Minerals, biomes

README.org

@@ -272,8 +272,12 @@ For volcanism, if we have low volcanism add 2 minerals. If we have medium volcan
 
 We then divide the number of minerals into "categories" of minerals to generate.
 Currently, we pre-filter the mineral list to only abiotic minerals.
-1 third of the total minerals, rounded down, are dedicated to the non-negotiable rock-forming minerals of the planet. These can be any rock-forming minerals from the master list that are made up of elements present in the crust. These minerals are weighted by the abundance of their constituent elements, and we randomly select the amount required using this weighting.
-Next we subtract a random number from the total mineral count, anywhere from 0 to 3. If this subtraction leaves 0 remaining minerals, skip this step. Otherwise, this selected amount becomes randomly selected native elements or gemstones that are capable of forming given the possible geo-biomes and composition.
+1 third of the total minerals, rounded down, are dedicated to the non-negotiable rock-forming minerals of the planet. These can be any rock-forming minerals from the master list that are made up of elements present in the crust. The specific modes permitted here are 5-6, 7-10, 19-21, 24-26, 31, 34, 38-43.
+These minerals are weighted by the abundance of their constituent elements, and we randomly select the amount required using this weighting. If the planet is an ice planet, one of these minerals is automatically set to ice.
+
+Next we subtract a random number from the total mineral count, anywhere from 0 to 3. If this subtraction leaves 0 remaining minerals, skip this step. Otherwise, this selected amount becomes randomly selected "rare" minerals that are capable of forming given the possible geo-biomes and composition.
+Rare minerals are minerals that are either native elements, minerals that exist in only 1 mode, have a narrow formation window (modes 29, 30, 54-57, 18), or depend on elements that are scarce in the composition (sort abundance by percent reversed to find these).
+
 And as for what minerals are capable of forming given each geo-biome, the remaining mineral count is divided by all possible geo-biomes on the planet and we determine a number of minerals that can occur per biome. These are based primarily off [[https://www.mindat.org/paragen.php][paragenetic modes]], and filtered to and weighted by the crust composition elements. 
 
 **** Impact
@@ -306,6 +310,113 @@ Mode 34 and 27 can generate in Pegmatitic biomes.
 **** Magmatic
 Modes 7-9, 19-20, 27, 35-38 can generate in Magmatic biomes.
 
+*** Surface Biomes
+Each chunk has a surface biome randomly chosen from a set derived from the geo-biome. Surface biomes are different for terrestrial, metallic, and ice worlds as opposed to water worlds.
+
+These biomes also determine the sorts of surface features that can generate within the chunk. For water worlds, these are submarine.
+
+**** Terrestrial, Metallic, Ice
+***** Primordial
+****** Ancient Highlands
+The planet's original, battered crust. Heavy cratering, rugged landscape.
+****** Impact Basin
+A single vast circular depression from a massive impact, with concentric rings and a flat floor.
+***** Magmatic
+****** Shield Volcano
+A broad, gently sloping mountain.
+****** Stratovolcano
+A classic volcano built from alternating layers of lava and ash.
+****** Volcanic Plateau
+An elevated plain formed by thick layers of lava that flooded from fissures, creating flat top mountains.
+****** Lava Plain
+A flat terrain covered by young lava flows.
+***** Pegmatitic
+****** Pegmatite DIke Swarm
+A network of mineral veins cutting through old rock, marked by large protruding crystals.
+****** Granitic Core Complex
+The exposed, deep interior of a solidifed magma chamber, showing large crystals.
+***** Fumarolic
+****** Fumarole Field
+A rugged area pockmarked by gas vents and brightly coloured mineral crusts.
+****** Solfatara
+A type of fumarole field creating extensive sulfar deposits.
+***** Hydrothermal
+Temperature is irrelevant for surface biome generation.
+****** Geyser Basin
+A volatile area of hot springs, geysers, and mineral terraces.
+****** Epithermal Vein Field
+A rocky landscape crisscrossed by prominent mineral veins.
+***** Sedimentary
+****** Alluvial Fan
+A fan-shaped deposit of sediment where a steep stream slows upon entering a flat plain.
+****** Fluvial Channel
+The active or fossilized path of a river system.
+****** Lacustrine Basin
+A dry or wet lakebed with fine layered sediments.
+****** Aeolian Dune Field
+A desert of sand and other grains sculpted by wind into rolling dunes.
+***** Metamorphic
+****** Collisional Mountain Belt
+A linear range of high, folded, and faulted mountains.
+****** Metamorphic Dome
+A large, rounded uplift.
+***** Supergene
+****** Gossan Cap
+A hilltop marking the weathered top of a large ore deposit.
+****** Lateritic Plateau
+A tableland capped by a thick, hard layer of iron or aluminium oxides.
+***** Impact
+****** Complex Crater
+A large crater with a central peak or peak ring.
+****** Rayed Crater
+A relatively fresh impact crater with bright, linear streaks of ejecta.
+****** Palimpsest
+A fait, ghost-like circular scar where an ancient crater's topography has been erased over time.
+**** Water Worlds
+***** Primordial
+****** Abyssal Plain
+Deep, dark sediment-covered ocean floor.
+****** Seamount Province
+Isolated, often conical underwater mountains. Remnants of ancient volcanic activity.
+***** Magmatic
+****** Submarine Volcano
+An active volcano built on the ocean floor.
+****** Oceanic Plateau
+A vast, elevated region of the seafloor formed by massive outpourings of lava.
+****** Pillow Lava Field
+Expansive areas of the seafloor covered in characteristic bulbous pillow lava formations.
+***** Pegmatitic
+****** Subaqueous Pegmatite Still
+A rare layer of crystals formed beneath the seabad, exposed by erosion.
+***** Fumarolic
+****** Submarine Fumarole Field
+Gas vents on the seafloor.
+****** Shallow Water Gas Vent Plume Zone
+Areas where bouyant gas plumes rise through the water column, creating columns of bubbles and mineral sediment.
+***** Hydrothermal
+****** Deep-sea Vent Field
+Cluster of black smoker or white smoke chimneys on the seafloor.
+****** Hydrothermal Mound Complex
+Large, layered deposits of minerals built up from long-lived venting.
+****** Shallow Hydrothermal System
+Venting mineral precipitation and unique chemistry in shelf-sea environments.
+***** Sedimentary
+****** Submarine Fan
+A large, fan-shaped accumulation of sediment.
+****** Pelagic Sediment Plain
+Vast, flat areas of the deep ocean covered by slow, continuous rain of fine clay.
+***** Metamorphic
+****** Subduction Complex
+A region of intensely deformed, mixed, and metamorphosed rocks on the seafloor.
+****** Oceanic Core Complex
+A dome-like exposure of deep mantle and crustal rocks.
+***** Supergene
+****** Seafloor Weathering Crust
+A layer of enriched rock at shallow depths.
+***** Impact
+****** Submarine Impact Crater
+A circular impact structure on the ocean floor.
+
 ** Limitations
 - Elemental abundances are fully random beyond the top 10.
 - Non-unary system generation is not implemented because I don't want to write the orbit math for it.