Related by context. Frequent words. (Click for all words.) 72 Carboniferous 72 Ordovician 68 Paleozoic 68 Precambrian 68 lavas 67 Cretaceous 67 Quaternary 66 Eocene 66 basalts 66 Late Cretaceous 65 Proterozoic 65 Mesozoic 65 Paleocene 65 marine sediments 63 Pliocene 63 sedimentary rocks 62 volcanism 62 igneous 62 Triassic 62 glaciation 62 magmatic 62 basaltic 62 Pleistocene 60 Oligocene 60 supercontinent 60 crustal 59 zircons 59 continental crust 59 carbonaceous 59 Miocene 59 interglacial 59 Cretaceous Period 59 apatite 59 Lower Cretaceous 59 biogenic 58 tuffs 58 solar nebula 58 abundances 58 graben 58 lithosphere 58 banded iron 58 siliceous 58 Burgess Shale 58 facies 58 sedimentary 58 lake sediments 58 isotopic 58 sedimentary rock 57 Archean 57 sediments 57 Younger Dryas 57 limestones 57 terrestrial ecosystems 57 microfossils 57 volcanic rocks 56 stromatolites 56 olivine 56 ocean ridges 56 intrusives 56 intrusive rocks 56 Cambrian explosion 56 oceanic crust 56 hydrothermal 56 trilobites 56 atmospheric methane 56 Holocene 56 ultramafic rocks 56 Silurian 56 interglacial period 55 calcareous 55 carbonatite 55 volcanics 55 oxygen isotopes 55 peridotite 54 Geochemistry 54 felsic 54 metasedimentary rocks 54 calcite 54 gabbro 54 caldera 54 granitic 54 mafic volcanics 54 mid latitudes 54 geologic 54 mafic 54 gneiss 54 graphitic 54 Devonian 53 Uranium mineralization 53 carbonate rocks 53 silicates 53 foraminifera 53 iron oxides 53 andesite 53 megafauna 53 anomalously 53 mineralogy 53 sulphide bearing 53 taxa 53 bornite 53 morphologies