PDA

View Full Version : My Mountains Have Fallen and They Can't Get Up



Porklet
07-02-2011, 06:35 AM
If anyone with knowledge of plate tectonics, vulcanism, and mountain placement can take a look at my work I could really use some feedback. It's a basic map I threw together before I get into terrain, because I can't work out climates until I am sure about my mountains.

I am trying to create (or recreate) a fantasy world I have been working on for quite some time. I redrew my map and as I was working on the climate and currents, etc., I became skeptical that my mountain ranges were feasible. I have included a map below with the basic mountain structure. I was trying to justify the mountain ranges by reverse engineering the tectonics.

I am not certain if any of it is workable. There are a few mountain ranges that I need to be where they are, but I am more concerned with constructing a world that is believable. The brown ranges are the result of tectonic pressure and the orange ranges are the result of vulcanism. I can play with the overall shapes of the ranges. These are not set in stone, no pun intended.

Some information you might need to decipher my gobbledy-goop:

A-E represent the tectonic plates I am proposing.

A1 and A2 are either two separate plates or a single plate. I am leaning towards the latter. I don't believe a plate like A2 could even exist, but I might be wrong.

The area marked 1, yellow, is where plates A and D are puling apart. Or to be more accurate A is moving NW.

Plates C and E have separated from the "Pangea" of A, B, and D. I don't know if this is possible. [NOTE: The fault line for plate D should be to the west of the mountain range on the left and in the water. I didn't realize my mistake until it was too late.]

I also have a question regarding glaciers, since they affect mountain ranges. There was a glacier moving south in the white area marked 2. How far south can it travel? Can a glacier reached the 30th parallel? [Now you know why I included latitudes.]

I apologize if this is confusing. Any feedback regarding the tectonics, mountain placement, and that damnable glacier would be greatly appreciated.

36807

Hai-Etlik
07-02-2011, 08:00 AM
My knowledge of geophysics isn't as good as my knowledge of Geodetics, so I can't give you as much help as with the projection stuff. Of course, you may consider that a good thing ;) Still, this is all just to the best of my knowledge, and I may make some mistakes.

You don't generally get long skinny plates, particularly not with a constricted portion in the middle. Both the continental part of a plate, and plates as a whole, tend to be compact shapes because bits that stick out tend to snap off.

Coastlines generally follow the continental margin fairly closely, but you can have a few deviations to produce "continental" seas (Knowing where your continental margins are would be a big help, continental seas are often great fishing grounds like the Grand Banks). Volcanic arcs are generally produced by subduction of an oceanic plate, so they don't occur far inland and of on a continent, are often mixed with accretion type mountains like the Cascade Volcanoes in the North American Cordillera. The other kind of volcanic arc is produced by a "hot spot" under a moving plate (such as Hawaii) Either way, the volcanoes won't form a dense wall so much as a line of dots.

If you want to place natural barriers, you might consider deserts, barren shield, and other things besides mountains. Mixing your barriers gives you a lot more flexibility. Just a shift in the the local climate or biome can make an effective barrier by simply being different rather than difficult. Even just a river can work, or a lake or inland sea. You also have a lot more flexibility with older mountains than with young ones. The Urals for instance are deep within Eurasia, but are comparatively flat and smooth compared to younger mountains. The Appalachians are another example of a very old range, though they are in a more conventional location.

Islands tend to be hilly or mountainous submerged continent, or oceanic volcanoes. Oceanic volcanoes may be the aforementioned subduction zones (in this case one oceanic plate subducting under another, as with the Aleutian Islands), or Hotspots (Again, Hawaii), Triple Junctions where three plates meet often have particularly large or numerous islands, particularly if the plates are converging. Iceland combines a midocean rift with a hotspot to similar effect.

Hawksguard
07-02-2011, 10:14 AM
What happens with your tectonic plates and the resulting mountain building action is going to depend on a couple factors, most importantly the direction of drift (which in your example, you've only listed A as moving NW, although you do mention that A and D are pulling apart, so I'm assuming D is moving SE.) The other big factor with plate boundaries is whether you are dealing with continental or oceanic crust. Generally plate boundaries fall into one of the following categories:

Rifting Zones, where two plates are moving apart. Magma comes to the surface as "new" land is formed creating mountainous areas. Best examples of this are the mid-Atlantic ridge (longest mountain range on Earth) and the Rift Valley system of eastern Africa.

Sliding Plates, where two plates are moving past each other. You'll get a lot of earthquakes here but not necessarily a lot of mountain building. However, the stress caused by the strike-slip action can have any number of effects on the plates involved, and you can feasibly get isolated areas of volcanism and mountain formation.

Subduction Zones, where two plates ram into each other head on. Again, generally continental crust is going to get thrust upward as the oceanic crust subducts beneath it. As the subducting plate dives into the mantle, the high water content of the oceanic plate causes magma to form at the mantle-crust border. This superheated magma rises, leading to volcanism and mountain building at the surface. This type of mountain building is exemplified in the Pacific Ring of Fire, as well as the Alps and Himalayas. Another type of mountain building associated with this action takes place on continental plates as it "crumples" and uplifts when it goes head to head with a neighboring plate. The Rockies of North America are an example of this action.

Of course, not all mountain ranges need necessarily be at active plate boundaries, even if you are striving for realism. As Hai-Etlik mentioned, you can have hot spots creating volcanic island chains in oceanic plates or supervolcano ranges in continental plates, such as Yellowstone. Some mountain ranges, such as the ancient Appalachians, were created by subduction of tectonic plates that have long disappeared into the mantle. (The modern Appalachians were created through uplift, much like the Rockies.)

So basically I'd keep playing around with your plates, labeling them with different directions, until you get the right combination of mountain-building action. When creating my world I started with the plate boundaries, continental shields and direction of drift and then sketched out the resulting land masses. But there is no reason why you can't do the same thing in reverse.

Your moving glacier does present a bit of a problem. While my expertise on glaciers isn't as thorough as my knowledge of plate tectonics, I will try to offer some observations. While glaciers have the ability to change morphology of mountain valleys, the affect is going to be pretty localized (the longest glacier in the Alps is only about 20 km long). If what you are really talking about here is the expansion of an ice sheet, then that, I suppose, could possibly reach as far south as the 30th parallel, but bear in mind that that's going to be accompanied by major climactic repercussions (and I thought MY world (http://www.cartographersguild.com/showthread.php?15056-Iordanne) was cold). IIRC, the D&D Forgotten Realms world of Abeir-Toril had a huge "glacier" running amok through the center of it, but I believe that was a magically driven phenomena. *Correction: it was a desert running amok, not a glacier, although parts of it did have snow on it. My bad.

Porklet
07-03-2011, 01:14 AM
You don't generally get long skinny plates, particularly not with a constricted portion in the middle. Both the continental part of a plate, and plates as a whole, tend to be compact shapes because bits that stick out tend to snap off.

Coastlines generally follow the continental margin fairly closely, but you can have a few deviations to produce "continental" seas (Knowing where your continental margins are would be a big help, continental seas are often great fishing grounds like the Grand Banks).

I though as much. I am redrawing the plates to be smaller and will combine A2 and C to a degree. When you say "continental seas" do mean when a tectonic plate that contains both land and a significant portion of an ocean?

I am going to have to work on the plates involved with the major continent first. Many of the islands you see have not been dealt with, and they are supposed to be volcanic in origin (as you might have guessed). I will consider what you and Hawksguard have said and repost a new map tomorrow. I just got home and have to be back at work in less than 7 hours. Keeping the major plates in place but breaking them down into smaller components might be the best alternative.

In regards to the barriers you mentioned. The area south of the mountains on the northern reaches of D is an expansive savannah and large portion that resembles the Kalahari desert. it's already a formidable barrier. I am not so concerned with how impassable the mountains are just as long as they create a rain shadow.

EDIT: I forgot to thank you for your help. Thanks.

Porklet
07-03-2011, 01:21 AM
Of course, not all mountain ranges need necessarily be at active plate boundaries, even if you are striving for realism. As Hai-Etlik mentioned, you can have hot spots creating volcanic island chains in oceanic plates or supervolcano ranges in continental plates, such as Yellowstone. Some mountain ranges, such as the ancient Appalachians, were created by subduction of tectonic plates that have long disappeared into the mantle. (The modern Appalachians were created through uplift, much like the Rockies.)

So basically I'd keep playing around with your plates, labeling them with different directions, until you get the right combination of mountain-building action. When creating my world I started with the plate boundaries, continental shields and direction of drift and then sketched out the resulting land masses. But there is no reason why you can't do the same thing in reverse.

Thanks in advance for your help. I get what your saying, but I just need to clarify a few terms:

What are plate boundaries (I am assuming the edges of the plates, but I want to be certain)?
What are continental shields?
Direction of drift seems to be self explanatory and would tell me what type of activity I would have where the plates met.

As I posted above to Hai-Etlik. I am moving towards breaking down the plates into smaller ones. This would allow for some of the vulcanism in the southern oceans that inevitably needs to take place and still allow for some actvity with mainland. I will work on it tomorrow and repost. As I posted I have to go back to work. Time for some Z's.

Hai-Etlik
07-03-2011, 03:13 AM
I though as much. I am redrawing the plates to be smaller and will combine A2 and C to a degree. When you say "continental seas" do mean when a tectonic plate that contains both land and a significant portion of an ocean?

There are two kinds of crust that make up the plates. The thick but relatively light continental plate, and the thinner but much denser oceanic plate. The oceanic plate is the stuff that fills in the gaps when plates spread apart. Some plates are all oceanic, while others are continental, with bits of oceanic plate hanging off the edges.

Now, all oceanic plate is covered with water except where really tall mountains stick up out of it. Continental plate is mostly above water, but around the edges it drops off a bit and is covered with water. This frill of water covered continent is called a continental shelf. Sometimes a larger area, possibly reaching far inland, is flooded, and that's a continental sea.

At Oceanic-Continental convergent boundaries (where they are coming together) the oceanic plate "subducts" underneath and the ocean floor gets scraped up along the front edge of the continent. There isn't really much of a shelf in this case. The west coast of North America between southern BC and northern California (the Cascadia Subduction Zone) is a clear example of this. It has multiple parallel chains of mountains, frequent earthquakes, occasional MASSIVE ones, and volcanoes mixed in with the mountains.

At Oceanic-Oceanic convergent boundaries, you get similar subduction, but instead of mountains, you get a deep trench, and then a chain of volcanoes behind that which may reach up to form islands. Earthquakes are the same as for subduction under a continent: frequent, and occasionally huge.

Continental-Continental boundaries result in both being forced up into HUGE mountains. Without the subduction, you don't get the volcanoes or the really big earthquakes, though you still get the smaller quakes.

Then there are the crazy complicated parts like the Mediterranean basin or the west edge of the Pacific.

Porklet
07-03-2011, 05:42 PM
What happens with your tectonic plates and the resulting mountain building action is going to depend on a couple factors, most importantly the direction of drift (which in your example, you've only listed A as moving NW, although you do mention that A and D are pulling apart, so I'm assuming D is moving SE.) The other big factor with plate boundaries is whether you are dealing with continental or oceanic crust. Generally plate boundaries fall into one of the following categories:

Rifting Zones, where two plates are moving apart. Magma comes to the surface as "new" land is formed creating mountainous areas. Best examples of this are the mid-Atlantic ridge (longest mountain range on Earth) and the Rift Valley system of eastern Africa.

Sliding Plates, where two plates are moving past each other. You'll get a lot of earthquakes here but not necessarily a lot of mountain building. However, the stress caused by the strike-slip action can have any number of effects on the plates involved, and you can feasibly get isolated areas of volcanism and mountain formation.

Subduction Zones, where two plates ram into each other head on. Again, generally continental crust is going to get thrust upward as the oceanic crust subducts beneath it. As the subducting plate dives into the mantle, the high water content of the oceanic plate causes magma to form at the mantle-crust border. This superheated magma rises, leading to volcanism and mountain building at the surface. This type of mountain building is exemplified in the Pacific Ring of Fire, as well as the Alps and Himalayas. Another type of mountain building associated with this action takes place on continental plates as it "crumples" and uplifts when it goes head to head with a neighboring plate. The Rockies of North America are an example of this action.

Of course, not all mountain ranges need necessarily be at active plate boundaries, even if you are striving for realism. As Hai-Etlik mentioned, you can have hot spots creating volcanic island chains in oceanic plates or supervolcano ranges in continental plates, such as Yellowstone. Some mountain ranges, such as the ancient Appalachians, were created by subduction of tectonic plates that have long disappeared into the mantle. (The modern Appalachians were created through uplift, much like the Rockies.)

So basically I'd keep playing around with your plates, labeling them with different directions, until you get the right combination of mountain-building action. When creating my world I started with the plate boundaries, continental shields and direction of drift and then sketched out the resulting land masses. But there is no reason why you can't do the same thing in reverse.

Your moving glacier does present a bit of a problem. While my expertise on glaciers isn't as thorough as my knowledge of plate tectonics, I will try to offer some observations. While glaciers have the ability to change morphology of mountain valleys, the affect is going to be pretty localized (the longest glacier in the Alps is only about 20 km long). If what you are really talking about here is the expansion of an ice sheet, then that, I suppose, could possibly reach as far south as the 30th parallel, but bear in mind that that's going to be accompanied by major climactic repercussions (and I thought MY world (http://www.cartographersguild.com/showthread.php?15056-Iordanne) was cold). IIRC, the D&D Forgotten Realms world of Abeir-Toril had a huge "glacier" running amok through the center of it, but I believe that was a magically driven phenomena. *Correction: it was a desert running amok, not a glacier, although parts of it did have snow on it. My bad.


I have revamped the make-up of the world, and I have included a new map with plates and drift. The drift is not exact as I used my air current arrows as a brush so I don't have one that points SE. It will show, however, basic movement towards/away adjacent plates.

Mountains: Light Brown represents new mountain formations that are still growing, Brown represents middle-aged mountain ranges, and the Dark Brown ranges are ancient. The red circles represent Hot Spots. I am not sure if I have way too many. There might be some areas where more volcanic activity might occur, and I am certain that the convergence of plates B, C, and H might have more upheaval. If you could point out areas where quakes or volcanoes would be prevalent feel free to point it out. If you have any other ideas please share them.

Damn the glacier, and full speed ahead!

I had noted your world map already. I believe it came up as a random gallery on the homepage just a few days ago. Although, I might have run across it looking at the work of others here. It looks very natural to me, and I like the feel of it.

Thanks again.36824

Porklet
07-03-2011, 05:48 PM
Islands tend to be hilly or mountainous submerged continent, or oceanic volcanoes. Oceanic volcanoes may be the aforementioned subduction zones (in this case one oceanic plate subducting under another, as with the Aleutian Islands), or Hotspots (Again, Hawaii), Triple Junctions where three plates meet often have particularly large or numerous islands, particularly if the plates are converging. Iceland combines a midocean rift with a hotspot to similar effect.

Going back to what you said about Hotspots, I have included a new map in the above post. I have noted Hot Spots in several locations. I do have quite a bit of volcanic activity along plate edges. Is there every a situation where a particular plate is more vulnerable to have Hot Spots (such as plate I in the SW)? I could break it up into smaller plates, but it would be very difficult without producing some plates that simply couldn't exist. Any ideas?

Hawksguard
07-03-2011, 11:42 PM
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
07-04-2011, 02:29 AM
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.36831

Juggernaut1981
07-04-2011, 04:42 AM
Okay, from what you've drawn... (and my moderately better than high-school understanding of the vagaries of plate techtonics)
I'd expect to see a chain of islands potentially occuring between A & B.
B, C & H should be creating some SERIOUSLY tall mountains.
There will be limited mountains between B & D (they're passing plates)
F & I might actually be one plate (they're basically moving together)
F & G won't be likely to have mountains between them.

My thoughts...
I would merge F, G & I into one plate subducting under D & H.
I'd probably have E crashing a little harder into D.

Seems good, but hey feel free to adjust my ideas to better suit yours.

Hawksguard
07-04-2011, 05:21 AM
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
07-04-2011, 08:00 PM
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
07-04-2011, 08:19 PM
Okay, from what you've drawn... (and my moderately better than high-school understanding of the vagaries of plate techtonics)
I'd expect to see a chain of islands potentially occuring between A & B.
B, C & H should be creating some SERIOUSLY tall mountains.
There will be limited mountains between B & D (they're passing plates)
F & I might actually be one plate (they're basically moving together)
F & G won't be likely to have mountains between them.

My thoughts...
I would merge F, G & I into one plate subducting under D & H.
I'd probably have E crashing a little harder into D.

Seems good, but hey feel free to adjust my ideas to better suit yours.

When you're in the dark there is no such thing as bad feedback, thanks.

There is an island chain between A & B. You just can't see it, because of my massive red pen stroke when drawing the plate borders.

The mountains between B, C, & H are the home of the gods. The actual home of the gods. No beast or man or man-beast could ever survive there. That's the working theory for the moment, although it isn't final. At least in religious terms it will be considered the home of the gods by some (if not actually). I am going to stop before I confuse myself, again. Aside from that, I want it to be a massive physical and cultural barrier. Mission Accomplished.

The ranges between B & D are the result of previous collision (along with F & G). They are not colliding anymore, but the ranges remain. I am toying with removing some ranges and making them fit better. See my reply above to Hawksguard for more details, if you want.

I am not opposed to combining F & I. Whatever the case I need to fix the border between F & G and remove that concave portion. I don't think a plate of that shape could exist. I might be wrong. I'll toy around with it when I fix F.

Noted above, F & G were once colliding (along with B & D). They have since divorced, and they have joint custody of the kids, er, mountain ranges. F & D were colliding together with at least G (if not B & G); in theory.

I need the mountains along G (created by previous collision with F). If I combine F, G, and I...I won't get the mountains there that I want. The problem is I am reverse engineering the plate tectonics to match a mountain configuration that was already in place. I have made significant changes already, but I don't want to sacrifice too much of the original.

You are absolutely right about D and E. The original design of the land mass on D was basically a circle of mountains (not really but close enough to be impossible under natural law). I wanted mountains along as many sides as possible there. I can't believe I missed that opportunity. Thanks. I'll repost a fix below. Thanks again, again.

Porklet
07-04-2011, 09:28 PM
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
07-04-2011, 09:35 PM
Here is the image. It would not let me insert it online, for whatever reason. Sorry about that.

36888

Hawksguard
07-04-2011, 11:41 PM
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 (http://volcanoes.usgs.gov/images/pglossary/vei.php). 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).

Hawksguard
07-04-2011, 11:45 PM
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.

Porklet
07-05-2011, 04:43 PM
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.

I don't necessarily need a mini-ice age. I figured an explosion massive enough to bury a, albeit small, civilization might have wide ranging effects. As long as the Acrilotian people are scattered throughout the southern seas as a result of the eruption I am satisfied. I'll toy around with the global effects, if any, later. I saved your VEI post in Notepad for future reference. You've been very helpful.
Entirely Plausible is absolutely acceptable to me. Consider yourself thanked and Repped.

You wouldn't happen to be a climatologist, would you? Just kidding.

EDIT: Forgot Something

Hawksguard
07-05-2011, 06:54 PM
You've been very helpful.
Entirely Plausible is absolutely acceptable to me. Consider yourself thanked and Repped.

You wouldn't happen to be a climatologist, would you? Just kidding.

You're most welcome, I am glad to be of help. And no, hehe, I'm not a climatologist. I do have a rather intense fascination with the forces of nature and have an insatiable curiosity in understanding "how stuff works," so I'm always looking for new things to learn and how to apply them to my creations. Map making, even the fantastical variety, for me is as much about history, and economics, and politics, and geology, and climatology as it is about geography.

Porklet
07-05-2011, 07:33 PM
You're most welcome, I am glad to be of help. And no, hehe, I'm not a climatologist. I do have a rather intense fascination with the forces of nature and have an insatiable curiosity in understanding "how stuff works," so I'm always looking for new things to learn and how to apply them to my creations. Map making, even the fantastical variety, for me is as much about history, and economics, and politics, and geology, and climatology as it is about geography.

Very true. I have worked extensively on the cultures, religions, history, etc. of the world, but I have only recently begun to create a concrete physical world to put them in. I've always had hand drawn maps that changed over the years, but I wanted something more substantial so that I could explore its progression. I have to place the mountains, and then I am going to work on the air and water currents and rainfall. Once I get a first draft set-up I am going to post. I'd love to get your feedback.

cantab
07-10-2011, 02:59 AM
You've got the basics right. A maximum of three plate boundaries meet at a point, which is correct, and it's nice to see hotspots taken into account.

A first tip: colour-coding your boundaries depending on whether they're ridges, trenches/collisions, or transform/strike slip faults will make the map easier to interpret.

Can I assume your reference frame - the thing that you consider "still" and measure your plate motions from - is the hotspots? (A sensible choice.)

A few points:

If you're going to show plate boundaries in your final map, you may want to think about their shapes. Ridges in particular have a distinctive "stepped" shape, as segments of ridge proper are offset by transform (strike-slip) faults. You can see that here: http://www.mnh.si.edu/earth/text/4_3_1_0.html The ridges should be at right-angles, and the transforms parallel, to the plate motion.

Trenches can be straight, they can follow a continental edge, or they can have an arced shape with the subducting plate on the convex side. It's OK to have quite oblique subduction.

Transform faults are typically straight. They can have bends in them though. These bends give either "pull apart basins" or "push up mountains". You have an example of the latter on the B-D boundary.

You could eliminate the F-I boundary. If you keep it, either make one plate moving faster, or make it a very slowly spreading ridge. (Subduction zones don't tend to go slowly). Similar for A-E.

You have more large transform boundaries than are on Earth. (I have the same issue with my own WIP tectonics-based map.) The E-F, F-G, and G-K boundaries in particular seem a bit strange. However, if you meet either of the two "growing" cases here: http://en.wikipedia.org/wiki/Transform_fault#Transform_fault_types then you can justify those big transforms.

A plateau somewhere next to the B-C-H mountain range wouldn't be unreasonable (much like the Tibetan plateau).

I might expect some clearer island chains from hotspots (like the famous Hawaii chain). Not all hotspots produce such neat chains, but many do. The biggest island, and the volcanically active one, is over the hotspot, with progressively older and (generally) smaller islands extending away in the direction of the plate's motion.