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Broad Perspectives on Preferred Types of Mars Science Laboratory Landing Sites: Experience from Characteristics of Previous Landing Sites and Developing Sedimentologic Facies Models M. Golombek and J. Grotzinger Jet Propulsion Laboratory and Caltech. - PowerPoint PPT Presentation
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Broad Perspectives on Preferred Types of Mars Science Laboratory Landing Sites:
Experience from Characteristics ofPrevious Landing Sites and Developing
Sedimentologic Facies Models
M. Golombek and J. GrotzingerJet Propulsion Laboratory and Caltech
Golombek & Grotzinger’s Guide to MSL Landing Sites
• Layered Sedimentary Rocks– Extensive Section
• Outcrop, No Float – Not Hesperian or More Cratered Surface
• No/Little Dust– Dark, Low Albedo
• Low Energy Depositional Sedimentary Facies– Clay rich mudstones distal fluvio-deltaic or
lacustrine– Bottom-growth evaporites - sulfates
MSL Science Objectives• Focus on Habitable Environment
• PP Requirements Focus on Ancient Habitable Environments
• Layered Sedimentary Rocks– Well Suited to Address Ancient Environments
• Meridiani Planum Sulfates– Top of Section of Layered Sedimentary Rocks – Formed in Late Noachian – Approximately Coeval w/Geomorphic Indicators
• Valley Networks, Eroded Terrain, Layered Rocks
– Formed in Wet, Likely Warm Environment
VL1 MPF
Meridiani
VL2
Gusev
Landing Sites on Mars5 “Ground Truth” Samples
15°N
15°S
Meridiani Eroded Highlands
Meridiani Planum Site
Smooth Plains Overly Noachian Cratered Terrain
Generally Bury Valley Networks flow to NW, Down Topographic Slope Created by Tharsis Loading
Population Old Degraded Craters >1 km Diameter are Noachian
Lightly Cratered Indicates Young Surface Age
Bright Unit Mapped As Package of LN Sedimentary RocksSurface Age Late AmazonianHesperian Craters GoneErosion of 10-80 m of Material
Meridiani
Hynek, 2004
Meridiani Planum Late Noachian Denudation
Hynek and Phillips [2001]
~1 kmErosionin LN[Just beforeEvaporites Deposited]
Argued forPrecipitation& Runoff
Warm and WetEnvironment
MeridianiPlanum
Late NoachianSulfates“Dirty Evaporites”
Liquid WaterStable
Wet andLikely WarmEnvironment
Dells MI Mosaic
Dirty Evaporites Document Early Wet & Likely Warm Environment
Overgaard
Lowerunit Middle unit
Upperunit
BurnsFormation
Network of Interdune Depressions
Interdune Depression
100 km
MSL to Layered Sedimentary Rocks
Likely Formed in Wet and Warm Conditions and Record Aqueous EnvironmentOMEGA Identified Sulfates in Many Such TerrainsSubstantial Stratigraphic Section Accessible [Meridiani ~10 m]
No Float!
Outcrops OnlyInstructions on Door of JPL 183-803, 1998 to present
Occupant: T. Parker
No Float/OutcropGusev Hesperian Cratered Plains
Gusev Random Sample Hesperian CrateredPlains
Variable ThicknessImpact Generated Regolith
Likely Formed as Lava Flows
No Outcrop Found
Cratered
Plains
Cratered Plains
Angular Basalt
Fragments
Likely Basalt Flows
Impact Generated
Regolith
Bonneville
Fresh Crater, Fresh Ejecta, Little evidence for BackwastingNo Debris Chutes or Talus, Jumbled Regolith of Basalt Ejecta ~10 m ThickNo Outcrop
Viking Lander 1
Late Hesperian Cratered Surface
Limited Low Outcrop
Lot of Rock Float
No OutcropRocks are Float
Viking Lander 2
Lightly Cratered Surface forIntact Stratigraphy
Cratered Surface: Beware of Float, Regolith and No/Little Outcrop
No Dust, Dark Low-Albedo Site
Meridiani - First Landing Site in Dark Region, Albedo Low ~0.1
Basalt Sand, Hematite Granule Lag Surface Ripples
No/Little Dust to Mask Remote Sensing; More Effective Surface Operations to ID Rocks & Soils to Investigate Further
Sedimentary Facies• Low Energy Environments
– Maximize Accumulation & Preservation of Biomarkers– Burns Formation at Meridiani
• Most High Energy Sand Dune and Sand Sheet• Not Optimal for Accumulation or Preservation
• Two Optimal Facies– Clay Rich Mudstones: Deposited in Distal Fluvio-
deltaic or Lacustrine Setting– Bottom Growth Evaporites– Examples of Each & How to Recognize
• Ideal Landing Site Has Both Facies
Eolian Dune
Sand Sheet
Interdune
Sulfate (Gypsum) Evaporites in Playa Lake
Microbial Mats Being Entombed, Could Protect from Degradation (Salts Impermeable)Chemical sediments have high potential to preserve organic compounds
Microbial Mat Textures Preserved in Evaporites
Example of Layered SulfatesHeadwaters of Maja VallesFloor Around -2 km Elevation4.5°S, 297.5°E
Juventae Chasma
4S
297E
5S
296.5E
Juventae Chasma Layered Deposits
Gypsum (Ca Sulfate)
Kieserite Mg Sulfate)
Stratigraphic Transition -Minerals with Different SolubilitiesBibring et
al. 2005
Land and Traverse on Sand SheetSample Stratigraphic Column
200 m
On Earth, organic material preferentially sequestered by clay minerals Preservation organics enhanced by phyllosilicate surfaces
Search Strategy - Look for phyllosilicates in spectral imaging and Stratal Geometries to Identify Distal Environments - Clays and Organics
Example Distal Clay Rich SiteClinoforms
Channel
Clinoforms ClinoformsPrograding Delta
Prograding Clinoforms
Condensed Section, Decrease in Grain Size, Distal Clay RichEnhanced Organic Accumulation and Preservation
Prograding Clinoforms
Yellow Lines Define Single Depositional Sequence
Convergence of Clinoforms - Section CondensationDecrease in Grain Size
Accumulation of Clay Minerals and Organics
Depositional Sequences• Conformable succession of genetically-related
strata, bounded at the top and base by:– Unconformities (surfaces of erosion) or their– Correlative conformities (surfaces lacking erosion)
Sequence Stratigraphy
Seismic Reflection Data - Prograding Clinoforms
Sequence Boundaries - Stratal Truncations and Onlap Define Cinoforma
Interpretation of Facies - Brown Shales, Downdip of Sands
Permian Clinoforms in Last Chance Canyon
Permian Clinoforms in Last Chance Canyon
Golombek & Grotzinger’s Guide to MSL Landing Sites
• Layered Sedimentary Rocks– Extensive Section, Intact Stratigraphy, Known Geologic
Setting - Related to Geology of Mars
• Outcrop, No Float, Lightly Cratered– Not Hesperian or More Cratered Surface
• No/Little Dust, Effective Surface Remote Sensing– Dark, Low Albedo
• Low Energy Depositional Sedimentary Facies– Clay rich mudstones distal fluvio-deltaic or lacustrine
setting, Look for clays and clinoforms– Bottom-growth evaporites - sulfates, extensive
stratigraphic section, better chance to find bottom growth