How do plate tectonics play a role in mass extinctions?
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The formation of supercontinents (like Pangaea) can reduce niche habitats and reduce species diversity through mass extinction.  There is also some evidence for magmatism associated with continental rifting emitting enough gases to effect the climate.  If you want to know more about huge volcanic flows that could do this, google "Deccan Traps" or "Siberian Traps" (which seem to have occured at roughly the same time as the end-Cretaceous extinction and the end-Permian extinction, respectively).
399368
I just had to do a poster for my historic geology class.\n50 mya= Earliest whales, molluscs cover from mass extinction\n40 mya= Tropical forests at high latitudes, Arboreal browing animals dominant, earliest bats, peak of warming.\n35 mya= Excticion of rummulitids and other warm-water marien life, resuption of arc volcanism, Climatic deterioration, early Antarctic glaciation.\n30 mya= Forests break up due to cooling and drying\n25 mya= Giant Hornless Rhinoceros predominant, San Andreas Fault created, beginning of Tejas Sequence of ocean fluctuations.\n20 mya= Grassy savannahs monnon in mid latitudes, Antarctic glaciers return.\n15 mya= Mastodonts escape Africa, Diversification of fast-running grazing mammals, Cascaade Arc Basin and Range extension created.\n10 mya= Steppes Replace Savannas, Arctic icecap created.\n5 mya= Extinction of many savannah mammals.\n4 mya= Extinction of large mammals at end of plesitocene.  Mediterranean dries up.
244145
Not exactly pressure.  Tectonic plates under the Earth's crust are constantly in motion.  When they collide, mountains are formed.  These mountains become volcanoes when the tectonic plates hit each other and then move further apart, therefore creating a direct channel to the molten core of the earth.  When the molten material builds up it shoots up the hole of a volcano.
590403
heh... are you referring to ecological endangered hotspots or hot spots under plates that cause volcanic activity?\n\nThere are... way to many ecological hot spots particularly in tropical areas in South America, Africa and South Asia.\n\nAs for hot spots associated with plate tectonics, there are many I'm sure but the Hawaiian Island chain is probably the biggest and longest.  Yellowstone wouldn't be a hot spot really, it's pretty close to a plate boundary and it's activity I would think is left over from this.  Hot spots are unusual for continental plates.  It seems like many island chains could have been formed by similar hot spots under ocean plates though.
1089394
earthquakes occur when the tectonic plates that cover the earth noticably shift. These movements can also form volcanoes and trenches
616929
1) when the plates collide - eg himalayas\n2) when the plates pull apart - eg mid oceanic ridge, it is underwater but still a mountain chain\n3) when one subsides under another, when that plate melts, it can cause a chain of volcanoes, which can also make mountains - pacific rim
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Perhaps... the weather during the early part of the Cretaceous was warmer than today (and more uniform.)  I'm actually in the process of writing a paper exploring the possibility of hadrosaur hibernation in northern Alaska.\n\nI took a tour of a dinosaur resource center today.  The tour guide said that ability to adapt is what saved KT survivors.  Crocodiles can go months without eating.  Birds migrate.  Fish could swim to deeper water.\n\nIt is still highly debated to what caused the Cretaceous Tertiary extinction.
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Holy cow-thats a Master's thesis project at least!  Ok, there are lots of theories out there concerning a cataclymic hit-and since both she and the people she is comparing also believe in the asteroid theory, we have to just think of all the things that could happen, reasonably:\nThe ashes from the volcanoes could block out the sun so drastically that it became too cold for the dinosaurs to live\nThe ashes blocked the sun out sufficiently to kill the major plant life, so the herbivorous dinos starved, and then the carnivores starved.\nThe volcanoes spewed out sufficient CO2 that the dinos suffocated\nThe volcanoes spewed out toxic gas that poisoned the dinos.\nThe volcanoes subtly changed the climate so that over thousands or hundreds of thousands of year, other lifeforms, such as mammals, birds, and the surviving reptiles, gains a major advantage and caused the dino extinction.\nAbout the meteor:  Either you could hypothesize that the volcanoes erupted spontaneously, and it had nothing to do with meteors, or that the meteors by themselves weren't a killing force but disrupted the crust of the Earth sufficient to open up volcanoes all over the Earth, or that the meteor alone killed most of the dinosaurs, and the resulting volcanoes killed off the rest.\nI didnt mention the effects of tsunamis and earthquakes caused by the volcanoes because that wouldnt reasonably be enough to kill off all the dinos.\nHope those ideas help-good luck.
14315
Tectonics (and therefore earthquakes and volcanoes) is driven by the internal heat of the planet.\n\nEver since the Earth formed it has been cooling, so if anything tectonic activity is on a constant decline. The loss of heat is very slow though, so from the point of view of recorded human history there has been very little change.
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no... because i know, before my class even started the topic of year 9 geology (i think the topic is called "Reading the Earth") - and i'm in year 9, i think this is form two for other countries and can be also known as grade 9), i know that the mountain ranges in the asian area was cause by plate tectonics crashing into each other - and through the topic i'm studying right now, I learnt that the type of boundary that is between the plates is called the collosion boundary where two plates of similar thickness collide creating mountain ranges as the ground is pushed upwards and downwards.
95629
You should look into the definition of scientifc theory and laws. Plate tectonics will never become a Law because that terminology does not apply to Plate Tectonics. The fact that it is known as a theory does not mean it is still hypothetical or based on conjecture. This is the common meaning of the word theory (that so confuses the creationists) but is not the scientific meaning of the word. Plate tectonics is well established and well tested. There are some causative parts that are still not completely understood because we have not been able to obsverve the interaction between the mantle and asthenosphere, but that fits well into the definition of a scientific theory. In many fields of science a THEORY is the highest level of certainty and the term LAW does not apply. \n\nI quote:\nIn science, a body of descriptions of knowledge is usually only called a theory once it has a firm empirical basis, i.e., it\n\n   1. is consistent with pre-existing theory to the extent that the pre-existing theory was experimentally verified, though it will often show pre-existing theory to be wrong in an exact sense,\n   2. is supported by many strands of evidence rather than a single foundation, ensuring that it probably is a good approximation if not totally correct,\n   3. makes predictions that might someday be used to disprove the theory,\n   4. is tentative, correctable and dynamic, in allowing for changes to be made as new data is discovered, rather than asserting certainty, and\n   5. is the most parsimonious explanation, sparing in proposed entities or explanations, commonly referred to as passing Ockham's razor.\n\nThis is true of such established theories as special and general relativity, quantum mechanics, plate tectonics, evolution, etc. Theories considered scientific meet at least most, but ideally all, of the above criteria. The fewer which are matched, the less scientific it is; those that meet only several or none at all, cannot be said to be scientific in any meaningful sense of the word.\n\nPhysical laws are distinguished from scientific theories by their simplicity. Scientific theories are generally more complex than laws; they have many component parts, and are more likely to be changed as the body of available experimental data and analysis develops. This is because a physical law is a summary observation of strictly empirical matters, whereas a theory is a model that accounts for the observation, explains it, relates it to other observations, and makes testable predictions based upon it. Simply stated, while a law notes that something happens, a theory attempts to deal with why or how it happens."
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Really, the answer to your question is simply: Plate Tectonics. Read below for details.\n\nEarthquakes: \nIt all comes down to stress and strain from the interaction of different plates, chiefly at the boundaries. It is not 'the plates rubbing together' as many people say; or at least that's a very simplistic view.\n\nPlate tectonics causes stress on the continents and oceans, all over the surface of the earth. In some places, the stress is very small (usually within the plates). Elsewhere, the stress is high, usually where the plates meet each other. Since each plate moves, when two come in contact, the stress each other. They can push on each other and cause compressional stress, they can pull with extensional stress, and they can slide past or shear each other with tensional stress.\n\nFaulting, causing earthquakes, comes from the fact that this stress is building up all the time, but rocks and continents are strong materials. Just like hitting a rock with a small hammer, you do put stress on it, but a small amount. It would take a sledgehammer to put enough strain (effects and accumulation of stress) to build up and cause breakage. In the earth, the area around an active fault builds up strain from the stress of plate tectonics. Most faults become locked, because of this strength, and thus can not release their strain. Away from the fault, the stress produces very small and slow movement of the rock masses as a whole. Eventually, the strain is too much and the rest of the plate has moved too far and the fault releases the strain build-up all at once in a big stress release called an earthquake. This is called the elastic rebound theory, and it explains most (but not all) movements.\n\nThis is why an earthquake's size is relative to the fault size. The bigger the fault, the bigger the strain build up, and the bigger the release in an earthquake. Subduction zones and collision zones, where large portions of plates actually can rub together as a whole, have the really big earthquakes, like the 2004 Sumatra earthquake. In other plate boundaries, the entire plate boundary does not act together, so the faults become spread out and many faults take up the strain from the tectonic stress, like with the San Andreas Fault in California (it only takes up ~3/4 of the stress between the plates).\n\nEarthquakes are really tricky things; there is still so much we need to learn. As of now, there is no way to predict them, but we can say where the danger is highest and about how long between events.\n\nVolcanoes:\nThere are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.\n\nVolcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!\n\nThe other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.\n\nMountain Belts:\n\nNon-volcanic mountain belts are caused by compressive stress in plate tectonics. This can be 1. fold and thrust belts in highly compressive subduction zones (almost always from oceanic beneath continental subduction, e.g. east Andes, Rockies) or 2. continental-continental collisions (e.g. Himalaya, Appalachian).
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A destructive plate boundry causes one plate to be subducked below another, (sucked under basically) this causes it to melt and then rise to the surface where it forms the Mount Pelee volcano\n\nHope that helps
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(m)\n\nAustralian and American researchers investigating forces exerted on the Indo-Australian tectonic plate have discovered that the considerable stresses being exerted on the plate could be leading to its breaking up.\n\nARC Professorial Fellow, Mike Sandiford, from the University of Melbourne’s School of Earth Sciences was recently awarded ARC funding for research aimed at understanding the forces that drive the motion of the Earth’s tectonic plates and the distribution of stresses in the Earth’s crust that give rise to great earthquakes such as the magnitude 9 Boxing Day Sumatran quake.\n\nProfessor Sandiford says the research shows that as much as 10 per cent of the huge amounts of energy being created at plate connection points at Sumatra and Java are being transferred back into our plate and causing major stresses.\n\n“This is enough stress to contribute to mild earthquake activity in the central regions of the plate, such as in the Australian continent or central Indian Ocean, and provides us with clues as to why our plate has been slowly breaking up,” he says.\n\n“The Indian Ocean quakes are, in effect, leading to the active rupture of the Indo-Australian plate into separate Indian and Australian plates. This new research provides us with important information about the stresses that are driving this drawn out tectonic plate divorce.”\n\nThe research, which was conducted in collaboration with Wouter Pieter Schellart of the Australian National University and David Coblentz of the Los Alamos National Laboratory in the US, will be published in the journal Geology (27 January).\n\nThe research is also important for understanding why smaller intra-plate earthquakes such as the 1989 Newcastle quake, which occurred nowhere near the edge of the plate, take place. Up to now, why earthquakes occur in apparently safe zones in the centre of plates has not been very well understood.\n\nProfessor Sandiford says, “Earthquakes such as the 1989 Newcastle quake that killed 13 people and caused more than $1 billion in damages are just one manifestation of mild tectonic activity that has been affecting the Australian continent for the last 5-10 million years.”\n\nThe new research shows that stresses originating at points of collision between two plates are being dissipated back into our plate and generating enormous internal stresses.\n\nThe ARC funded project will map the spatial and temporal pattern of this tectonic activity and relate it to the factors that drive the motion of the Indo-Australian plate.\n\n“This research will contribute to our understanding of the factors that drive plate motion, to earthquake risk assessment in Australia and other comparatively stable continental regions, and to the factors that have shaped our distinctive Australian landscapes,” he says.\n\nBACKGROUND INFORMATION\n\nWhat causes tectonic plates to move?\nThe Earth is made up of a series of layers. The outermost layer is called the crust and the innermost is the core. In between lies an area called the mantle (in turn made up of upper and lower mantle), which is arguably the most important when it comes to understanding where big earthquakes occur.\n\nThe outer part of the Earth, comprising the crust and top 100 or so kilometres of the mantle (together called the lithosphere), consists of a collection of eight major plates which almost fit perfectly together. The continents and oceans all lie on these plates, the major ones referred to as the African, Eurasian, Indo-Australian, Antarctic, Philippine, Pacific, Nazca, North American and South American, depending on their geographic location.\n\nThese plates (also referred to as tectonic plates) float on the softer mantle underneath. Convection currents within the upper mantle layer are a major driving force driving plate motion and therefore behind earthquake activity.\n\nThe lower sections of the mantle closest to the molten core of the earth are also the hottest parts of this la
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tectonic plates or continental drift
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The plates consist of an outer layer of the Earth, the lithosphere, which is cool enough to behave as a more or less rigid shell. Occasionally the hot asthenosphere of the Earth finds a weak place in the lithosphere to rise buoyantly as a plume, or hotspot. \n\nOnly lithosphere has the strength and the brittle behavior to fracture in an earthquake. \n\nThe map below locates earthquakes around the globe. They are not evenly distributed; the boundaries between the plates grind against each other, producing most earthquakes. So the lines of earthquakes help define the plates: \n\n\nIn cross section, the Earth releases its internal heat by convecting, or boiling much like a pot of pudding on the stove. Hot asthenospheric mantle rises to the surface and spreads laterally, transporting oceans and continents as on a slow conveyor belt. The speed of this motion is a few centimeters per year, about as fast as your fingernails grow. The new lithosphere, created at the ocean spreading centers, cools as it ages and eventually becomes dense enough to sink back into the mantle. The subducted crust releases water to form volcanic island chains above, and after a few hundred million years will be heated and recycled back to the spreading centers.
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plate tectonics provides an explanation for the continental drift hypothesis.