These are the notes I've made after following [[Following worldbuilding tutorials|Artifexian's GPlates videos]] and [WorldbuildingPasta's guides](https://worldbuildingpasta.blogspot.com/2020/06/an-apple-pie-from-scratch-part-v.html) for making an Earth-like planet. I may have changed the order of doing some things based on what works well for me :D --- ## Setup - Download and install GPlates - Open GPlates - `Edit > Preferences` - Change default start to 2000My - Enable Show topological sections - Check to see if all are enabled under `View > Geometry visibility` - `Window > Show layers` (Ctrl + L) - resize the windows so the main panel and layers panel are accessible - `Reconstruction > Configure animation` - increase frames per second for a faster animation ==this resets when you close and re-open GPlates== - Use the measure tool `S` and change Earth's radius to your own planet's radius (mine is 7434.00km) ==this resets when you close and re-open GPlates== - Make a folder on your PC where your project and files will be saved - Save the project into the folder > [!warning] > If you accidentally input the wrong time and put in a number greater than your oldest point in the timeline, it makes that new time the oldest/start of the timeline. > To fix it go to `Reconstruction > Configure Animation` and change the value in `Animate From:` ## Cratons - Set the timeline to the beginning (2000 Ma) - Draw 8-12 cratons (not spread too far apart) 1. Use the geometry tool `G` to draw 2. Use the measure tool `S` and click two points to measure. Aim for 1,000 to 4,000 km in size for each craton and use `Ctrl + K` to remove the measuring line and then press `G` to return to the geometry tool 3. `Create feature > Craton`, Next 4. Plate ID: 100 (the next craton will be 200, then 300, etc) 5. Begin time: distant past enabled 6. End time: distant future enabled 7. Name: Craton A (the next craton will be B, C, D, etc), Next 8. Next 9. Select `Create a new feature collection`, Create and save 10. On the `Manage Feature Collections` window (Ctrl + M), save the new feature collection into your project's folder as file name: `cratons` 11. 12. Repeat steps 1-7 above for the other cratons, but instead on step 8 select your `cratons.gmpl` and then click Create 13. In the `Layers` window, toggle down the cratons layer and enable `Fill polygons` and reduce the opacity as desired 14. Open the `Manage Feature Collections` window (Ctrl + M), save all changes 15. `File > Save project` I went with 10 cratons and I find it handy to have a list of their colours so it's easier to identify and remember (even though I can click on them, too). | Craton name | ID | Colour | | ----------- | ---- | ---------- | | Craton A | 100 | cyan | | Craton B | 200 | dark green | | Craton C | 300 | magenta | | Craton D | 400 | grey-blue | | Craton E | 500 | lime green | | Craton F | 600 | indigo | | Craton G | 700 | red | | Craton H | 800 | orange | | Craton I | 900 | peach | | Craton J | 1000 | dark blue | ## Supercontinent ==I found it easier to draw the supercontinent shape & measure it first, then put the cratons on top== - Draw a supercontinent shape around the cratons 1. Use the geometry tool `G` to draw 2. Aim to have between 25-50% global coverage (closer to 25% is ideal) - Use the measure tool `S` and take note of the area size in km² - Your coverage percentage is the area size of the continent divided by the surface area of the planet =ContinentArea/(4\*3.14\*PlanetRadius^2) Mine looks like this: `=176785479.8541/(4*3.14*7434^2)` and I got `0.25` meaning my continent covers 25% of the planet - Adjust the continent shape as needed and remeasure until you're happy with the result. If you can't make a shape small enough around the cratons, edit the size and shapes of the cratons or redraw them a bit closer together 3. `Create feature > Continental crust`, Next 4. Plate ID 100, created in distant past, continues to distant future, name: Continent ABCDEFGHIJ, Next 5. Next 6. Create new feature collection, create and save 7. Save new feature collection as `continents` 8. Save project ![[Pasted image 20240523215324.png]] ## Image raster overlay - Using image editing software of choice, create a 1000px by 500px horizontal canvas, fill it with green and export it as `land.png` in your project folder - Fill the same canvas with blue and export it as `ocean.png` in your project folder - Back in GPlates, `File > Import > Import Raster`, select the land.png - Next, Next, Finish - Toggle down the land layer, add new connection to reconstructed polygons, select continents and later add island arcs - set those to have no fill and have the style as plate ID - Do the same for ocean and hide the layer (eye) until you need to add oceanic plates - Optionally you can make one for cratons too - Rename layers so it's clear they are feature colours e.g. `land colour`, `ocean colour` > [!warning] > If a continent size is too big the image raster won't show until it's either made smaller or rifted apart. To test this, make a new continent that is just a ## Continental rift - `L`, draw a rift through the continent (avoiding cratons) - Create feature > Continental rift, Next - Plate ID 1, name Rift 2000, starts at 2000, ends distant future, Next - Next, Create new feature collection, Create and save - Save new feature collection as `rifts` - Set draw style of rifts layer to single colour red - Save project For future continental rifts, name them after the time they start at and save them into the rifts feature collection. ### Turning a failed rift into a full rift - Select the failed rift - Copy geometry to digitize tool - Use the line tool `L` and insert nodes `I` until it severs the entire plate (from subduction zone to end of oceanic crust), press `L`, create feature - Same creation instructions as a continental rift but with relevant timestamp ## Failed rifts - Same process as a continental rift except it needs to have the Plate ID of the nearest craton and name it Failed Rift and the time it started - Belongs in a feature collection for failed rifts (set colour as silver) ![[Pasted image 20240523215410.png]] ## Splitting continent ### Setting up topology boundaries (Following [latest](https://www.youtube.com/watch?v=CxFpWyAzWqw) Artifexian video using topology) - Select continent - Copy geometry to digitize tool - `L` to turn it into a line - `X` to delete verteces until you're left with one coastline of the section you want to cut out, with a bit of overlap beyond the rift - `L`, create feature, unclassified feature - Plate ID matching the craton - Set start date, end distant future, name `Line` - Next, Next, New feature collection, create & save as `Guides` - Set draw style for guides black - Do the same but for the other half of the continent - Topology menu `4`, build new boundry topology `B` - Select one of the Lines and click add, select the rift and add - Create > TopologicalClosedPlateBoundary, Next - Plate ID matching the line you selected, matching start/end time, name `Topo`, Next - Next - New feature collection create and save called Topo - Repeat for other half of the continent - Select one of the Topo for a half of the continent - Copy geometry to digitize tool, create feature, continental crust (with the correct ID and start/end times), name it after the cratons it contains e.g. Continent ABCF, save into continents - Select the same topology again and delete it - Repeat for the other half of the continent - Select the original unsplit continent and edit the end date - put it as the start date of the new split pieces - Save all changes in manage feature collections `Ctrl + M` and also save project > [!warning] > Carefully observe when deleting verteces and make sure the "gap" part of the line is by the rift otherwise it won't connect properly. You may need to redraw some parts to get it in the right place. > [!info] Reminder > When splitting a continent, everything needs to be split including: continent, island arcs, ocean crusts, guide lines, and subduction zones. They all need to have a plate ID matching the newly split continent, same for the other half. > > Ocean crust > clone twice > assign ids to each half > delete original > > ==check ocean age data is preserved by changing ocean poly fill to age (and turn off raster)== >[!quote] >Changing the plate ID of an existing feature causes it to inherit the rotation pole and characteristics of the new plate. If the two plates are different from one another and have different poles and coordinates it'll jump. Instead of changing the ID you can create a temporary "burner" crust piece with a plate ID of "0" then copy the points and make a new crust piece with your new plate ID from scratch. As long as it's a new feature and not changing the ID of an existing feature it shouldn't jump. It's extremely tedious, though. >- crackdtoothgrin ### Setting up a rotation file - Open a plain text editor like Notepad++ and make a new file First number: plate ID Second number: timestamp Next three numbers: coordinates Final 3 digits: conjugate plate ID (the plate ID it's following, 000 is independent) Everything after `!` is a comment ![[Pasted image 20240523215410.png]] - Link them up based on the two halves of the continent being split (for me it's all the top half ones follow 100, bottom half all follows 800) - Save the file in your project folder as `rotation.rot` ```rot 100 0.0 90.0 0.0 0.0 000 ! Craton A cyan end 100 2000.0 90.0 0.0 0.0 000 ! Craton A cyan start 200 0.0 90.0 0.0 0.0 100 ! Craton B dark green end 200 2000.0 90.0 0.0 0.0 100 ! Craton B dark green start 300 0.0 90.0 0.0 0.0 100 ! Craton C magenta end 300 2000.0 90.0 0.0 0.0 100 ! Craton C magenta start 400 0.0 90.0 0.0 0.0 100 ! Craton D grey-blue end 400 2000.0 90.0 0.0 0.0 100 ! Craton D grey-blue start 500 0.0 90.0 0.0 0.0 100 ! Craton E lime green end 500 2000.0 90.0 0.0 0.0 100 ! Craton E lime green start 600 0.0 90.0 0.0 0.0 100 ! Craton F indigo end 600 2000.0 90.0 0.0 0.0 100 ! Craton F indigo start 700 0.0 90.0 0.0 0.0 100 ! Craton G red end 700 2000.0 90.0 0.0 0.0 100 ! Craton G red start 800 0.0 90.0 0.0 0.0 000 ! Craton H orange end 800 2000.0 90.0 0.0 0.0 000 ! Craton H orange start 900 0.0 90.0 0.0 0.0 800 ! Craton I peach end 900 2000.0 90.0 0.0 0.0 800 ! Craton I peach start 1000 0.0 90.0 0.0 0.0 800 ! Craton J dark blue end 1000 2000.0 90.0 0.0 0.0 800 ! Craton J dark blue start ``` - Manage feature collections `Ctrl + M`, open file, open the rotation.rot file - Save any changes and save the project ## Decoupling cratons - Save all changes - Open rotation file in text editor - Copy the last entry for the plate you want to move independently and paste it one line above - Change the time of the new line to the rifting event - Change comment to "End following (craton name)" - Copy that new line and paste it one line above - Change the comment to "Start moving independently" - Change the conjugate plate ID to 000 - Without saving, go into GPlates, go to time of rifting, `Ctrl + P`, Equivalent Rotations, look for the plate ID of the one that needs to move and copy those coordinates into the rotation file on the start moving independently line - Copy that line and paste once above, change the comment to "Drift correction" and set the time to `1.0` - Make sure any neighbouring cratons are also following the newly independent craton *(might not be necessary to add new lines at least for the first/second split)* - Save the file and refresh the rotation file in GPlates - Test if it works ## Moving plates - After splitting a continent skip ahead 50 Ma in the timeline (e.g. from the start at 2000 to 1950) - Pole manipulation tool `5`, choose a feature `F` and select one half - Move pole `O` and enable pole manipulation - Modify reconstruction pole `P` and enable highlight children - Use the `O` and `P` tools to move the pole and continent into place - Appy the rotation and click OK - Kinematics tool `Ctrl + Shift + K` - input plate ID of the continent you've just moved - input the start/end times of measuring - select `velocity magnitude` - click update - Re-adjust location of the continent and check kinematics again, checking that the speed matches the situation - Once happy save all changes and project - Repeat for any other continents that need to move - Continue to drift correction | Situation | Example | Plate speed (cm/year) | | --------------------------- | --------------------- | --------------------- | | Subducting ocean | Old India | 8-20 | | Recent subduction collision | Current India | 6 | | Active margin continent | Current South America | 3 | | Passive margin continent | Current Africa | <1 | ### Drift correction - Make sure all changes are saved - Open the `rotation.rot` file in a text editor - For the plate IDs of the continents you just moved: - If doing this for the first time: - Copy the latest line (it should be the line underneath `0.0`) - Paste it above itself - Replace the time and change it to `1.0` and add a comment of `Drift correction` - If it's not the first time doing it: - Replace the coordinates and conjugate ID of the drift correction line with that of the latest entry - Save the .rot file - Back in GPlates open Manage Feature Collections `Ctrl + M` and refresh the rotation file - Run the animation and if done correctly the continents will remain in place after they've finished moving - Save all changes and save project - Check to see if flowlines need repairing ## Flowlines - Go back to the time of rifting - Select the rift, copy geometry to digitize tool, `M`, create feature, flowlines - left plate ID = one half, right plate ID = the other - start time = time of rifting - end time = 50 Ma later than rifting - name = Flowlines start-end dates e.g. `Flowlines 2000-1950`, Next - Add, From: time of rifting (2000) To: next timestep (1950), Insert, OK, Next - Create new feature collection or put in existing flowlines collection > [!warning] > Check carefully to see if any flowlines are twisting / crossing over each other or overlapping continents. Re-adjust or re-do continent movements where necessary. > [!tip] > "...they should never pass over existing sections of crust, except where **subduction** is occurring; as a divergent plate boundary spreads, the flowlines can help you see when it is no longer possible to have spreading along the whole boundary and you need to add a subduction zone." > -- WorldbuildingPasta ### Flowline repair - After drift correction, re-make any broken/misaligned flowlines. Keep the new one and delete the broken one ## Oceanic crust ### Mid ocean ridge (MOR) - Go back to the time of rifting - Select the rift, copy geometry to digitize tool, keep it as a line `L` - Create feature, select MidOceanRidge, Next - Reconstruction method: half stage rotation - Set plate IDs, Start time: time of rifting, End time: distant future, Name: MOR +time of rifting (e.g. MOR 2000), Next - Next - Save into feature collection called Mid Ocean Ridges - Set layer draw style to dark red - Test the timeline to see if it worked ## Triple junction - Add extra parts of each bit of MOR and extend them out - Match them up in the middle of the triangle - `4`, `H` Build New Line Topology - Add the segments that make one long branch of the line - Create MidOceanRidge - Put start time to match the oldest section of line, ends distant future - Name: Divergent - Next, Next, Save into feature collection called Divergent - Move layer to the very top - Set layer style to bright red - Repeat twice more so that all "curves" of the line are covered ### Creating new crust at triple junction - Select one of the new divergent lines - Copy geometry to digitize tool - Delete any weird extra points - `L` create feature, UnclassifiedFeature - By plate ID, name Line, save in Guides - Repeat for each divergent boundary - Skip 50Ma after time of rifting - `4`, `B`, add divergent zone, add the line that hugs the edge of the continent/ocean crust - Create feature, TopologicalClosedPlateBoundary - ID matching continent, matching time, name Topo, save in Topo - Make topo for the other two parts - Select topo, copy geometry to digitize tool, create feature, OceanicCrust - Fill details - Once done, delete all Topo ### Creating oceanic crust - Go back to the time of rifting - Select the MOR (not the rift), copy geometry to digitize tool, keep it as a line `L` - Create feature, UnclassifiedFeature, Next - Reconstruction method: plate ID - Set to one of the continent's IDs, Start time: time of rifting, End time: distant future, Name: Line, Next - Next - Save into guides - Do the same again but put in the other continent's ID - Go 50 Ma ahead from the time of rifting - Topologies `4`, build `B`, select one of the lines and Add, select the MOR and Add, Create - TopologicalClosedPlateBoundary (apparently doesn't matter what choice) - Plate ID matching continent of the line - Start / end times apparently don't matter / keep the same(?), same with the name - Next, Next - Save into topo feature collection - Repeat the process for the other one > [!warning] > I didn't understand *why* I couldn't just choose OceanCrust and skip a step so I did a test to try it out. It ends up making a Resolved Topological Geometries feature collection (like topo), not a Reconstructed Geometries one like the other features (like cratons, continents, etc) and therefore you can't select it on the raster layer (ocean colour) under reconstructed polygons... because it isn't one! > > I'm sure there are likely other things that won't function properly (potentially causing issues with exporting options down the line, too) so I'm going to delete the test by unloading it from the features collection and stick to the tutorial. - Select one of the topo, copy geometry to digitize tool, - Create feature, OceanCrust, Next - Plate ID matching continent - Start time: one timestep after rifting, End time: distant future, Name: Ocean Crust +current time e.g. `Ocean Crust 1950` - Next, Next - Save into ocean crust feature collection - Unhide the ocean colour layer containing the raster image and connect it up - Move the Mid Ocean Ridges layer above the ocean colour layer - Adjust order of other layers so that nothing is being hidden by the oceanic crust - Repeat the process for the other continent's crust - Delete both of the topo as they are no longer needed - Check everything looks good - Save all features, save project > [!warning] Reminder > "You shouldn’t have overlapping sections of ocean crust except where one is subducting under another." > -- Worldbuilding Pasta ## Subduction zones Plate movement is driven by subduction zones. > [!info] Reminder > "Where should subduction zones go? > What movement is caused by them? > What's feeding them?" > -- Artifexian - Watch your timeline a few times and observe the general movement of the continents - Subduction zones should go along the leading edge of the continent - Create the subduction zones at the time of rifting - Use `L` and draw one in > [!tip] > Before you create the feature, check the timeline to see if the main edges of the continent will pass through the line you've just drawn. If they do, the subduction zone will likely have enough pulling power to move the continent (just remember to set the time back to where it was before). - Create feature, SubductionZone, Next - Match plate ID, start time: of rifting, end time: distant future, name: subduction zone - time (e.g. `Subduction Zone 2000`), Next - Next - Save into a feature collection called Subduction Zones - Repeat for the other continent - Save all changes, save project > [!info] Reminder > "One thing to remember about subduction zones is that they don’t only appear when a continent rifts apart or changes direction; If we say that these continents are subducting some of the ocean to their south, then as they move apart that subduction zone will spread along the new ocean’s southern border. So with each timestep, we have to add new sections of subduction zone and island arcs on that boundary." > -- WorldbuildingPasta ## Island arcs For oceanic/oceanic convergent boundaries. They can sometimes attach to the mainland, too. > [!tip] > Draw these in using the orthographic view so they're not distorted near the poles. - 50 Ma after a subduction zone, add island arcs - Use `G` to draw in island arcs as a string of blobs - Create feature, IslandArc, Next - Match plate ID, start: 50 Ma after subduction zone opens, end time: distant future, name: Island Arc -time (e.g. `Island Arc 1950`), Next - Next - Save into a feature collection called Island Arcs - Don't forget to add island arcs to the connections of the land colour layer - Repeat the process for any additional island arcs required - Save all changes, save project > [!info] Reminder > "My rule of thumb is that island arcs form one timestep—**50 My**—after the subduction zone first appears (the one exception is at the very end of the simulation in the last timestep, when even newly formed subduction zones should get small island arcs)." > -- WorldbuildingPasta > [!tip] > Don't zoom in too far when drawing islands at a world map scale. No more than 500% zoom is ideal. | Age | Example | Area Size | | ------- | -------------------------------------------------------------------------------------------------------------------------------------- | ------------------------ | | 50 Ma | [Aleutian Islands](https://en.wikipedia.org/wiki/Aleutian_Islands)<br>[Solomon Islands](https://en.wikipedia.org/wiki/Solomon_Islands) | 17,670 km²<br>28,896 km² | | 100 Ma | [Phillipines](https://en.wikipedia.org/wiki/Philippines) | 343,448 km² | | >100 Ma | [Sumatra](https://en.wikipedia.org/wiki/Sumatra) | 475,807 km² | ### Island arc collisions - Check in 10Ma intervals and stop when the island arc is about half way collided - Check the age of the island arc (=current time-island formation date) - Draw accreted terrane along the contact boundary (scrub through the timeline and note the start/end point length of where the arc passes through) - `S` to measure size - ==\=(length of island arc\*age in Mya)/2 - don't forget age = (creation date - current time) - Create feature ContinentalCrust and give it the ID of the continent it mushed into - Name e.g.`Accreted Terrane 1740` - Save into feature collection called Accreted Terrane - Connect this to the land colour - Set the island arc and subduction zone to disappear at current timestamp - Accreted terrane should be almost entirely covered by a new orogeny ## Orogeny Happens along convergent boundaries. | Conditions | Orogeny Type | Features | Approx Width | | ------------------------------------------------------------------------------- | ---------------------------------------------------------- | -------- | ------------ | | Off shore subduction zone | [Andean](https://en.wikipedia.org/wiki/Andes) | Thin | 200 km | | Rapid subduction and/or <br>when a MOR gets subducted under | [Laramide](https://en.wikipedia.org/wiki/Laramide_orogeny) | Broad | 650 km | | Simple collision between landmasses and/or<br>if one of the landmasses is small | [Ural](https://en.wikipedia.org/wiki/Ural_Mountains) | Thin | 100 km | | Complex, energetic, or BIG continental collision | [Himalayan](https://en.wikipedia.org/wiki/Himalayas) | Broad | 200-400 km | **Andean orogeny on initial supercontinent** - `S` and measure out roughly 100km inland from the coastline - `G` draw in a thin line shape that represents the mountains - `S` to check the width (Andean around 100km wide) - Create feature, OrogenicBelt, Next - Input plate ID, start time, ends distant future, name e.g. `Andean 2000`, Next - Next - Save into feature collection called `Active Orogenies` - In the layer, fill polygons, set draw style, single colour, black, 0.5 opacity - Go forward a timestep and add orogenies as needed - Ignore island arcs (add things in when they collide with continents) - Add orogeny where island arcs are fused with the mainland - Copy geometry to digitize tool and expand it in a new copy rather than adding bits because you'll want to be able to measure things in one piece later - Set any old orogenies to "end" when the new growth begins **Ural orogeny** - If an island arc makes accreted terrane, cover most of the accreted terrane in orogeny **Laramide orogeny** - If subduction is rapid, or most likely if ocean ridge is sucked in **Big collision orogeny** - Orogeny should build up at the border of the collision *after* the continent has been deformed from the collision - For overlapping shapes, split them in halves and make the overlapping part disappear by changing its end date - Skip forward 0.01 in the timeline - Select continent and copy geometry to digitize tool, add a bunch of points and then move them to buckle the continent with a zigzag line over the centre of the overlap - `G`, create feature ContinentalCrust, add details - Select original continent shape, edit details and set end date to rounded timestep - Repeat for second continent side and match up the zigzag line in the middle - Tidy up and trim subduction zones and accreted terrane and guides - One timestep after, set to disappear and set up clone that is in feature collection called old orogeny **Merging** - Parent plate = the one that will do the moving - Save all changes and project - `Reconstruction > Specify Anchored Plate ID` /`(Ctrl + D)` - Input parent plate ID - `Ctrl + P`, equivalent rotations - Open the rotation file - In the child plate ID, find latest timestep and make a line above - Input same ID, time, but put in current coordinates from Ctrl P and put the parent plate ID - Comment "Start following parentname" - Also paste coords into drift correction (make sure conjugate plate ID is the same in drift correction) - Do any other DC - Save rotation file and refresh it in GPlates - `Ctrl + D` - Input `000` - Test to see if you can move the parent plate and have the child follow - For ocean cleanup, copy oceancrust to digitize, hide the overlap part, keep the rest - For Ural and Himalayan orogenies, they are only active at the time of collision because after that they are no longer growing (like with the subduction zone ones) - One timestep after the continents have come together, mark the orogeny as inactive - Copy geometry, create feature, OrogenicBelt, Next - Add in the details - Save into a feature collection called `Former Orogenies` - Move this layer below Active Orogenies - Fill polygons, set draw style, feature age, monochrome (black = new, white = old) - 450 Ma later it will snap back to black for some reason? - Go to the point where it turns black again - Select it, copy geometry, create new feature OrogenicBelt, Next - Change the start/end times but keep the date in the name because that keeps a record of the original event - Save into a feature collection called `Old Orogenies` - Set fill style to single colour white - Select the original active orogeny and set the end time to 50 Ma later ### Orogeny examples From [WorldbuildingPasta](https://worldbuildingpasta.blogspot.com/2020/01/an-apple-pie-from-scratch-part-va.html) | **Location** | **Orogeny Type** | **Width (km)** | | ----------------- | ---------------- | -------------- | | Ecuador | Andean | 80 | | Chile/Argentina | Andean | 120 | | Peru | Andean | 200 | | Chile/Bolivia | Laramide | 750 | | US southwest | Laramide | 1300 | | Russian Urals | Ural | 50 | | Switzerland/Italy | Ural | 180 | | British Columbia | Ural/Andean | 600 | | Nepal/China | Himalayan | 1200 | > [!warning] > Be mindful of where orogenous areas are heading in later stages of moving continents as you may end up with areas that get near- or fully-enclosed in mountains which can lead to inaccessible or very dry areas (which may not be wanted). You can always break it up with a rifting event! ## Large Igneous Provinces (LIPs) [LIP](https://en.wikipedia.org/wiki/Large_igneous_province)s are large areas of sustained volcanic activity. They occur every 10-20Ma in the land or ocean (only simulate land ones). They are shorter events than mountains forming. Due to the massive volcanic activity: - They cause rapid climate changes - They will cause extinctions - They can cause **mass extinction** events (bigger ones are more likely, though not *every* event will cause a mass extinction) Artifexian recommended watching: https://www.youtube.com/watch?v=st_2C_Wrw4A They can be found: - In or around any major rifting events, particularly supercontinent breakup (example: [Central Atlantic magmatic province](https://en.wikipedia.org/wiki/Central_Atlantic_magmatic_province)) - Can also occur randomly For an 850 million year to 1 billion year simulation, aim for 6 - 10 LIPs Active: - Volcanoes, explosive volcanoes, effusive volcanoes, fissure vents - Similar to [Iceland](https://en.wikipedia.org/wiki/Geology_of_Iceland) but much much bigger - Active for 10Ma Inactive (former LIP): - Large plateau of dominantly [mafic](https://en.wikipedia.org/wiki/Mafic) and sometimes [felsic](https://en.wikipedia.org/wiki/Felsic) rock - Similar to [Siberian Traps](https://en.wikipedia.org/wiki/Siberian_Traps) or [Deccan Traps](https://en.wikipedia.org/wiki/Deccan_Traps) - After 450Ma any highland regions will be ground flat ### LIP creation - Go through 50Ma timesteps and decide if you want a LIP to occur - Because the initial supercontinent breakup was so far in the past, avoid the initial breakup - more reasons? - When you've found a large rifting event you want to add a LIP to, step backwards 10Ma in the timeline - `G` and draw in a blob - `S` to measure, area should generally be greater than 100,000 km² and no less than 50,000 km² - `G` create feature, LargeIgneousProvince, Next - Add details, set end time to 10Ma later - Save into feature collection called Active LIP - Set draw style to fill polygons and single colour orange - Go forward to the point where the LIP is no longer active - Select the LIP, copy geometry to digitize tool, if it's spanning a rift, split it and assign the correct IDs to each half, end time continues to distant future, keep the date in the name - Save them as LIPs into a feature collection called Former LIP - Fill orange but set opacity as 0.35 ## Hotspots [Hotspots](https://en.wikipedia.org/wiki/Hotspot_(geology)) are often remnants of or precursors to LIPs. They are isolated volcanic events that occur independently of plate boundaries. They can be on land or in the ocean, seemingly anywhere but with a preference for: - In the middle of old supercontinents - Directly on the opposite side of the globe from supercontinents - In or around rifting events - In any areas where the crust is weak like in regions of slab rollback, in and around MORs, plate triple junctions, or in and around failed rifts They don't last for very long (generally less than 200Ma) and the land it creates doesn't last very long after the hotspot is active. Therefore, ==only add in hotspots in the last 3-4 timesteps (of 50Ma) before your present day.== Add them in increments of 10Ma When they form in the ocean they form island chains (e.g. Hawai'i) in the opposite direction that the plate is moving (leaving a tail of them from the hotspot point). **Before creating hotspots for the first time:** - Open the rotation file in a text editor - Add in two new lines at the very top for plate ID 1 ``` 001 0.0 90.0 0.0 0.0 0.0 000 ! 001 2000.0 90.0 0.0 0.0 0.0 000 ! ``` - Save the file and refresh the rotation file in GPlates **Creating hotspots** - `M`, click one point where the hotspot is, create feature, HotSpot, Next - If there's a cluster, click multiple points near each other - Plate ID 1, lasts into distant future, Next - Save into feature collection called Hotspots - Change draw style to single colour red - Select hotspot, copy geometry to digitize tool, `M`, create feature, MotionPath, Next - Plate ID 1, relative plate ID is the plate that's overriding the hotspot, distant future, call it a Hotspot Trail +timestamp (e.g. Hotstpot Trail 660), Next - Add, from current time to 0, insert, OK, Next - Save into a feature collection called Hostpot Trails - Set draw style to single colour orange - Move the Hotspots layer above the trails ## Topology and plate boundaries > [!quote] > Topology objects are really tricky and labor-intensive to do properly, you kinda just need to spend some time learning the rules for how gplates links objects together to make a topology and then, if you want a continuous animation, go through your history frame-by-frame (i.e. every million years after your start point) and make sure those rules are met for each frame, which often means making multiple topologies for the same boundary to cover different age ranges and adjusting the underlying objects so that they overlap exactly when they should to control a topology passing across them; I'm pretty sure there are points in the gplates sequence I did for artifexian where there are topologies being replaced every frame. > - WorldbuildingPasta ## Set up a new rifting event - Make a failed rift into a new rift (instructions above) - Add new failed rifts - Split the continent and attached features - 50 Ma timestep Repeat processes until ~~the end of time haha~~ you reach the desired result. Check to see what the % coverage of land surface is now, aim for around 30% for Earth-like worlds. --- # Examples from other folks Videos: - https://www.youtube.com/watch?v=0vkFxo8Jn3Y "timeframe is 1000mya-470mya" - https://www.youtube.com/watch?v=D5mSWXrD3Ls Reddit: - https://www.reddit.com/r/mapmaking/comments/10pbxgg/been_fighting_w_gplates_i_think_im_doing_this/ - https://www.reddit.com/r/mapmaking/comments/i98rr6/oc_ive_been_experimenting_with_what_gplates/ - https://www.reddit.com/r/worldbuilding/comments/1713upy/does_a_rift_need_to_go_all_the_way_to_the_mid/ - https://www.reddit.com/r/worldbuilding/comments/16kur59/need_help_with_overlapping_ocean_crust_in_gplates/