GEO 330 Lecture Notes - Lecture 22: Valles Marineris, Mawrth Vallis, Aureum Chaos
3 Apr 2018
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Document Summary
Both mid-ir (mir) and visible/near-ir (vnir) remote sensing measurements have detected several classes of minerals deposited by water or derived from the interaction of water with primary igneous rocks. Found in meridiani planum (noachian), aram, iani, and aureum chaos (hesperian), and valles. Laboratory experiments show that hematite is probably formed from thermal alteration of goethite ( -feooh), which always forms in water. At meridiani planum, hematite is in the form of spherules, which have been interpreted as concretions. Alternate interpretations include impact melt spherules and volcanic lapilli. Detections in aram, aureum, meridiani, and valles marineris associated with hematite. Most abundant in equatorial regions and often associated with layered terrains like ilds. Fe3+, ca, and mg-bearing sulfates are all present. Presence of sulfates generally inferred to represent an acidic weathering/evaporative environment. Jarosite, an fe3+ sulfate seen at meridiani planum, mawrth vallis, requires a ph < 5 to form.
