Related by context. Frequent words. (Click for all words.) 58 polar craters 58 halite 57 dolerite 57 abyssal 56 Gusev crater 56 Bottom trawling 56 volcanic lava 55 lava tubes 55 undersea volcanoes 55 mangrove roots 54 Martian crater 54 Valles Marineris 54 gyres 54 ocean basins 54 lunar craters 54 Seafloor 53 mantled 53 volcanic craters 53 pier pilings 53 meteor impacts 53 mud volcanoes 53 snail shells 53 lateritic 52 Nares Strait 52 Sediments 52 intertidal zone 52 sargassum 52 seabeds 52 rocky reefs 52 sedimentary layers 52 gabbros 52 loess 52 permanently shadowed craters 52 middens 52 salt crystals 52 silicate minerals 52 limestone bedrock 52 copepod 51 erosional 51 basalt rock 51 asteroids comets 51 amphibolite 51 mussel shells 51 marine sediments 51 lunar soil 51 Huge chunks 51 hydrothermal vent 51 wetland vegetation 51 Lava flows 51 iron sulfate 51 jarosite 51 potsherds 51 North Pacific Gyre 51 biosignatures 51 amphipods 51 decaying vegetation 51 hummocks 51 Lake Vostok 51 icy moons 51 martian soil 51 concretions 50 phyllosilicates 50 streambanks 50 pyroxene 50 bioaccumulation 50 planktonic 50 underwater volcanoes 50 auklets 50 gaseous planets 50 hydrothermal activity 50 talus 50 Meridiani 50 greenish brown 50 ecoregions 50 freshwater habitats 50 rocky ledges 50 NASA Opportunity rover 50 intertidal 50 KT boundary 50 gastropods 50 Methylmercury 50 Mars Orbiter 50 manganese oxide 50 Calcium carbonate 50 heavily cratered 50 Martian landscape 50 microscopic pores 50 waxy substance 50 volcanic vents 49 Sand dunes 49 carbonate minerals 49 diabase 49 noble gases 49 lake sediments 49 Martian dust 49 calcareous 49 Seepage 49 rugged cliffs 49 eiders 49 sediments 49 subglacial