Related by context. Frequent words. (Click for all words.) 77 geologic formations 63 rock formations 63 geologically 59 shales 58 shale formations 58 sedimentary basins 57 sedimentary rock 56 geologic 55 geological 54 coal seams 54 gas hydrates 53 basins 52 subsurface 52 sediments 52 shale deposits 52 geology 52 permafrost 52 underground caverns 51 shale 51 sedimentary rocks 51 Geologically 51 hydrocarbons 51 sedimentary basin 51 sandstones 51 fossils 51 caverns 51 landforms 50 basalts 50 aquifers 49 regolith 49 dinosaur fossils 49 Ordovician 49 salt caverns 49 undrilled 49 liquid hydrocarbons 49 rock outcrops 48 Eocene 48 peridotite 48 soils 48 seamounts 48 paleontological 48 iron oxides 48 biodiversity hotspots 48 stratigraphy 47 Pliocene 47 reservoirs 47 cavern 47 hydrocarbon 47 Miocene 47 karst 47 hydrothermal vents 47 biota 47 astronomical objects 47 hydrothermal 47 Bakken Formation 47 sandstone 47 formations 47 VMS deposits 47 sedimentary 47 archeological sites 46 Late Cretaceous 46 basalt 46 carbonates 46 Bakken formation 46 stratigraphic 46 Precambrian 46 limestones 46 lake sediments 46 Paleozoic 46 orebodies 46 Geochemistry 46 shale gas 46 hydrocarbon reserves 46 Basins 46 outcrops 46 moon Europa 46 sediment cores 46 alluvium 45 Oligocene 45 wells drilled 45 magmatic 45 methane 45 crustal 45 Utica Shale 45 Cretaceous 45 discoveries 45 peat bogs 45 mineral occurrences 45 economically recoverable 45 geochemistry 45 radiometric anomalies 45 gas condensate 45 tcf 45 shallow depths 45 relatively unexplored 45 lithium brine 44 hydrocarbon bearing 44 volcanism 44 olivine 44 Bakken shale 44 dimensional seismic