2,550 km (1,580 mi) long and 69 km (43 mi) wide on average. It reaches a maximum-known depth of 10,994 meters (36,070 ft) at a small slot-shaped valley in its floor known as the Challenger Deep, at its southern end, although some unrepeated measurements place the deepest portion at 11,034 meters (36,201 ft).
For comparison: if Mount Everest were dropped into the trench at this point, its peak would still be over 1.6 kilometers (1 mi) underwater. Key Stage 2: Mountains, volcanoes and earthquakes. #Geology #GeologyPage “Knowing what a chicken looks like and what all the chickens before it looked lik… Here's how deep humans have dug underground in the past 100 years. New study sheds light on how earliest forms of life evolved on Earth. A new study led by ANU has shed light on how the earliest forms of life evolved on Earth about four billion years ago.
In a major advance on previous work, the study found a compound commonly used in hair bleach, hydrogen peroxide, made the eventual emergence of life possible. Lead researcher Associate Professor Rowena Ball from ANU said hydrogen peroxide was the vital ingredient in rock pores around underwater heat vents that set in train a sequence of chemical reactions that led to the first forms of life. "The origin of life is one of the hardest problems in all of science, but it is also one of the most important," said Dr Ball from the Mathematical Sciences Institute and Research School of Chemistry at ANU. The research team made a model using hydrogen peroxide and porous rock that simulated the dynamic, messy environment that hosted the origin of life. Dr Ball said the high temperature fluctuations must not rise too high or occur too often. More information: Rowena Ball et al. 59 Oranges and Earth. We see many meteors from the @Space_Station but I was never able to get one on camera... this time I got lucky and filmed a #fireball, a ve…
Earth Learning Idea - Innovative, Earth-related teaching ideas. The Geological Society. *****Journey to the Centre of the Earth. I ❤️ the #elevator here at the @otago #geology department □□□ We should get one @BergenBasins @uibgeo □