My Mountains Have Fallen and They Can't Get Up

[Hawksguard]

What are plate boundaries (I am assuming the edges of the plates, but I want to be certain)?
What are continental shields?

The question about plate boundaries I'm pretty sure has been answered, but just to reiterate, they are indeed the edges of the plates, whether or not they are actually "active". Continental shields are large areas of continental crust that are known for their geological stability, and are usually located far from plate boundaries. Created during the Precambrian, they represent the oldest rocks on the Earth's surface. Some examples of shields are northeastern Canada & Greenland, Western Australia, the Amazon Basin, and the Baltic area.

Thanks for the compliments on my own world-in-progress. I take a lot of time and effort and study to make sure I'm getting my science down correctly and make sure there are no glaring holes that would "suspend disbelief", as it were.

In regard to your question about hotspots, bear in mind that hotspots are not a function of tectonic action -- it is tectonic action that makes them easily identifiable. The technical term for a hotspot is "mantle plume", and as the name would suggest, the mechanism that creates them has its origin deep in the mantle of the earth. Mantle plumes DON'T move...the tectonic plate above it does. As a result, you get a new volcano to form over the plume head when tectonic action moves the plate far enough. Since mantle plumes are not caused by tectonic forces, they can occur anywhere and in fact are most easily identifiable when they happen in the middle of a plate, like Hawai'i or Yellowstone, where there is no logical reason for geologic activity to be taking place there. If you have a planet that is geologically active, it would make sense for them to be "popping up" all over.

Another thing I would also suggest is don't overthink it. It is easy to get caught up in being scientifically accurate, but there comes a point when you become bombarded by too much science and it all becomes meaningless drivel. Looking at your most recent map, I would observe that there is no immediately apparently reason why there should be mountains between B & C, or F & I, or H & L, since these pairings illustrate neighboring plates moving in the same direction. However, the main force(s) causing plate tectonics is by no means constant. Plate W may have moved at rate X in direction Y for Z million years, but any one of those variables could change at anytime.

The bottom line is once you've got your scientifically plausible geosphere, all pretty and polished with a high glossy sheen, don't be afraid to totally obliterate it if the story you are trying to tell through your map says 'It Must Be So."

[Porklet]

The question about plate boundaries I'm pretty sure has been answered, but just to reiterate, they are indeed the edges of the plates, whether or not they are actually "active". Continental shields are large areas of continental crust that are known for their geological stability, and are usually located far from plate boundaries. Created during the Precambrian, they represent the oldest rocks on the Earth's surface. Some examples of shields are northeastern Canada & Greenland, Western Australia, the Amazon Basin, and the Baltic area.

Thanks for the compliments on my own world-in-progress. I take a lot of time and effort and study to make sure I'm getting my science down correctly and make sure there are no glaring holes that would "suspend disbelief", as it were.

In regard to your question about hotspots, bear in mind that hotspots are not a function of tectonic action -- it is tectonic action that makes them easily identifiable. The technical term for a hotspot is "mantle plume", and as the name would suggest, the mechanism that creates them has its origin deep in the mantle of the earth. Mantle plumes DON'T move...the tectonic plate above it does. As a result, you get a new volcano to form over the plume head when tectonic action moves the plate far enough. Since mantle plumes are not caused by tectonic forces, they can occur anywhere and in fact are most easily identifiable when they happen in the middle of a plate, like Hawai'i or Yellowstone, where there is no logical reason for geologic activity to be taking place there. If you have a planet that is geologically active, it would make sense for them to be "popping up" all over.

Another thing I would also suggest is don't overthink it. It is easy to get caught up in being scientifically accurate, but there comes a point when you become bombarded by too much science and it all becomes meaningless drivel. Looking at your most recent map, I would observe that there is no immediately apparently reason why there should be mountains between B & C, or F & I, or H & L, since these pairings illustrate neighboring plates moving in the same direction. However, the main force(s) causing plate tectonics is by no means constant. Plate W may have moved at rate X in direction Y for Z million years, but any one of those variables could change at anytime.

The bottom line is once you've got your scientifically plausible geosphere, all pretty and polished with a high glossy sheen, don't be afraid to totally obliterate it if the story you are trying to tell through your map says 'It Must Be So."

Although I have dreaded taking this step you have made it much easier for me, and I thank you. I do not want to overthink it. However, I have changed the direction of B to work against C since I do want the largest mountains in the world to be in that area. That being said I am almost satisfied with it, but I do have a couple of questions if you don't mind.


1. Are plates moving away from each other more likely to have volcanic activity? Thinking this was the case I did not place Hot Spots along plates G & I, G & J, and H & K.
2. You refer to F & I and H & L, but I don't have any mountains there. Could you mean the mountains along the sea between D, G, and H? Those are remnants of prior collisions. The mountains in the interior are mega-ancient (to coin a term) and are not affected by current tectonic conditions.

I follow you in regards to creating a believable natural world. The history of this world is that is was discovered by the "gods" not created by them. The gods then created men. The natural world was untouched by man or god until this discovery. They can toy with the forces of nature, but they can't break them. I can't truly screw with the nature of things until there is a nature of things.

[Hawksguard]

1. Are plates moving away from each other more likely to have volcanic activity? Thinking this was the case I did not place Hot Spots along plates G & I, G & J, and H & K.
2. You refer to F & I and H & L, but I don't have any mountains there. Could you mean the mountains along the sea between D, G, and H? Those are remnants of prior collisions. The mountains in the interior are mega-ancient (to coin a term) and are not affected by current tectonic conditions.

1. Hmm. Good question. Based on what we see on Earth at diverging plate boundaries, I don't think you are generally going to get the kind of explosive "disaster movie" type volcanism you see from volcanos created in subduction zones like around the Pacific Ring of Fire. But then the mid-Atlantic Ridge, where the North & South American plates are moving away from the Eurasian & African plates, is the longest mountain chain in the world. When measured from the sea floor base, the ridge rises some 15,000 feet. But it's hard to be impressed by mountains (or volcanos) that are mostly hidden beneath another 8,000 feet of water.

And again, as far as the hotspots go, you can really put them anywhere, they don't need to be near plate boundaries.

2. I think I lost my train of thought briefly when I was taking about your plates and just got focused on what direction they were going. I was comparing the three sets because the pairs were moving in unison but, as you say, there weren't any mountains between two of the pairs, as there right oughtn't to have been. So, Kudos for you. My bad for the confusion. /smack

B, C & H coming together should develop a very high mountain range. However, since all you're dealing with here is continental crust (not as dense or high in water content as oceanic crust), there probably won't be a lot of volcanos, just really really huge mountains (like the Himalayas). If volcanos are a must-have you could stick a deep inland sea in there somewhere next to where the mountains are forming, it being the last remnant of some ancient ocean soon to disappear forever (like the Mediterranean).

[Porklet]

1. Hmm. Good question. Based on what we see on Earth at diverging plate boundaries, I don't think you are generally going to get the kind of explosive "disaster movie" type volcanism you see from volcanos created in subduction zones like around the Pacific Ring of Fire. But then the mid-Atlantic Ridge, where the North & South American plates are moving away from the Eurasian & African plates, is the longest mountain chain in the world. When measured from the sea floor base, the ridge rises some 15,000 feet. But it's hard to be impressed by mountains (or volcanos) that are mostly hidden beneath another 8,000 feet of water.

And again, as far as the hotspots go, you can really put them anywhere, they don't need to be near plate boundaries.

2. I think I lost my train of thought briefly when I was taking about your plates and just got focused on what direction they were going. I was comparing the three sets because the pairs were moving in unison but, as you say, there weren't any mountains between two of the pairs, as there right oughtn't to have been. So, Kudos for you. My bad for the confusion. /smack

B, C & H coming together should develop a very high mountain range. However, since all you're dealing with here is continental crust (not as dense or high in water content as oceanic crust), there probably won't be a lot of volcanos, just really really huge mountains (like the Himalayas). If volcanos are a must-have you could stick a deep inland sea in there somewhere next to where the mountains are forming, it being the last remnant of some ancient ocean soon to disappear forever (like the Mediterranean).

Cool. Cool. Cool. I don't need volcanoes along the plates I mentioned. The islands along those seams resemble the types of island chains you might get from vulcanism, but they don't necessarily need them.

I hadn't given much thought to volcanoes along the massive wall of mountains between B, C, & H, but the idea of an inland sea is intriguing. When I decided to recreate the map I almost doubled it's size, and that left a lot of new area to fill. That is a phenomena I was unfamiliar with, thanks.

Just one more quick question. When I look at how D and F collided with B and G to form the mountains along the straits in the west it seems that they don't match up to well. I was thinking of eliminating the mountains on B and D (or converting them to ranges of a more ancient origin), and making the ranges on D, F, and G fit together better. Or do you think the passage of time and several course changes between the four plates could account for that configuration of mountain ranges? I have included the map below for your convenience.

Edit: Removed map, see post below.

[Porklet]

I have included the fixes that I noted earlier. I straightened out the border between F and G. I included another range between D and E. I made the ranges bordering B and D more ancient, or ancienter. I also filled out the ranges along D, F, and G so that fit together better. Let me know what you think.

As a side note, the Hot Spot in the bottom left hand corner (the smaller one) was once the site of a massive volcanic eruption, similar to Krakatoa. It destroyed the civilization that was centered there centuries ago. It created a mini-ice age similar to the one we experienced around a 1,000 years ago. My question is, what would a massive volcanic eruption do to the surrounding islands and major land masses? Tidal waves? Accompanying earthquakes? I am curious to know.

I could not get the image uploaded. I will try again soon.

[Porklet]

Here is the image. It would not let me insert it online, for whatever reason. Sorry about that.

[Hawksguard]

And I forgot to mention, your most recent map is looking good. Nothing huge that jumped out at me that needed an overhaul. I'd stick it in the "entirely plausible" category.

[Hawksguard]

As a side note, the Hot Spot in the bottom left hand corner (the smaller one) was once the site of a massive volcanic eruption, similar to Krakatoa. It destroyed the civilization that was centered there centuries ago. It created a mini-ice age similar to the one we experienced around a 1,000 years ago. My question is, what would a massive volcanic eruption do to the surrounding islands and major land masses? Tidal waves? Accompanying earthquakes? I am curious to know.

The extent of physical damage that volcanos are capable of causing depends entirely on its Volcanic Explosivity Index. For most volcanic eruptions in recent history, the primary damage tends to be fairly localized. Of course secondary effects like tidal waves can have serious consequences for population centers far from the actual volcano itself, and things like increased sulfur dioxide in the atmosphere can lead to drops in global temperature.

Your Krakatoa comparison might be a bit weak if you want to induce a mini-ice age. Krakatoa was capable of lowering global temperatures from its eruption, but it only lasted a few years, and not with particularly drastic results. The Krakatoa eruption was a VEI 6. The Tambora supervolcano eruption (VEI 7) was responsible for the "year without a summer" in the Northern Hemisphere in 1815, kicked off a typhoid epidemic in Europe that lasted until the end of the decade, and killed the Indian monsoon season three years running resulting in widespread famine and outbreaks of cholera.

The next order of magnitude up from that would be VEI 8, something like a Yellowstone Caldera supervolcanic eruption, which could bury the western half of North America in inches to feet of ash. You'd have widespread famine, outbreaks of disease, and lowered global temperatures for an extended period resulting in widespread crop failure, desertification, and quite possibly a crippling of political and economic infrastructure. If it were on an island in deep waters, you'd also get huge tsunamis (perhaps megatsunamis).