Related by context. Frequent words. (Click for all words.) 67 stromatolites 60 foraminifera 57 igneous rocks 57 marine sediments 56 trilobites 55 basaltic 55 lava tubes 55 igneous rock 55 hydrothermal vent 54 olivine 54 Cyanobacteria 54 microfossils 54 snail shells 54 mud volcanoes 54 spherules 53 marine invertebrates 53 phyla 53 basalts 53 oceanic crust 53 calcite 53 microscopic organisms 52 morphologically 52 landforms 52 isotope ratios 52 osmium 52 ammonites 51 biogeochemical 51 morphologies 51 prokaryotes 51 taxa 51 zircons 51 underwater volcanoes 51 pyroclastic 51 middens 50 Fig. 1A 50 limestone caves 50 clades 50 iron oxides 50 globular clusters 50 planktonic 50 Precambrian 50 igneous 50 lichens 50 peridotite 49 single celled organisms 49 terrestrial ecosystems 49 Burgess Shale 49 elemental composition 49 relict 49 planetary nebula 49 sedimentary rock 49 filamentous 49 magmas 48 diatoms 48 isotopic composition 48 basalt 48 ejecta 48 planetary nebulae 48 particle detectors 48 hydrothermal activity 48 Lichens 48 Radiocarbon dating 48 lunar soil 48 rock outcrops 48 horned dinosaur 48 magnetars 48 carnivorous dinosaur 48 sediments 47 faunal 47 toothed whales 47 feathered dinosaurs 47 organic molecules 47 lavas 47 seamounts 47 amphorae 47 intertidal 47 single celled 47 mycelium 47 oxygen isotopes 47 volcanic vents 47 regolith 47 dinoflagellates 47 sea anemones 47 continental crust 47 landform 47 biomes 47 Meridiani 47 bacterial colonies 47 subduction zones 47 cordgrass 47 organisms 47 planetesimals 47 supernova remnants 46 aquatic invertebrates 46 moonlets 46 garnets 46 salt crystals 46 Meteorites 46 silicates 46 Microorganisms 46 Nematodes