Related by context. Frequent words. (Click for all words.) 69 stromatolites 64 marine sediments 64 foraminifera 62 igneous rock 61 olivine 61 microfossils 60 zircons 60 continental crust 60 sedimentary rock 60 basaltic 60 hydrothermal vent 59 lavas 59 oceanic crust 59 calcareous 58 lava tubes 58 monazite 57 basalts 57 coprolites 57 theropod 57 spherules 56 solar nebula 56 basalt 56 fossils 56 lake sediments 56 sediments 56 middens 56 trilobites 55 peridotite 55 sediment cores 55 oxygen isotopes 55 Paleocene 55 mudstone 55 archaea 55 Valles Marineris 55 volcanic crater 55 gneiss 55 chert 54 stalactite 54 fossilized 54 rock outcrop 54 supercontinent 54 limestones 54 iron oxides 54 feathered dinosaurs 54 haematite 54 diatom 54 dinosaur footprints 54 isotopic composition 54 calcite 54 Radiocarbon dating 54 hadrosaur 54 igneous 54 clasts 53 otoliths 53 salt crystals 53 magmas 53 carbonaceous 53 kimberlitic 53 siliceous 53 volcanic rock 53 lunar soil 53 stalagmite 53 ejecta 53 Carboniferous 53 diatoms 53 ultramafic rocks 53 abundances 53 Meridiani 53 silicates 52 volcanic vents 52 landforms 52 Lower Cretaceous 52 Precambrian 52 sedimentary rocks 52 fossilized bones 52 hydrothermal activity 52 lichens 52 pterosaur 52 Ardipithecus 52 sauropod 52 apatite 52 Upper Cretaceous 52 Burgess Shale 52 flint tools 52 melanosomes 51 graphitic 51 jasperoid 51 glacial till 51 terrestrial ecosystems 51 Late Cretaceous 51 calcrete 51 sulphide bearing 51 CRISM 51 Columbian mammoth 51 pyroxenite 51 clades 51 alga 51 osmium 51 crustal 51 fossil 51 marine invertebrates