Related by context. Frequent words. (Click for all words.) 53 Lava flows 52 icy crust 51 basaltic 49 tuffs 49 heavily cratered 49 warmer wetter 48 spherules 48 Gusev crater 48 Valles Marineris 47 igneous rock 47 clasts 47 hydrothermal fluids 47 gneisses 47 lithosphere 46 mid latitudes 46 Martian equator 46 pyroclastic 46 polar vortex 46 andesitic 46 martian soil 46 volcanically active 46 continental crust 46 lava tubes 46 oceanic crust 45 mudstone 45 lunar soil 45 undersea volcanoes 45 polar 45 Russia Kamchatka Peninsula 45 extinct volcanoes 45 Svalbard archipelago 45 igneous rocks 45 calcareous 45 tropopause 45 sulphates 45 aragonite 45 exosphere 45 sparse vegetation 44 equatorial regions 44 stratiform 44 hydrothermally altered 44 refugia 44 polar caps 44 polar craters 44 Oort cloud 44 escarpments 44 Scientists theorize 44 granitic rocks 44 Migrating birds 44 Neoproterozoic 44 streambanks 44 steam vents 44 magmas 44 Earthlike 44 jarosite 43 icy moons 43 equatorial 43 hydrothermal activity 43 amphipods 43 scarps 43 Arctic tundra 43 schists 43 igneous 43 Meridiani Planum 43 equatorial waters 43 rock outcrop 43 Cabeus 43 Lake Vostok 43 meteor impacts 43 clathrates 43 Weddell Sea 43 gaseous planets 43 glaciated 43 hardened lava 43 volcanic vents 43 moonlets 43 subglacial 43 sandstone formations 43 carbonate minerals 43 sedimentary rock 43 Kuiper belt 42 marine sediments 42 Saturn moon Enceladus 42 mud volcanoes 42 Gondwanaland 42 silty 42 crater 42 Oort Cloud 42 Meridiani 42 moon Enceladus 42 talus 42 lava flowing 42 Mini SAR 42 lava flows 42 molten rock 42 lunar craters 42 volcanic rock 42 hydrothermal vent 42 pyroclastic flow 42 metamorphic rocks 42 fatty tissues