Related by context. Frequent words. (Click for all words.) 76 Eocene 75 Cretaceous 73 Miocene 71 Triassic 68 Ordovician 67 Pleistocene 67 Late Cretaceous 64 Paleozoic 63 Jurassic 62 Proterozoic 62 Mesozoic 60 Precambrian 60 Devonian 59 Holocene 54 glaciation 54 radiocarbon 53 geologically 53 paleo 53 Medieval Warm Period 53 geologic 53 volcanism 53 Little Ice Age 53 sediments 51 sedimentary rocks 50 stratigraphic 50 Archean 50 Australopithecus 50 sediment cores 50 magmatic 49 mass extinctions 49 radiocarbon dating 49 sandstones 49 abundances 49 megafauna 49 shallow depths 48 Paleolithic 48 isotopic 48 atmospheric CO2 48 Neandertals 48 Archaeopteryx 48 latitudes 48 mammoths 48 fossils 48 limestones 48 hydrothermal 48 sedimentary 48 hominids 47 geological formations 47 prehistoric 47 atmospheric carbon dioxide 47 mid latitudes 47 Neolithic 47 crustal 47 sedimentary rock 47 taxa 47 Ice Age 47 CO2 concentrations 46 stratigraphy 46 anoxic 46 lake sediments 46 lithology 46 diatoms 46 northern latitudes 46 PETM 46 fossil 46 prehistory 46 hydrothermal alteration 46 theropods 46 decadal 45 Homo erectus 45 intrusive rocks 45 unconformity 45 mineralizing 45 volcanics 45 geochemical 45 hominid 45 shales 45 atmospheric circulation 45 geologic formations 45 El Ninos 45 baleen whales 44 dinosaurs 44 anomalously 44 mass extinction 44 troposphere 44 epithermal 44 seismicity 44 geological 44 magnetic anomalies 44 caldera 44 massive sulphide mineralization 44 massive sulfide 44 subsurface 44 sauropods 44 tetrapods 44 hunter gatherers 44 atmospheric concentrations 44 Permian 44 undrilled 44 sedimentary basins 43 peridotite