Habitability of a Large Ghost Crater in Chryse Planitia, Mars

Chryse Planitia

Mars Pathfinder

Viking 1

MER Opportunity

Habitability of a Large Ghost Crater in Chryse Planitia, Mars

Dorothy Z. Oehler & Carlton C. Allen

Astromaterials Research &Exploration Science Directorate (ARES)

NASA - Johnson Space CenterHouston, Texas , U.S.A.

Support from ARESand

ARES Mission Enabling Grant

Oehler & Allen, Exploring Mars Habitability, June 14, 2011

HABITABILITY - GEOLOGIC CONTEXT

Long-Lived H20• Run-off or upwelling sources• Container (basin or lake) to trap

Liquid H20• Early Mars • Enhanced heat flow

Regional (e.g. Tharsis) Hydrothermal vents Impact-related hydrothermal circulation -

craters > 100 km (Newsom et al. 2001; Pope et al. 2000, 2006; Abramov & Kring 2005; Schwenzer et al. 2009; Ivanov & Pierazzo 2011)

Renewing Nutrients • Run-off -- catchment• Upwelling (groundwater / hydrothermal)

Quasi Circular Depressions

(QCD’s)

Outflows

Chryse Planitia

Acidalia Planitia

HABITABILITY CRITERIA

GEOLOGIC CONTEXT


GEOLOGIC CONTEXT: Drainage - Upwelling

CatchmentEstimated from valley networks(channels from Carr; USGS MarsGIS)

Global Hydrology Noachian - E. Hesperian groundwater

upwelling predicted in Chryse & Acidalia (Andrews-Hanna et al., 2007, 2011)


Elevation> -1800 m

< - 4850 m

Legend

mola_mud_volcanos

megt90n000eb.tif

Value

High : -1800

Low : -4850

mola_128deg_270e_hillshade.jp2

Value

High : 210

Low : 115


Value

High : 255

Low : 0

OUTFLOW CHANNELS• Late Hesperian

GEOLOGIC CONTEXT - Setting of Ghost Crater

CRATER120 km diameter;

Subdued (“ghost”/“stealth”)

Noachian - Late Hesperian (~Early Hesperian)

34oN, 37oW


Viking 1

Mars Pathfinder

500 km

30oN, 30oW

60oN, 30oW

MOUNDS> 18,000 mapped

40,000 estimated

Oehler & Allen, 2010., Icarus 208, 636-657.

Elevation> -1800 m

< - 4850 m

GEOLOGIC CONTEXT - Setting of Ghost Crater


500 m

MOC S05-00934

PSP_001916_2220

PSP_008548_2205

350 m

500 m

500 m

PSP_007770_2205

PSP_008522_2210

350 m

N

Chryse-Acidalia Mounds: Mud Volcano Analog

PSP_008483_2250

250 mMOC E21-00561

500 m

P18_008021_2271

500 m

PSP_008548_2205

250 m

500 m

500 m

P19_008483_2246 P17_007849_2255

500 m


Geologic Units

ACIDALIA

Vastitas Borealis Marginal Unit

CHRYSE

Vastitas Borealis Interior Unit

Vastitas Borealis(Kreslavsky & Head, 2002; Tanaka et al., 2005)

• Late Hesperian/ Early Amazonian - product of outflows

• Polygons, mounds, ghost craters - modification

• Outer margins constant elevation - groundwater table - or -

emplacement in a standing body of water


FACIES

Elevation> -1800 m

< - 4850 m

Legend

mola_mud_volcanos

megt90n000eb.tif

Value

High : -1800

Low : -4850


Value

High : 210

Low : 115


Value

High : 255

Low : 0

Proximal

DistalFine-grained sediments;

organic matter

Coarse-grained sediments


Knobsat Rim

Mounds within Crater Fill

P21_009353_2156

5 km

50 km

GHOST CRATERRIM: Large knobs, irregularly shaped, lobate - possible hydrothermal circulation from impact

INTERIOR: ~ 1000’s m fill with giant polygons & smaller, circular mounds

Polygonal Fractures


CRATER FILL

GIANT POLYGONS: 1-10 km

MOUNDS:

• 0.25- 0.8 km diameter• pitted• central vents • circular • high albedo• moats • concentric form to crest• possible flow structures

Similar to mounds in Acidalia. Mud volcano analog.

5 km

P22_009498_2136


MOUNDS: Possible flow structures, concentric shape, younger than polygons

1 km 1 km

P22_009498_2136 P22_009498_2136

500 m 500 m

P22_009498_2136 P22_009498_2136


Mud Volcanism

Mud volcanism creates microhabitats in the subsurface:

• fracturing sediments

• providing pathways for fluid migration


CONCLUSION - High Potential for Habitability

WHY EXCEPTIONAL? Combination of LARGE SIZE and LOCATION (lowlands, outflows, distal facies)

HIGHEXPLORATION POTENTIAL

• Enhanced habitability

• Potential to include organics

• Potential of mud volcanoes to bring sediments from depth to the surface


Documents

Habitability of a Large Ghost Crater in Chryse Planitia, Mars