Minéralogie de Valles Marineris (Mars) par télédetection hyperspectrale: Histoire magmatique et sédimentaire de la région.

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1 Minéralogie de Valles Marineris (Mars) par télédetection hyperspectrale: Histoire magmatique et sédimentaire de la région. Dr. Jessica Flahaut Chercheur postdoctoral, Institut d Astrophysique Spatiale, Orsay Thèse soutenue le 4/11/11 au Laboratoire de Géologie de Lyon, sous la direction de Cathy Quantin et Pascal Allemand

2 Martian Facts (1) EARTH MARS Mean radius (km) ,5 mass (kg) 5,98* ,24*10 23 Surface gravity (m.s - ²) 9,81 3,72 Heat flux (W.m - ²) Surface temperature( C) 15 (-89 to +60) -63 (-133 to +27) Surface pressure (*10 2 Pa) Fourth rocky planet Differentiated Thin atmosphere Earth Mars Interpretative sketches 2

3 Martian Facts (2) Elevation m MOLA elevation Tharsis Valles Marineris m Age Age distribution 3.0 Gy Amazonian Hesperian 3.7 Gy 4.5 Gy Noachian 3

4 Surface Composition (1) -Martian meteorites (SNCs) - In situ Measurements (Viking, Pathfinder, MERs, Phoenix) - Remote sensing observations (TES, THEMIS, OMEGA, CRISM) 10 cm Bell, 2008 Humphrey (Spirit) 4

5 Surface Composition (2) phyllosilicates, sulfates, other hydrated minerals phyllosilicates, olivine Bibring et al., km Mars surface is globally basaltic, BUT hydrated minerals are commonly detected in local environments. Jezero crater, Ehlmann et al.,

6 The Big Question(s) LCP = low calcium pyroxene HCP= high calcium pyroxene Modified after Mustard et al., 2005 ; Bibring et al., 2006; Carr and Head,

7 The Big Question(s) Change in lava composition? Change in chemistry? Change in climate? Modified after Mustard et al., 2005 ; Bibring et al., 2006; Carr and Head,

8 Valles Marineris, a Key Area (1) MOLA elevation Key facts: - A 4000 km long graben system, west of Tharsis - A natural cut of 11 km through the martian crust -Opening at the beginning of Hesperian 8

9 Valles Marineris, a Key Area (2) MOLA elevation Ius Chasma 9000 m m Hebes Chasma Ophir Chasma Candor Chasma Melas Chasma Juventae Chasma Coprates Chasma Gangis Chasma Capri Chasma Key facts: - A variety of hydrated minerals (Gendrin et al., 2005; Bibring et al., 2006) and terrain ages (Scott and Tanaka, 1986). - Multiple evidence for past water activity (Carr, 1996; Baker, 1982) 200 km Age distribution Noachian, Hesperian, Amazonian 9

10 Datasets and Methods Dataset Mission size (km*km) Spatial resolution (m/px) use MOLA MGS global map Elevation MOC MGS 3* Morphology Themis IR day Mars Odyssey global map 200 Morphology Themis IR night Mars Odyssey global map 200 Thermal inertia Themis visible Mars Odyssey 20* Morphology OMEGA Mars Express variable Mineralogy CTX MRO 30*80 6 Morphology HiRISE MRO 5*10 0,25 Morphology CRISM hypersp MRO 10* Mineralogy CRISM mulitsp MRO 10* Mineralogy Tool = Geographic Information System HiRISE CTX These giant numerical databases allow us to gather different types of images from different sources. THEMIS IR Day CRISM Co-registration example in Candor Chasma 10

11 The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) CRiSM is a push-broom spectral imager. Characteristics: 2 detectors (0.4-1 µm and µm), Spectral resolution: 6.55 nm/channel (544 wavelengths), Spatial resolution: up to 18m/px. 11

12 Approach We surveyed 3 types of environments in and around Valles Marineris: 1- The walls of the canyons (early Noachian - early Hesperian) Flahaut et al., Icarus 2012; Flahaut et al., GRL 2011; MOLA elevation 1 3 Quantin et al., Icarus The surrounding plateaus of Valles Marineris (late Noachian mid Hesperian) 100 km m m Le Deit, Flahaut et al., 2012 N Topographic profile in Capri Chasma S The center of the canyons (mid Hesperian?) Flahaut et al., Icarus 2010; Flahaut et al., JGR 2010; Fueten, Flahaut et al., JGR Their composition Geological evolution of the region 12

13 Insights into the analysis of VM walls CRISM FRT00009DB4 Fe/Mg Phyllosilicates Olivine Low Calcium Pyroxene 1 km Mineralogic parameters Library Olivine Phyllosilicates Orthopyroxene Olivine Reflectance Library Saponite Exposed pristine bedrock dike Library orthopyroxene Flahaut et al., Icarus 2012 Wavelength (µm)

14 Dikes 50 m HiRiSE PSP_010712_1660 CRISM FRT00009DB4 RGB (R=Olindex2, G=LCPindex, B=D2300) 50 m Flahaut et al., GRL

15 Fan with head valley 5 km Water and sediments in VM Multiple terraces THEMIS IR Day mosaic Bright outcrops Chaotic floor 2 km CTX Line streaks 10 km 50 km THEMIS_VIS Flahaut et al., Icarus 2010 Line streaks 10 km THEMIS_VIS 10 km

16 Walls LCPenriched crust Main Conclusions Walls clays Plateaus clays Capri s ILDs Capri s morphologies Modified after Mustard et al., 2005 ; Bibring et al., 2006; Carr and Head, 2009 Valles Marineris: The oldest rocks on Mars surface + a unique record of Mars history. 16

17 Thank you for your attention! Questions?