Related by context. Frequent words. (Click for all words.) 52 sludges 50 calcareous 49 iron oxides 48 gravels 48 Sediments 47 sand 47 siltstones 47 sands 46 borate 46 salts 46 sedimentary rock 46 glacial till 45 mud 45 sediments 45 tuffs 45 sandstone reservoirs 45 limestones 44 clays 44 salt domes 44 marl 44 calcium carbonate 44 mineral salts 44 alkali 44 sphagnum moss 44 calcite 44 steam vents 44 alluvium 44 limestone formations 44 calcrete 43 mudstone 43 barite 43 silica sand 43 igneous rock 43 silicates 43 carbonaceous 43 methane hydrate 43 salt crystals 43 alluvial deposits 42 sandstones 42 carbonate 42 pyritic 42 cenotes 42 pebbly 42 silica 42 pumice 42 peridotite 42 interbedded 42 seabeds 42 granites 42 surficial 41 spodumene 41 oxidised 41 geological formations 41 sulfides 41 rock formations 41 silty 41 iron oxide 41 granules 41 massive sulphide deposits 41 hydroxide 41 brines 41 gelatinous 41 slimes 41 schists 41 copper oxide 41 hydroxyapatite 41 methane hydrates 41 frac sand 41 chalcocite 40 lava tubes 40 subsurface 40 evaporation ponds 40 sulphate 40 intertidal 40 sulphates 40 rocky outcrops 40 zeolites 40 oily residue 40 oxygenating 40 goo 40 lavas 40 sediment 40 basaltic 40 hot springs 40 haematite 40 geologic formation 40 hydrocarbon molecules 40 geologic formations 40 colloidal 40 basalts 40 basalt 40 anticline 40 sandy loam 40 porphyries 40 chlorite 39 limestone caves 39 colloid 39 regolith 39 sedimentary rocks 39 coarse sand 39 siliceous