Related by context. Frequent words. (Click for all words.) 54 sedimentary rock 54 marine sediments 53 continental crust 53 gas hydrates 52 kerogen 51 stromatolites 51 permafrost 51 interglacial period 50 volcanism 50 olivine 50 Late Cretaceous 50 methane hydrates 50 magmatic 49 sedimentary basins 49 peridotite 49 methane hydrate 49 glacial ice 48 supercontinent 48 Lower Cretaceous 48 Bakken formation 47 interglacial 47 Meridiani 47 Cretaceous Period 47 diatoms 47 atmospheric methane 47 solar nebula 46 Carboniferous 46 geologic formations 46 geological formations 46 hydrological cycle 46 Precambrian 46 lavas 46 glaciation 46 oceanic crust 46 sedimentary basin 46 geologic formation 46 Paleocene 45 earth crust 45 diatom 45 Volcanic eruptions 45 Antarctic Ice 45 Younger Dryas 45 terrestrial ecosystems 45 western Siberia 45 mid latitudes 44 subduction zones 44 aerosol particles 44 H. erectus 44 mountain pine beetles 44 ocean ridges 44 Tarim Basin 44 Quaternary 44 Bakken Formation 44 lithosphere 44 geologically 44 Permafrost 44 magma chamber 44 technically recoverable 44 spherules 44 hydrothermal 43 Mark Serreze 43 melting permafrost 43 preindustrial 43 lunar soil 43 megafauna 43 glaciers melting 43 glacial melting 43 northern latitudes 43 crustal 43 mudstone 43 geologically active 43 alluvial deposits 43 basalts 43 atmospheric CO 43 equatorial Pacific Ocean 43 tundra 43 melanosomes 43 single celled organisms 43 Oetzi 43 temperate zones 43 Ordovician 43 Tibetan Plateau 43 retreating glaciers 43 Cretaceous 42 Cascadia Subduction Zone 42 Pliocene 42 subduction zone 42 Poinar 42 methane 42 Weddell Sea 42 Greenland glaciers 42 iron oxides 42 seafloor 42 Neandertal 42 Earth crust 42 coprolites 42 pikas 42 meltwater 42 hominins 42 Ellesmere Island 42 economically recoverable