Related by context. Frequent words. (Click for all words.) 63 radiocarbon dating 61 radiocarbon 57 igneous rocks 56 microfossils 56 isotopic 56 stromatolites 55 zircons 55 Radiocarbon dating 55 elemental composition 55 isotopic composition 54 lake sediments 54 oxygen isotopes 53 marine sediments 53 paleoclimate 53 fossilization 53 astronomical observations 53 biogeochemical 53 igneous rock 52 coprolites 52 numerical simulations 52 Quaternary 52 Snowball Earth 52 geologic 52 glaciation 52 Carboniferous 52 lunar soil 51 Precambrian 51 radioactive decay 51 foraminifera 51 geological 50 abundances 50 plate tectonics 50 geochemical 50 Computer simulations 50 fossils 50 Geochemistry 50 numerical modeling 50 solar nebula 50 lavas 50 Jurassic Period 50 geomorphology 50 glaciations 49 Egyptian pyramids 49 theoretical calculations 49 Burgess Shale 49 mineralogy 49 computer simulations 49 sediment cores 49 lithosphere 49 depositional 49 gravitational lensing 49 trilobites 49 Archaeopteryx 49 lava tubes 49 Lake Vostok 49 basalts 49 magmas 48 Martian rocks 48 astrobiologists 48 theropods 48 Pliocene 48 feathered dinosaurs 48 Late Cretaceous 48 spherules 48 Voyager spacecraft 48 volcanism 48 galaxy formation 48 infrared spectroscopy 48 continental drift 48 osmium 48 radial velocity 48 systematics 48 microlensing 48 geological geophysical 48 igneous 48 fossil 48 oceanic crust 48 Palaeolithic 47 Meridiani 47 sedimentary rock 47 abiotic 47 Cerling 47 palaeontology 47 nanosized 47 zeolites 47 spectral signatures 47 supercontinent 47 Neandertal 47 geologists 47 nanomechanical 47 continental crust 47 regolith 47 hominins 46 iron fertilization 46 geology 46 Lunar Prospector 46 calcite 46 Harappan 46 cosmologists 46 Chicxulub 46 palaeontologists