Related by context. Frequent words. (Click for all words.) 63 Ordovician 62 Carboniferous 61 Pliocene 60 Quaternary 60 interglacial 60 Late Cretaceous 59 Paleozoic 59 Younger Dryas 57 Eocene 57 interglacial period 57 Snowball Earth 57 Paleocene 57 Proterozoic 57 Pleistocene 56 planktonic 56 glaciation 56 foraminifera 56 biogeochemical 56 Cretaceous 56 hydrothermal activity 56 Mesozoic 56 Precambrian 56 isotopic composition 56 anoxia 55 Cretaceous Period 55 marine sediments 55 Jurassic Period 55 Oligocene 54 terrestrial ecosystems 54 Triassic 54 anomalously 54 Silurian 54 depositional 54 Cambrian explosion 54 Holocene 54 magmas 53 morphologies 53 igneous rocks 53 lavas 53 volcanism 53 diatoms 53 anoxic 53 diatom 53 Miocene 53 lithosphere 53 continental crust 53 paleoclimate 53 abundances 53 atmospheric methane 52 magmatic 52 marine invertebrates 52 tuffs 52 trilobites 52 atmospheric CO 52 crustal 52 solar nebula 52 tetrapod 52 solar irradiance 52 carbonaceous 51 basalts 51 surficial 51 lake sediments 51 granitic 51 methanogens 51 decadal 51 hydrological cycle 51 otoliths 51 basaltic 51 fossilization 51 Lower Cretaceous 51 solar corona 51 stromatolites 51 zircons 50 facies 50 poleward 50 SSTs 50 hydrothermal vent 50 sediments 50 El Niños 50 isotopic 50 Upper Cretaceous 50 elemental composition 50 peridotite 50 sediment cores 50 Polar Regions 50 angiosperms 50 Geochemistry 50 Pacific Decadal Oscillation 50 microfossils 50 desorption 49 pyroxenite 49 maxima 49 calcareous 49 Devonian 49 Palaeolithic 49 igneous 49 Little Ice Age 49 oxygen isotopes 49 Fig. 1A 49 Medieval Warm Period 49 lava tubes