Index

Page numbers in italic refer to Figures. Page numbers in bold refer to Tables.

Abalos Colles 257, 258, 259 channel networks 5–6 cratered cones 259, 271, 275 formation 9 layered cones 258, 259, 260, 261, Lethe Vallis 206–226 268–271, 273–275 anastomosing patterns 220 erosion 261, 268 outflow 11–12, 12 Abalos Mensa 258, 267 Sulci Gordii 231, 232–255 ablation, solar, Chasma Boreale 277 chaos regions 12 adsorption 146 interior layered deposits 281, 282, 284, 285, Adventdalen, Spitzbergen 113, 114 286, 289–290, 292, 294 periglacial landforms 118 comparison with Valles Marineris 295–296 comparison with Mars 115–118 Chasma Boreale 257, 258, 259, 267 ice-wedge polygons 121 elevation 262–263, 264, 269 aeolian processes 10, 13, 15 formation 276–277 air-fall accumulation, Chasma Boreale 277 air-fall accumulation 277 alases 133, 143 wind erosion 277 Alba Patera Formation 50 outflow event 275, 277 albedo 5, 6 Chryse Planitia, sublimation landforms, ejecta alcove-channel-apron gully morphology 151, 152, 153 blankets 141 alluvial flow clastic forms gully formation 174 blockfields 92, 93, 95, 98, 107 slope–area analysis 185 circles 92, 94, 103 Earth study sites 183, 184, 186, 189 garlands 92, 103 Amazonian epoch 9 islands 90–91, 92, 108 Amazonis Planitia 5 lobate 93–94, 98, 103, 105 thaw 88 Spitzbergen 116, 117 Aorounga Impact Crater, Chad 33 Thaumasia 76, 77–78, 79, 80, 81,82 Arabia Terra 5 nets 91, 92 Aram Chaos, interior layered deposits 282, 285, 286 protalus lobes and ramparts, Arcadia Formation 50 Spitzbergen 117 Ares Vallis stripes 92, 93–94, 95–98, 103, 105, 107 alases 143 Spitzbergen 116 outflow channel 12 clay minerals, sublimation 145–146 Argyre Planitia 7,70 climate 6, 10 Arsinoes Chaos, interior layered deposit 282, 287, 288, Context Camera instrument (CTX) 7 292, 297 interior layered deposits (ILDs) 283 Athabasca Vallis 9, 12, 203, 204 Lethe Vallis 205 ground-ice thaw processes 88, 100 mid-latitude landscape evolution 112 atmosphere 6, 10–11 Rupes Tenuis unit 262, 263 Aureum Chaos, interior layered deposits 282, 284, 285, Sulci Gordii 230, 232 286, 288, 289 Tempe Terra periglacial landforms 45, 46 Aurorae Chaos, interior layered deposits 282, 287, 288, Thaumasia Highlands 71, 73, 74 292, 294, 296 Copernicus Crater, Moon 29 Aurorae Sinus 5 core 9–10 cracks bajadas 117 effect on sublimation 146 bedrock, and gullies 154, 155–156 thermal contraction 139, 142, 143 bergschrund see randkluft crater counting, Sulci Gordii 248–251 blockfields 92, 93, 95, 107 crater fill brine, in gully formation 152, 173–174 concentric 43 Brøgger Peninsula, Spitzbergen 113, 114, 117 mid-latitude 136 lineated, Thaumasia Highlands 73–76, 78 ‘canals’ 5, 6 craters see impact craters canyons see channel networks, outflow creep 61, 195–196 Capri Chasma, interior layered deposits 287, 295, see also frost creep; soil creep 296, 298 CRISM (Compact Reconnaissance Imaging Spectrometer) carbon dioxide, ice caps 10, 134 7,70 Cavi Angusti 133, 134 interior layered deposits 283, 289, 291 Cerberus Fossae 203, 204 cross bedding 15 periglacial landforms 142 crust 10 302 INDEX cryoturbation, regolith 87–88, 103, 108 equifinality 1, 111 cumulative area distribution (CAD) 175, 178, 183, 186, Erebus Crater 14,15 189, 190, 193, 194 Eros, grooves 31, 38–39, 40 erosion Dao Vallis, gully morphology 153 aeolian, Thaumasia Highlands 80 Death Valley, California, slope–area analysis 177, 179, Chasma Boreale formation 277 181, 184, 186, 191 interior layered deposits 293 debris aprons Lethe Vallis channels 220, 221 lobate 12 Rupes Tenuis scarp 259, 261 mid-latitude 136–137, 140 Rupes Tenuis unit 265, 273–278 Tempe Terra region 43–44, 46–47, 50 Tempe Terra–Mareotis Fossae region 60–61, 63 age constraints 59–61 Escorial Crater mesa 257, 258, 259, 271, 272, 273 erosion 60–61 elevation 269–271 insolation control 57–58 evaporation, interior layered deposit (ILD) formation landforms 54–58 196–197 landscape evolution 51,61–62 exploration 5–6 morphometry 58–59 Thaumasia Highlands 76, 78, 80, 82 fans debris flow 121 ground-ice thaw processes 97–98 gully formation 173–174 Svalbard and Mars 115, 117, 121 slope–area analysis 185 faults 122 Earth study sites 181, 182, 183, 184, 186, 187 Thaumasia Highlands 81 Mars 193–194, 196 fill and spill sequence, Lethe Vallis channel Spitzbergen 115, 117–118 network 221–224, 225 Deimos, lack of grooves 38 firn 123 depressions flooding 12–13 scalloped 121, 134 Lethe Vallis 220 Utopia Planitia 137–139 landforms 213–217 sublimation landforms, equatorial regions 142–143 formation, Mars 9 Deuteronilus Mensae 115 fracture hypothesis, Phobos’ grooves 22, 30–34, 36 sublimation landforms 140 fractures Deuteronilus–Protonilus–Nilosyrtis Mensae suite 46, 49, contour-parallel 124, 125 51, 61 and sublimation 146 dichotomy boundary, Tempe Terra, landforms 43–63 freeze–thaw cycles 88, 89, 93, 103, 125, 139, 142 digital elevation models 71, 113, 174, 176, 178, 196 fretted terrain 48, 49, 73 drag forces, Phobos see also valleys, fretted as origin of grooves 22, 35–36 Front Range, Colorado, slope–area analysis 177, 179, reopening fractures 36 181–182, 184, 186, 191 dunes 10, 11, 14,15 frost creep 93, 105, 120, 125, 195, 196 dust 119 see also glaciers, dust; mantling, dusty Galap Crater, gullies 172 dust devils 11, 15 Ganges Chasma, interior layered deposits 282, 283, 284, dust storms 10–11 287, 290, 292, 293, 294–298 Gasa Crater, gullies, slope–area analysis 180, 182–183, early missions 5 185, 187, 188, 190, 192, 194 ejecta, secondary impact craters, Phobos 38 Gaspra, grooves 31,38 ejecta blankets 141, 143 gelifluction 44, 61, 94, 95, 96, 105, 107 ‘El Capitan’, vugs 15 geology, timescale 9 Elysium Mons 6, 7, 203, 204 glaciers Elysium Planitia 9, 203–226 dust ground-ice processes 88 cold-based 119, 120, 121 linked basins 205–206 polythermal 120, 122 periglacial landforms 142 rock 43–44, 61, 69–70 platy-ridged-polygonized terrain 203–204, 205, 206, Spitzbergen 117 215 Thaumasia Highlands 80 see also Western Elysium Basin Gorgonum Basin, gullies 153 Elysium Volcanic Rise 204, 205 grabens 122 Eminescu Crater, Mercury 29 Sulci Gordii region 247, 248, 251 Endeavour Crater 15 grain size, effect on sublimation 145 Eos Chasma, interior layered deposits 287, 295, 296, 298 granular flow, gully formation 173–174 epochs 9 Great Kobuk Sand Dunes, niveo-aeolian features 122, 123 equatorial regions grooves ground-ice, distribution 147–148 Eros 31 sublimation landforms 141–144 Phobos 21–40 INDEX 303 ground-ice Hesperia Planum, formation 9 stability Hesperian epoch 9 distribution model 146–147 high latitudes obliquity 112, 118, 121 ground-ice, distribution 147 sublimation 145–146 ground-ice thaw 87–108 thaw sublimation landforms, subsurface ice 134 and formation of gullies 153 HiRISE images 1, 7, 12, 63, 71 high latitude 87–108 ground-ice processes 88–89 clastic forms 90–103 gullies 154, 155, 172, 178, 181, 196 Mars Phoenix lander, survey 88–89 interior layered deposits (ILDs) 283 groundwater 122–123 Lethe Vallis 205 and formation of gullies 12, 153 mid-latitudes landscape evolution 112 and interior layered deposits (ILDs) 281, 296 Rupes Tenuis Unit 260, 262, 263 gullies 12, 13, 151–168, 171–197 sublimation landforms 135, 136, 138, 144, 147 alcove-channel-apron morphology 151, 152, 153 HRSC images 7, 12 classification 153–156, 158, 160 interior layered deposits (ILDs) 283 ‘reactivated’ 156, 157, 159, 166 Lethe Vallis 205 evolution 161–162 mid-latitude landscape evolution 113 ‘recent’ 162–164, 166 Phobos grooves 22–26 Type A 154–155, 157, 158 Rupes Tenuis unit 262, 263 evolution 160–161 sublimation landforms 140 Type B 154, 155–156, 157, 158 Tempe Terra periglacial landforms 44–45 distribution 151, 167–168 Thaumasia Highlands 71, 72 crater central peaks 151, 158, 164, 167–168 humidity, effect on sublimation 145 crater walls 151, 158, 164, 167 hydrological cycle, Mars Phoenix lander site 87 hills 151, 158, 164, 167 hydrothermal activity 15 valleys 151, 158, 164, 167 Sulci Gordii channel systems 254 evolution 160 Hyperborea Lingula 257, 258, 259 fluvioperiglacial 88, 96–103, 104, 105, 107 elevation 269, 275 braiding 103, 104, 107, 117 Hyperboreae Undae 258, 259 formation processes 152–153, 171–175 Hyperboreus Labyrinthus 258, 259 alluvial flow 174, 183, 185 aquifer outflow model 171, 173 Iani Chaos, interior layered deposits 12, 282, 285, 286, atmospheric theories 153 288, 289–290, 294 debris flow 173–174, 181–183, 193–194, 196 ice dry granular flow 173–174 carbon dioxide 10, 134 effect of obliquity 152–153, 163–164 water 10 fluids involved 173–174, 196–197 sublimation 133–148 slope–area analysis 174–198 see also ground-ice see also slope–area analysis ice lenses 139 subsurface theories 153 Ida, grooves 31,38 surface or near-surface melting 173, 196–197 impact craters 5 latitude distribution 151, 157, 158 central peaks, gullies 151, 158 ‘reactivated gullies’ 161–162, 165, 166 mid-latitudes 141 Type A 160–161, 163, 167 pedestal length 159–160, 167 ejecta blankets 141, 143 light-toned deposits 171 erosion, Rupes Tenuis unit 276 morphology 151, 152, 153, 171, 172 pits 133, 134 orientation 151, 157–158, 159, 162, 163, 166 Rupes Tenuis unit, erosion 275–276 remnant-massif/debris-apron constructs (RACs) secondary chains 53–54, 55–56, 62 Eros 31 Svalbard and Mars 115, 116, 124 Mercury 29,38 water sources 196–197 Moon 29,38 Gusev Crater landing site 14, 60 Phobos 21–22, 29,36–39 walls, gullies 151, 158, 172 Hale crater 116, 117, 121, 124 see also crater fills hanging valleys, Lethe Vallis 211, 213, 215, 220 in situ observations 1, 13–15 Harmakhis Vallis, gully morphology 153 insolation, debris-apron formation 57–58 head scarps, Lethe Vallis 214 interior layered deposits (ILDs) 281–298 Hellas impact basin 6, 7 chaotic terrain 281, 282, 284, 285, 286, 289–290, hematite 1–2, 15 292, 294 interior layered deposit (ILD) surfaces 281, 285, 286, comparison 295–296 290, 293, 295, 296, 297 erosion 297–298 hemispheres, dichotomy 5, 6, 7 mineralogy 283, 296–297 304 INDEX interior layered deposits (ILDs) (Continued) thalweg long profile 209, 212–213 potential formation and evolution 293, 296–298 volcanic v. fluvial models 224–225 rock decomposition 296, 297 levees, debris flow 173, 253 thermal inertia 283 light toned deposits 171 Valles Marineris 281, 287, 294–295 Limtoe Crater, Phobos 30 water sources 296–297 liquifaction, regolith 102, 103, 105, 107, 108 internal structure 9–10 lobes Isidis Planitia 7 clastic 93–94, 98, 99, 104 islands ground-ice thaw processes, Svalbard and Ares Vallis outflow channel 12 Mars 115, 116 ground-ice thaw processes 90–91, 92, 108 Lomonsov Crater, clasts 92–93, 94 Lethe Vallis channel network 209, 210, 211, 212–213, 213, 221 Mangala Valles 12 Sulci Gordii channel systems 241 mantle, latitude-dependent 120, 136, 137 mantling Kaiser Crater, gullies 172 dusty 13, 119, 121 slope–area analysis 180, 181, 183, 185, 187, 188, 190, and gully formation 153, 154–156 192, 194–195 plateau, Thaumasia Highlands 72–73, 78, 80 karst, sublimation 103 ‘reactivated’ gullies 156 kieserite, interior layered deposits 285, 286–287, 290, remnant-massif/debris-apron constructs 291, 293, 295 (RACs) 51, 54, 55, 56–57, 61–62 knobs, sublimation landforms 135, 138 Mare Erythreum 5 Mare Sirenum 5 lag deposit 121, 125 Mareotis Fossae landers 13–14 geological setting 47–51 landforms, periglacial stratigraphy 50–51 latitude dependency 111, 120, 126, 137 Mariner missions 5 models 118–125 Mars 3 probe 5 dry scenario 119–121 Mars, formation 9 snow scenario 120, 123, 125 Mars Explorer Rover wet scenario 120, 122–123 Opportunity 1–2, 13, 14,15 Svalbard 111–126 Spirit 13,14–15 morphological comparison with Mars 114–118 Mars Express 7 Thaumasia Highlands 69–83 Mars Global Surveyor 7, 259 landscape evolution, mid-latitudes 111–126 Mars Odyssey 7 landslides 187 Mars Orbiter Camera (MOC) images 7,69 RACs 54, 55,61 gullies 13, 171 lava interior layered deposits (ILDs) 283, 284 flood, Lethe Vallis 224–225 Rupes Tenuis unit 262, 263 Sulci Gordii area 233 sublimation landforms 134–135, 137, 139 fluid flow 241–243, 246–247, 252–253 Sulci Gordii region 230, 232 layering Mars Orbiter Laser Altimeter (MOLA) 7 Rupes Tenuis unit 259–278 gullies 195 see also interior layered deposits interior layered deposits (ILDs) 284 Lethe Vallis channel network 203, 206–226 Lethe Vallis 205, 208 anastomosing patterns 220 lobate debris aprons 44, 45 basin-channel fill and spill evolution 221–224, 225 Rupes Tenuis unit 259, 262, 264 cataract 1 208, 209, 212, 213 Sulci Gordii region 230, 232 cataract 2 208, 209, 213 Thaumasia Highlands 71 cataract 3 208, 210, 213, 214 Mars Pathfinder 13 cataract 4 208, 209, 211, 213, 214 Mars Phoenix lander 13–14 channel cross-sections 211, 218 ground-ice processes 88, 112, 147 crescentic landforms 215, 216, 217, 218 reconnaissance survey 88–89 discharge 217–220 hydrological cycle 87 erosional power 220, 221 Mars Reconnaissance Orbiter 1, 7,71 flooding 220–221 Mars Sojourner Rover 13 formative time 220 Marsnik 1 5 hanging valleys 211, 213, 215, 220 Marte Vallis channel, periglacial landforms 142 islands 209, 210, 211, 212–213, 213, 221 Martian Cratered Cones 259, 271, 275 landforms 213–217 mass wasting lineations 215, 216–217 gully formation 171, 176, 178, 187, 193–194, 195 rhomboid landforms 215–216, 218 layered cones 268, 271 source region 207–208 periglacial 100, 102, 103, 118 terminal distributary systems 211, 212, 220–221 mass-movement, RACs 54, 61, 62 INDEX 305 megaflooding, Lethe Vallis channel networks 220 Phoenix lander see Mars Phoenix lander meltwater 121, 122, 125 phyllosilicates, interior layered deposit (ILD) surfaces 281 in gully formation 173, 195 pingos 88, 111, 117, 123, 126 Meridiani Planum 14,15 pits 13 hematite 1, 281, 297 chains mid-latitudes Sulci Gordii 247–249, 250, 254 ground-ice, distribution 147 Utopia Planitia 139 landscape evolution, Mars and Svalbard 111–126 water ice sublimation, mid-latitudes 11, 133–136, sublimation landforms, subsurface ice 135–141 137, 139, 140, 142 Mojave Crater, fluvial patterns 143–144, 144 Planum Boreum 257 moraines, push 119, 120, 121 Cavi unit 257–258, 259 mounds plate tectonics, lack of 10 fractured 117, 121, 123, 125, 126 platy-ridged-polygonized terrain, Western Elysium layered Basin 203–204, 205, 206, 215, 217, 218, 224– Abalos Colles 259-261, 268–271, 273–274, 275 225 erosion 261, 268 polar caps 10 Western Elysium Basin 203–204 Northern 11 see also Martian Cratered Cones sublimation of water ice 134, 135, 145 polar layered deposits 257–258, 277 Narcissus Crater, Eros 38 polygons Nepenthes Mensae unit 50 equatorial regions 142 Newton Crater, gullies 172 ground-ice thaw processes 88, 91, 92, 100, 106, 121 niveo-aeolian features 122, 123, 125 Svalbard and Mars 115, 116, 118, 124 Noachian Epoch 9 high latitudes, sublimation 134–135, 136 Noachis Terra unit 50 ice-wedge 121 northern hemisphere, surface features 5, 6, 7, 151 mid-latitude 11 Northern Plain, sorted clastic islands 90–91 Pre-Noachian epoch 9 protalus lobes and ramparts obliquity 10, 13 Svalbard 117, 121, 124 effect on gully formation 152–153, 163–164 Thaumasia Highlands 76, 77–78, 79, 80, 81,82 and ground-ice stability 112, 118, 121 and mantling deposit 119, 121, 124 randkluft 57 and sublimation 144–145 regolith observation cryoturbation 87–88, 103, 108 in situ 1, 13–15 liquifaction 102, 103, 105, 107, 108 telescopic 5 Phobos 31, 36 ocean, proposed 9,12–13 properties, effect on sublimation 145–146 Olympus Mons 6, 8, 230 remnant-massif/debris-apron constructs (RACs) aureole deposits 233, 247, 249, 252, 253, 254 Tempe Terra–Mareotis Fossae region 44, 46–47, 48, volcanism 254 49–50, 52–58 OMEGA spectrometer 7,9 age constraints 59–61 Opportunity see Mars Explorer Rover, Opportunity erosion 60–61, 63 outflow landscape evolution 51,61–62 channel networks 11–12 morphometry 58–59, 63 Chasma Boreale 275, 277 resurfacing 54, 62, 63 interior layered deposit (ILD) formation 197 remnant-massifs, Tempe Terra–Mareotis Fossae region 46, 49–50, 51–54 Peneus Planum, sublimation landforms 137, 138–139 resurfacing, remnant-massif/debris-apron constructs Penticton Crater, gullies, slope–area analysis 180, 182, (RACs) 54, 62, 63 185, 187, 188, 190, 192, 193–194 retrogressive thaw slumps 103 periglacial landforms 11 rimaye see randkluft Tempe Terra 43–63 ripples 15 Thaumasia Highlands 69–83 Roche limit 35 permafrost landforms 11 rovers 13,14–15 Svalbard 111–126 Rupes Tenuis scarp 257, 258, 272 Phobos elevation 269–270 escape velocity 30, 36 erosion 259, 261, 265 grooves 21–40 layering 265, 267, 275 age 30 Rupes Tenuis unit 257, 258, 264–266, 268–278 characteristics 24, 26, 27, 28 layering 259, 274–275 Mars Express HRSC image map 22–26 erosion 265, 273–278 morphology 26, 28, 29,30 strike and dip measurement 265–266, 267, 268 origin hypotheses 21–22, 30–39 subunits 257, 266, 274 orbit 21 Russell Crater, gullies 172 306 INDEX

St Elias, Alaska, slope–area analysis 177, 179, 181, sublimation features 184, 186, 191 lobate debris aprons 54–55, 56,61 San Jacinto Fault, California, slope–area analysis 177, Thaumasia Highlands 78 178, 179, 181, 184, 186, 191 Sulci Gordii 229, 230 scallops 121, 134 channel systems 231, 232–255 Utopia Planitia 137–139, 141 age determination 247–251, 252 Scandia region unit 50, 257, 259 aeolian features 249, 251 seasons 10 crater counting 248–251 sedimentology 15 relative stratigraphic order 247–248 SHARAD 82, 262, 271, 273, 277 channel 1A 233, 234, 235, 236, 238, 239, 243 shear-stress incision model 175, 197–198 fluvial origin 253–254 silica, interior layered deposit (ILD) surfaces 281 channel 1B 233, 234, 235, 237, 238, 239, 243 slope–area analysis 174–198 fluvial origin 253–254 data and DEMs 176, 178 channel 2 234, 236–237, 238–239, 240, 243 Earth 177, 178, 179, 181–187, 189, 191, 193 lava origin 253 Mars 176, 180, 181, 182–183, 185, 187, 188, 190, channel 3 234, 237, 239, 241, 242, 243, 243 192, 193–199 fluvial origin 253–254 methods 175–178 channel characteristics 251–254 synthetic crater 183, 185, 188, 190, 192, 193 formation history 254 water sources 196–197 graben 247, 248, 251 wetness index maps 185, 187, 191, 192, 194 islands 241 snow hummock 123 lava, fluid flow 241–243, 246–247, 252 snowpack 119, 120, 123, 125 levees 253 melting 125 study area 232–233 soil creep, slope–area analysis 183, 184, 185, 186, 187, water, fluid flow 240–241, 252 189, 195 width and depth 237–239, 244–245 solifluction 195 sulphates 15 lobes 94, 96–98, 99, 101, 103–104 hydroxylated ferric, interior layered deposit Svalbard and Mars 116 (ILD) surfaces 285, 286–287, 291, Solis Planum 71 294, 297 southern hemisphere, surface features 5, 6, interior layered deposits (ILDs), conversion 7, 151 model 293 Spirit see Mars Explorer Rover, Spirit monohydrated, interior layered deposit (ILD) surfaces Spitzbergen 113, 114 285, 286–287, 290, 291, 294, 296–297 climate 114 polyhydrated, interior layered deposit (ILD) surfaces Stickney Crater, Phobos 26, 33 281, 283, 286–287, 293, 295, 296–297 fracture hypotheses 22, 30–34, 36 Svalbard 113 rolling boulder tracks 22, 30 climate 114 secondary crater chains 21–22, 30 periglacial landforms 111–126 ‘stream power law’ 175 morphological comparison with Mars 114–118 sublimation 133 Swiss-cheese terrain 54–55 differential 146 Syria Planum 70 dust glaciers 121 Sysiphi Cavi 133 effect of fractures and cracks 146 effect of grain size 145 talus, slope–area analysis 183, 184, 185, 186, 187, 194 effect of obliquity 144–145 Tempe Terra effect of regolith properties 145–146 geological setting 47–51 effect of temperature and humidity 145 landscape evolution 51,61–62 effect of wind speed 146 periglacial geomorphology 43–63 ground-ice distribution 145–148 stratigraphy 50–51 karst 103 Tempel I comet 35 landforms 133–148 temperature 10 early investigations 133–134 effect on sublimation 145 equatorial regions 141–144 Terra Meridiani see Meridiani Planum orbital parameters 144–145 Terra Sirenum, gullies, slope–area analysis 180, 183, 190, subsurface ice 192, 195 high latitudes 134–135 terraces, Lethe Vallis 213–214, 217 mid-latitudes 135–141 Tharsis 6, 7, 8 water ice, polar caps 134, 135, 145 formation 9 latitude-dependence 147 glacier moraines 142 process of, experiments and shield volcanoes 229 theory 145–148 Thaumasia Highlands Rupes Tenuis unit 276 faults 81 snowpack 125 geological setting 70–71 INDEX 307

periglacial landforms 69–83 Viking 1 Lander 13 association 78–79, 80 Viking 2 Lander 13–14 debris aprons 76, 78, 80, 82 Viking Orbiter missions 6 erosion 80 volcanism 5, 10 lineated crater-fill 73–76, 78, 79–82 Chasma Boreale area 258, 259 plateau mantling 72–73, 78, 80 Lethe Vallis channel network 224–225 protalus lobes and ramparts 76,77–82 Sulci Gordii area 229, 254 sublimation 78 Western Elysium Basin 204–205 thaw, ground-ice volcanoes 5, 6, 7, 8 high latitudes 87–108 Tharsis 229 Thermal Emission Imaging System (THEMIS) 7, 12 vugs 15 interior layered deposits (ILDs) 283 Rupes Tenuis unit 262, 263 Warrego Rise 70 Sulci Gordii 230, 232, 235–243 Warrego Valles 12, 70, 82 Thermal Emission Spectrometer (TES) 7, 70, 138, water 283, 290 ice 9 thermal inertia, interior layered deposits (ILDs) 283 subsurface, distribution 146–147 thermokarst 88, 100, 102, 103, 105, 107, 133, 140–141 liquid 6 lakes 139 gully formation 173 tidal forces, Phobos, as origin of grooves 22, 34–35 Sulci Gordii channel systems 240–241, 252–253 timescale, geological 9 surface 9,11–13 topography 6–9 see also groundwater; meltwater water sources Utopia Planitia formation of interior layered deposits 296–297 landscape evolution 119 gullies 196–197 sublimation landforms 137–139, 141, 142 interior layered deposits (ILDs) 296 ejecta blankets 141 Western Elysium Basin 203 scalloped terrain 137–139, 141 basin-channel evolution 221–224 mounds 203–204 Valles Marineris 6, 7, 8, 282 platy-ridged-polygonized terrain 203–204, 205, 206, interior layered deposits 281, 284, 287, 292, 294–295 207, 215, 217, 224–225 comparison with chaos regions 295–296 see also Lethe Vallis formation and evolution 293, 296–298 Westfjords, Iceland, slope–area analysis 177, 179, 182, valley fill 184, 186, 191 lineated 43, 52–53, 58, 74 wetness index maps 178, 185, 187, 191, 192, 194 mid-latitude 136 Wild 2 comet 35 valley systems 11, 12 wind 10 flooding 6 effect on sublimation 146 formation 9 Wirtz Crater, gullies 172 valleys, fretted 48, 49, 50, 51, 52 see also hanging valleys yardangs Vastitas Borealis plains 257 Chasma Boreale 277 interior unit 258, 275 interior layered deposits (ILDs) 288, vein ice 93 290, 294