Table 1. Timeline Showing Detection of Aqueous Minerals by Different Mars Orbital Spectroscopic Investigationsa MGS TES MEx/OMEGA Odyssey THEMIS MRO/CRISM, MRO/HiRISE Spatial resolution 6 km/pixel 0.3-2 km/pixel 18 m/pixel VIS, 100 m/pixel IR 18 m/pixel CRISM VISIR, 0.3 m/pixel HiRISE VIS Wavelength 6-50 mum 0.4-5.1 mum 0.4-1.0, 6-15 mum 0.4-3.9 mum Layered phyllosilicates Al and Fe/Mg clays at Nili and Mawrth - Stratification of different compositions; detailed stratigraphy Phyllosilicates in intercrater fans Highland crater fans/deltas contain phyllosilicate-bearing layers Plains sediments Chloride detection Cooccurrence with phyllosilicates in layers Deep phyllosilicates Unknown hydrated mineral in dozens of highland craters - > 5000 outcrops in craters, chasmata; chlorite + other hydrated silicates Intracrater clay-sulfate deposits Sulfates and interbedded clays in highland craters Carbonate deposits Thin layers of hydrous carbonates on olivine-rich rocks Meridiani-type layered deposits Deposits of gray hematite Adjacent occurrences of monohydrated and polyhydrated sulfates - Improved resolution of largely undeformed vertical stratification Valles-type layered deposits Deposits of gray hematite Adjacent occurrences of monohydrated and polyhydrated sulfates - Intricate vertical layering of sulfate types and Fe oxides; folding; alteration zones Siliceous layered deposits Widespread hydrated silica in layered deposits on Hesperian plains Gypsum plains Gypsum-rich optical surface - Relationship to basal unit aAs spatial resolution and wavelength coverage of the data have improved, the diversity of recognized deposits and their known spatial distributions have increased. Data are given for the time during which a class of deposits' existence was known. Hyphens mean there are no new mineral identifications.