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As with all things worldbuilding and writing, it's just up to you to decide how much you want to bend reality or play with the rules. My personal route, in an otherwise earthly scenario, would be to say that the rock simply comes out of a volcano and travels until it solidifies, which could actually be a fair distance. Some applications of this would be ...


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Really Big Lopsided Eruption Some time ago, the mountain got a lot bigger, and either had one side fall over at the beginning or evolved a channel to the side as it crumbled. Crucially, there must be significant height to drop lava at the end of its channel, or it will pile up and you won't have a channel anymore. The new lava pumped up from inside must ...


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River No, Lake Yes you just can't have a steady state lava river, the shape of a river means the lava is cooling which means the river is getting smaller so even if you feed in more lava it follows a different path. Lava Lakes however are a real thing and steady state lava lakes can exist for centuries because the lava can circulate and get reheated as it ...


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River of molten metal. This "river" does not actually flow - rather it is static. Within its impervious rocky banks, the molten iron comprising the river extends down to the mantle, and the conductivity of the metal means that the vast internal heat of the planet can keep the metal molten. Perhaps the metal is at this surface position because of an ...


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It's not completely impossible, but it requires some unusual conditions. First: The 'source' of your lava river is always going to be an active volcano, by definition, but volcanos don't always involve tall mountains. There are also Shield Volcanos which form relatively low, broad rises in the terrain where the lava pushes to the surface. It's important ...


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Not really. There have been tons of long lived lava flows in history, but they dramatically alter the land. Lava cools as it flows, creating layers of solid rock that build up. This happens on volcanic islands where the lava can flow into the ocean, expanding the size of the island. Lava flows exposed to air will cool and form a crust over them while the ...


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On Earth, continental drift is caused by volcanic activity; so, are oceans. So without a lot more knowledge of what other worlds are actually like to maybe contridict that, a little bit of simple reasoning tells us that a planet with oceans should have significant continental drift over that time scale which makes 3-4 billion years of continental separation ...


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Formation of super continents and their subsequent breakup is cyclical in nature. Supercontinent Cycle On geological time scales it would be reasonable to assume that there was a period in which there were only 2 major landmasses present on the planet. Your timescale of 3-4 billion years is off by an order of magnitude of the Earth's, but it would be ...


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First thing first, Pangea means "all the earth", because it encompassed the whole of the emerged land back in those times. So, from a logic point of view there can be no two Pangea. From a geological point of view, if you look at the appearance of the present emerged lands, you might argue that we have less than 5 continents: Asia, Europe and Africa are a ...


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We're pretty sure it's happened right here on a earth, a few times. Pangea didn't break up straight into seven continents, it was two big bits for a while both before it formed and after it broke up, and Pangea wasn't the first time all the continents had joined together either. So, not only is there no process that prevents it from happening, it's pretty ...


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A possible side effect: displacing such huge amount of material could perceptibly shift the planet's rotation axis. It is believed to have actually happened on our Moon due to volcanism moving the material. So it should not be done haphazardly. If this causes the artificial crater to end up closer to pole after the excavation, it will have colder climate ...


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What I should have been looking at is the Geoid of Mars & the depth from it to the mantle The thickness of the crust varies between 50 km & 22 km due to the Geography & features (rock layers) above the Geoid while the distance from it to the mantle should be reasonably uniform. I presume the putative Geoid of Mars is the altitude used for ...


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Since nothing exactly like this exists on Mars, let's look at the best real-life example of what you're describing: A crater. On Mars Hellas Planitia is one of the oldest and largest craters on Mars. It was formed during the Late Heavy Bombardment, which started around 4.1 BYA. At more than 7 km deep, it's one of the deepest craters in the solar system. ...


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Valles Marineris reaches a depth of 11 km, while Olympus mons reaches 25 km of height, together they make the gap you envision. Olympus mons is thought to be 200 million years old, while Valles Marineris should count 3 billion years. Therefore the lower limit for existence of such a height difference seems to be at least 200 million years.


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As I interpret it, your deity comes from outside our universe - ie. outside our 4 dimensions of time and space, so he/she/it will burst in to existence in a sudden event that will cause a severe disturbance of the fabric of space-time, which can trigger events on a cosmological scale, so how about a nearby gamma ray burst? According to Wikipedia, "a typical ...


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Coronal Mass Ejection A coronal mass ejection (CME) can be devastating. Although CMEs like the Carrington Event would not directly result in a loss of life, but could knock out all electricity across the entire planet, which could have taken up to a decade and $2.6 Trillion USD to recover from, there's no saying that CMEs can't be larger. An even larger ...


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Assuming that the defensive layers were built out from our world with each more distant layer adding to the security provided by the closer, earlier constructed layer, then the closest layer (the one which falls) would be the oldest layer. It would have been constructed at a time when the deity's influence on the planet was higher than it has subsequently ...


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When I look through history, the deadliest natural disasters are region specific, them being earthquakes, floods, etc. This is probably because you were looking at the wrong things. The first thing off the top of my head would be a major volcanic event. You've probably looked at these, glanced at the scope of the destruction from the eruption and immediate ...


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A sufficiently large volcano would (and has done, many times) have the result you're talking about. A volcanic eruption in 1815 caused severe climatic and agricultural effects worldwide for more than a year. The eruption dumped tons of fine volcanic dust into the stratosphere that reduced sunlight and affected temperatures and rainfall across the globe. ...


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How about a meteor strike? Something a little smaller than the 11 to 81 kilometres that was the Chicxulub crater would still do immense worldwide damage. Or how about a large volcanic eruption like Krakatoa? Depending where it happened, you could get direct and indirect effects such tsunamis. Finally, there's always a Megatsunami, such as the canary ...


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Maybe a small Oort cloud object falls in towards the inner solar system and is disrupted by a close encounter with Jupiter on the way. The debris swing around Jupiter and are directed at Earth which is just at the wrong place at the wrong time. Hundreds of large rocky and icy objects impact across Earth, some burning up, some making relatively small craters ...


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Well, the story can't be literally true. A continent the size of Australia will not fit "within the straits of Gibraltar", because its area, of almost three million square miles, is several times larger than the entire Mediterranean Sea, which is just under a million square miles. However, there is an event in the ancient past that could explain all of this....


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You could potentially get away with destroying a larger city with a smaller meteor if you took advantage of a knock on effect from something else being destroyed. An example of this: A very large dam upstream of the city is destroyed by the meteor, causing a catastrophic flood that washes most of the city away.


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As long as the creature weighs less than the liquid it displaces, it will float. You can take a material of arbitrarily high density and craft something that will float, so long as you make its volume large enough. Metal ships are made of material that's much denser than water, but they're designed to have a large cavity inside so that they displace a lot of ...


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As noted, Barringer (Meteor) Crater provides an easily observable benchmark: a 1.2 km crater would be the result of an explosion large enough that you could assume everything within tens of kilometers would be flattened, and right there is even a very large modern city. For another comparison, Tunguska. The airburst was somewhere between 10 and 30 ...


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Something like the Tunguska event might be suitable. I believe directly under the blast trees were left standing so someone in the city in a deep basement might well have survived https://en.wikipedia.org/wiki/Tunguska_event


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A simple idea could be some kind of dense mucus or slime, produced by the creature's glands in its "skin" pores - I'm thinking similar to the mucus in human stomach lining, just on the outside... Might be oversimplifying it but in certain habitats it could work (especially if the use of tools is not too extensive; what do you mean by "work"?) About the ...


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Keep it small First, we need to know the area that must be destroyed: Pompeii covered a total of 64 to 67 hectares (170 acres) and was home to 11,000 to 11,500 people -Wikipedia So you need a radius of total destruction of only about 400 m. That's very small. Second, let's look at the equivalent kind of nuclear detonation will have a 100 % casualty ...


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Let's say something similar in size to Pompeii. This sounds like a job for nukemap. Here's an example detonation of a 15kt yield device, equivalent to the "Little Boy" device used on Hiroshima. The effects of a surface blast are shown, without showing thermal effects which will be quite different for a meterorite impact than for a nuclear explosion. As ...


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House-sized meteor. City-sized crater. A good starting point is the nuclear bomb that dropped on Hiroshima. The blast was city-sized as opposed to country-sized. It had about $6 \times 10^{13}$ Joules of total energy.$^1$ So we know that's not enough for significant secondary effects. We want a meteor with a similar energy total. The kinetic energy of the ...


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I think you can bail out of this problem with an object similar to the one which created the meteor crater Meteor Crater lies at an elevation of 5,640 ft (1,719 m) above sea level. It is about 3,900 ft (1,200 m) in diameter, some 560 ft (170 m) deep, and is surrounded by a rim that rises 148 ft (45 m) above the surrounding plains. Though the crater ...


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