promotional bannermobile promotional banner

GeoTectonic

Vanilla's tangle of noodle caves is gone. In its place the underground is solid rock cut by eight hand-designed cave systems, each with its own shape, biome rules and reward for finding it.
A long, winding tunnel deep underground, carved dry, with amethyst and ores in its walls. Its name appears as you enter.

A long, winding tunnel deep underground, carved dry, with amethyst and ores in its walls. Its name appears as you enter.

The whole length of one Dry Passage, seen through the rock from below.

The whole length of one Dry Passage, seen through the rock from below.

Every setting can be changed in game, from Mod Menu on Fabric and the Config button in the mod list on Forge and NeoForge.

Every setting can be changed in game, from Mod Menu on Fabric and the Config button in the mod list on Forge and NeoForge.

The same seed and spot seen from below: with suppression off, their caverns; with suppression on (the default), the same rock left solid.

The same seed and spot seen from below: with suppression off, their caverns; with suppression on (the default), the same rock left solid.

A shaft opens into a chamber flooded to its middle and lit by glow berries. Its name appears as you enter.

A shaft opens into a chamber flooded to its middle and lit by glow berries. Its name appears as you enter.

One Cenote seen through the rock from below: the flooded chamber and the shaft rising from it.

One Cenote seen through the rock from below: the flooded chamber and the shaft rising from it.

A straight gallery at deepslate depth with iron, gold, copper and redstone in its walls and amethyst along them. Its name appears as you enter.

A straight gallery at deepslate depth with iron, gold, copper and redstone in its walls and amethyst along them. Its name appears as you enter.

The length of one Crystal Vein seen through the rock, its ores and amethyst lining the gallery.

The length of one Crystal Vein seen through the rock, its ores and amethyst lining the gallery.

A winding passage with a flowing channel, moss, hanging roots and clay. Its name appears as you enter.

A winding passage with a flowing channel, moss, hanging roots and clay. Its name appears as you enter.

Erosion Cave passages seen through the rock from below, their water channels winding through them.

Erosion Cave passages seen through the rock from below, their water channels winding through them.

A domed chamber of calcite with pointed dripstone and cave vines hanging from its roof. Its name appears as you enter.

A domed chamber of calcite with pointed dripstone and cave vines hanging from its roof. Its name appears as you enter.

A Karst Chamber seen through the rock from below: the central hub with its pool, the smaller chambers around it and the passages joining them.

A Karst Chamber seen through the rock from below: the central hub with its pool, the smaller chambers around it and the passages joining them.

A flooded passage with seagrass on its floor, running back from the coast under a low rock roof. Its name appears as you enter.

A flooded passage with seagrass on its floor, running back from the coast under a low rock roof. Its name appears as you enter.

A wider flooded chamber of a Sea Cave, its water open to the air under the rock roof.

A wider flooded chamber of a Sea Cave, its water open to the air under the rock roof.

A deep fracture walled with basalt and blackstone, studded with magma and pooled with lava. Its name appears as you enter.

A deep fracture walled with basalt and blackstone, studded with magma and pooled with lava. Its name appears as you enter.

A Tectonic Fracture seen through the rock: a long sloping rift with lava along its floor.

A Tectonic Fracture seen through the rock: a long sloping rift with lava along its floor.

A deep chamber of blackstone and basalt with a floor of magma. Its name appears as you enter.

A deep chamber of blackstone and basalt with a floor of magma. Its name appears as you enter.

Looking up the chimney that rises from a Volcanic Vent's chamber.

Looking up the chimney that rises from a Volcanic Vent's chamber.

A Volcanic Vent seen through the rock: the magma-floored chamber with its chimney rising above it.

A Volcanic Vent seen through the rock: the magma-floored chamber with its chimney rising above it.

When a newer GeoTectonic is out for your Minecraft version and loader, a chat message names it with a download link, once per game start; check_for_updates in config/geotectonic.toml turns it off.

When a newer GeoTectonic is out for your Minecraft version and loader, a chat message names it with a download link, once per game start; check_for_updates in config/geotectonic.toml turns it off.

affiliate banner image

Description

Minecraft 1.20.1 to 1.21.1: Fabric on every version, Forge on 1.20.1 to 1.21 and NeoForge from 1.20.4.


⭐ What It Does

  • The deep is solid again - vanilla cave entrances, noodle caves, cheese voids, ravines and the extra underground carvers are all suppressed, so rock is rock except where GeoTectonic cuts it.
  • Eight caves worth finding, each placed by biome and depth:
    • Tectonic Fracture - a narrow surface crack that descends toward bedrock, widening and branching. Every overworld biome.
    • Karst Chamber - biomes with a temperate or warm base temperature, never snowy land, desert, savanna or badlands. A vaulted hub with satellite rooms, stalactites, calcite veins and a floor pool you can switch off.
    • Cenote - biomes with a mild or warm base temperature, such as plains, forests and jungles, never snowy land, desert, savanna or badlands. A narrowing shaft opens into a chamber flooded to its middle, lit by glow berries.
    • Erosion Cave - a winding passage starting between Y 35 and 60 and slowly descending, with a flowing channel, moss, hanging roots and clay.
    • Sea Cave - a passage that starts just below sea level and runs 30 to 67 blocks sideways into a chamber, flooded up to two blocks below its ceiling.
    • Crystal Vein - a straight gallery at deepslate depth on a mineral fault: heavy iron, gold, copper and redstone, amethyst along its walls, a diamond alcove at one end and a sealed cave-in at the other.
    • Volcanic Vent - a hydrothermal chamber with a magma floor, basalt ceiling, rising chimney, central lava source and soul fire on the walls.
    • Dry Passage - a long, wide, winding tunnel deep underground, centered between Y -20 and 10 and carved dry, its walls showing a little amethyst and the odd ore. Every overworld biome.
  • Tune every one of them - each cave type has its own per-chunk spawn chance and an on or off switch, in a settings screen or the config file.
  • Know when you find one - an optional discovery subtitle and ambient loop each time you enter a cave, and an advancement the first time you find each type, each toggleable on its own.
  • Four commands for finding and checking - /geotectonic find, list, stats and help, at operator level 4.
  • It knows about Tectonic - bundled overrides fill Tectonic's caves, noodle caves and lava tunnels with rock and keep its underground rivers, each one switchable.
  • And about Terralith and YUNG's Better Caves - bundled overrides fill their caves with rock too, each with its own switch.

📋 Requirements

  • Minecraft 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.5, 1.20.6, 1.21 or 1.21.1 on Fabric, with Fabric API.
  • Minecraft 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.6 or 1.21 on Forge, including the NeoForge 1.20.1 fork.
  • Minecraft 1.20.4, 1.20.5, 1.20.6, 1.21 or 1.21.1 on NeoForge.
  • Mod Menu on Fabric, only to open the settings screen.

📥 Installation

  1. Install your loader, plus Fabric API if you are on Fabric.
  2. Install with the CurseForge app, or download the jar for your version and loader into your mods folder.
  3. Create a world and dig down, or run /geotectonic find fracture to be taken to the nearest one.

⚙️ Configuration

GeoTectonic writes config/geotectonic.toml on first launch:

  • [cave_generation] holds a per-chunk spawn probability and an on or off switch for each of the eight cave types, plus switches for the Karst pool, the erosion stream and the volcanic lava.
  • [aquifers] holds aquifers_enabled, on by default. Off keeps vanilla aquifers from filling caves with water and lava, including the lava lakes deep underground.
  • Vanilla springs and small lakes are not aquifers, so they stay with aquifers_enabled off. Cenotes and sea caves always hold water, so turn those two types off for dry caves.
  • [tectonic] holds one switch each for filling Tectonic's caves, noodle caves, lava tunnels and underground rivers with rock; rivers are kept unless you turn on suppress_underground_rivers.
  • [terralith] and [yungs_better_caves] each hold one switch, suppress_caves, for filling that mod's caves with rock.
  • [client] holds the three toggles for the discovery subtitle, the advancement and the ambient sound.
  • [updates] holds check_for_updates, on by default; turn it off to skip the update check.
  • The update check reads https://alkeari.com/updates/geotectonic.json once per game start and sends nothing else; only when a newer version is out for your Minecraft version and loader does it say so in chat with a link.

Change them in the settings screen, opened from Mod Menu on Fabric or the Config button in the mod list on Forge and NeoForge, or in the file. A change in the screen applies at once and a change to the file at the next game start; the [tectonic], [terralith] and [yungs_better_caves] switches take effect at the next game start. Either way a change applies only to chunks generated afterwards.

🖥️ Compatibility

  • Existing worlds. Chunks generated before you added the mod keep their vanilla caves; only new chunks get GeoTectonic's. Expect a visible seam at the edge of explored terrain.
  • Client or server. It changes world generation, so it goes on the server and on every client.
  • The Nether changes too. Its vanilla carver is suppressed the same way, so Nether terrain loses its carved tunnels.
  • Vanilla mineshafts, surface terrain, biomes, structures and ore distribution are untouched.
  • Tectonic, Terralith and YUNG's Better Caves are handled by bundled overrides that put GeoTectonic's rock back where each would carve its own caves.
  • No override is bundled for any other terrain-generation mod, so another one that carves the overworld may conflict.

🐛 Support

  • Leave a comment on this page.
  • Include your Minecraft version, your loader and its version, the mod version, and your other mods.
  • The settings, messages and cave names come in English, German, Spanish, French, Italian, Japanese, Korean, Polish, Brazilian Portuguese, Russian and Simplified Chinese; every language but English is machine translated.
  • To fix a translation or add a language, download the translation kit from this mod's Nexus Mods page, edit your language's file, and post it there.

📄 License

License terms are in the Alkeari License Agreement.

Every release, its changes and how to send feedback are on the project page at alkeari.com/projects/geotectonic.

If you want to see how it works, you can read the source code at github.com/Alkeari/GeoTectonic-PUBLIC.

💛 Donate

If you would like to donate, you can do so on Ko-fi, Patreon, PayPal, Stripe or GitHub Sponsors.

GeoTectonic Team

profile avatar
Owner
  • 1
    Followers
  • 7
    Projects
  • 41.1K
    Downloads
Donate

More from AlkeariView all

  • Ore Distribution Scanner project image

    Ore Distribution Scanner

    Stop guessing which Y level to strip-mine. Scan the terrain you have already got, then look any ore up in JEI, EMI or REI and read its real depth distribution for your world, your seed and your modpack.

    • 881
    • November 7, 2026
  • GeoGradient project image

    GeoGradient

    Biomes stop being a patchwork. GeoGradient lays climate across the world in latitude bands, so you ride from equatorial jungle through temperate forest into tundra and finally polar ice, the way a real globe is arranged.

    • 454
    • November 7, 2026
  • Genesis - World Previewer & Pregenerator project image

    Genesis - World Previewer & Pregenerator

    See the world before you make it. Genesis puts a live biome map, seed tools and world pre-generation on the Create New World screen, so you can compare seeds and pre-build the terrain before you ever spawn in.

    • 16.7K
    • November 7, 2026
  • Ultimine Unchained project image

    Ultimine Unchained

    FTB Ultimine skips blocks harder than the one you clicked, and charges a point of durability for every block it breaks. Ultimine Unchained mines the whole shape your tool can handle and caps what one operation costs you.

    • 17.4K
    • November 7, 2026
  • Ore Distribution Scanner project image

    Ore Distribution Scanner

    Stop guessing which Y level to strip-mine. Scan the terrain you have already got, then look any ore up in JEI, EMI or REI and read its real depth distribution for your world, your seed and your modpack.

    • 881
    • November 7, 2026
  • GeoGradient project image

    GeoGradient

    Biomes stop being a patchwork. GeoGradient lays climate across the world in latitude bands, so you ride from equatorial jungle through temperate forest into tundra and finally polar ice, the way a real globe is arranged.

    • 454
    • November 7, 2026
  • Genesis - World Previewer & Pregenerator project image

    Genesis - World Previewer & Pregenerator

    See the world before you make it. Genesis puts a live biome map, seed tools and world pre-generation on the Create New World screen, so you can compare seeds and pre-build the terrain before you ever spawn in.

    • 16.7K
    • November 7, 2026
  • Ultimine Unchained project image

    Ultimine Unchained

    FTB Ultimine skips blocks harder than the one you clicked, and charges a point of durability for every block it breaks. Ultimine Unchained mines the whole shape your tool can handle and caps what one operation costs you.

    • 17.4K
    • November 7, 2026