Related by context. Frequent words. (Click for all words.) 72 volcanism 69 Little Ice Age 63 plate tectonics 62 Pleistocene 60 glacial 58 mass extinctions 58 mass extinction 58 glaciers 57 Holocene 57 Eocene 57 permafrost 56 geologic 55 atmospheric CO2 55 volcanic activity 55 Ice Age 54 Cretaceous 54 atmospheric carbon dioxide 54 mammoths 54 glacial ice 53 sediments 53 tectonic 53 hydrothermal 53 glacier 53 lava flows 53 volcanic eruptions 52 sedimentary rock 52 landforms 52 upwelling 52 meltwater 52 sedimentary rocks 50 PETM 50 diatoms 50 El Niño 50 speciation 50 fossils 50 extinctions 49 Greenland ice 49 Earth crust 49 sedimentary 49 Triassic 49 caldera 48 hominids 48 Antarctic Peninsula 48 Antarctic Ice 48 Antarctic ice 48 prehistory 48 calcite 48 paleo 48 La Niña 48 Homo sapiens 48 fossil 48 Neanderthals 48 sunspot 47 epochs 47 dinosaurs 47 climatic 47 volcanic 47 precipitation 47 El Nino 47 cosmic microwave background 46 polar 46 dynamical 46 sunspots 46 albedo 46 Gondwana 46 ocean currents 46 climatological 46 Geophysical Research 46 magma 46 boreal 46 subduction zone 46 supernova 46 polar ice 46 latitudes 46 eukaryotes 46 geologically 46 La Nina 46 radiocarbon dating 45 anthropogenic 45 acidification 45 volcanic rocks 45 equatorial 45 wetter 45 Antarctica 45 troposphere 45 supernovae 45 geochemical 45 geological 45 cyanobacteria 45 biosphere 45 earth crust 45 Homo erectus 44 comets 44 karst 44 basalt 44 polar regions 44 oscillation 44 deformation 44 tropics 44 hunter gatherers 44 lava flow