Debra Buczkowski, Kim Seelos, Wes Patterson, and Frank Seelos

Mars Landing Sites:Mawrth Vallis

Review: Final 4 (or 5?) Candidate MSL Landing Sites

Holden Crater

Mawrth VallisEberswalde Crater

Gale Crater

Nor

thea

st S

yrtis

East

Mar

garit

ifer

+ one of these may be added at Sept. 2010 workshop

23/30/2010 MESDT

Review: MSL Landing Site Selection Requirements

Engineering Constraints• Latitude…… ± 60°• Elevation…… ≤ 2 km• Ellipse size…… 25 x 20 km• Slopes…… ≤ 3 -15°

(depends on length scale)

• Rock height/abundance……0.6 m/low to moderate

• Winds…… ≤ 10 – 30 m/s (depends on direction and altitude)

• Radar reflectivity…… >-20 db• Load bearing surface……

moderate-high thermal inertia, low albedo = not too dusty

Science RationaleExplore and quantitatively assess a local region on Mars’ surface as a potential habitat for life, past or present

• Context– What is the age and geologic setting of the

site? Possible for observations made by the rover to be put into regional context?

• Diversity of science targets– Are there multiple depositional settings or

mineral assemblages to investigate?

• Habitability– Does the mineralogic and morphologic

evidence support a habitable environment?

• Biopreservation potential– What minerals or depositional structures are

present that might preserve ancient signs of life? 33/30/2010 MESDT

Where is Mawrth Vallis?

Mawrth Vallis

+ many more!43/30/2010 MESDT

24.01ºN341.03ºE

-2.2 km

What’s so interesting about Mawrth?• OMEGA on

Mars Express was the first to discover widespread layered phyllosilicates in Mawrth Vallis

• OMEGA is similar to CRISM, but lower spatial resolution

• Several candidate MSL sites chosen in region

5

HRSC mosaic Unit sketch map3/30/2010 MESDT

Hydration (1.93 μm) Mg/Fe rich phyllosilicate (2.30 μm)Al-OH rich phyllosilicate (2.20 μm)

OMEGA hydrationred = highest concentration

What’s so interesting about Mawrth?• OMEGA on

Mars Express was the first to discover widespread layered phyllosilicates in Mawrth Vallis

• OMEGA is similar to CRISM, but lower spatial resolution

• Several candidate MSL sites chosen in region

63/30/2010 MESDT

Ellipse size – need a safe spot to land

• Regional slope map– Scale = 926 m– Red = steep

• White circles indicate 4 initial sites, all in areas where slopes are good for landing at this length scale

• Downselected site

3/30/2010 MESDT 7

Evaluating Mawrth Vallis

• Science Rationale– Lithologic context of the

phyllosilicate clays?– Age?– Stratigraphic context?– Likely to preserve

biomarkers?– Understandable?

Primary formation modes of phyllosilicates and

pathways in between

83/30/2010 MESDT

Light-toned bedrock is layered, diverse, and complex and deposited over geologically significant duration of time

Mawrth Vallis Geologic Units

93/30/2010 MESDT

HiRISE Images of Light-toned Layers

103/30/2010 MESDT

Layered materials are widespread, contiguous

HiRISE image of landing site

113/30/2010 MESDT

Same light-toned layers observed

regionally

Also notice that there are few, or no, rocks

3/30/2010 MESDT 12

HiRISE image of landing site

Mawrth Stratigraphy

• Light-toned unit has several subunits– Most clay-bearing, but not all

• Dark-toned unit unconformably overlies light-toned unit

3/30/2010 MESDT 13

Evaluation of Light-toned Unit

• Deposited over a geologically significant period of time– Impact craters buried

within unit– Not deposited in a single

catastrophic event

• Heavily eroded– Possibly in the late

Noachian

• Lithified early• Clays formed early

3/30/2010 MESDT 14

Origin of the Clays

153/30/2010 MESDT

Clays are demonstrably associated with a layer that is:

• Thick• Flat-lying• Ancient• Widespread,

undeformed• Geomorphically complex• Deposited over a long

time period

Origin of the Clays

163/30/2010 MESDT

Clay mineral origin not consistent with:

• Impact origin• Expect instantaneous event• Less complete section of

rocks• Recent subaerial weathering

• Expect diffuse pattern of surface composition

• Hydrothermal alteration associated with intrusion• Expect localization• Ties to structure/permeable

conduits

xx

x

Origin of the Clays

173/30/2010 MESDT

xx

x

xx

xClay mineral origin not consistent with:

• Low temperature alteration of lavas• Not consistent with volcanic

structures• Regional metamorphism

• Requires deep burial and re-exposure

• Expect to see deformation• Deep marine environment

• Difficult to reconcile with repeated subaerial exposure

Indicates that early Mars had a much different environment than now

Origin of the Clays

183/30/2010 MESDT

Favored interpretation:• Sedimentary origin at/near

surface• Clays deposited as sediments

(or cements)• Sediments could be of

volcanic (pyroclastic) origin• Associated with sustained

dynamic surface environment• River, lake, or shallow sea

• Diagenetic processes cannot be ruled out• Diagenesis is alteration of

minerals after deposition• Even if diagenetic, clays are

OLD!

xx

x

xx

x

1) Thick complex section gives plenty to explore, but is intact and understandable

2) Clays are as widespread, “abundant” and diverse Within landing ellipse – do not need to “go-to” Chance of preserved biomarkers Possibly deposited in fluvial system or shallow marine

environment Clays could have formed in shallow subsurface diagenesis

3) Uncertain geologic origins, but testable by MSL Imaging will show bedding structures, grain shapes, overall

rock texture Bulk chemistry will show stratigraphic variation In situ identification of minerals Could show organics trapped in a variety of contexts

Summary of Mawrth Science Merits

193/30/2010 MESDT

Engineering and Science Constraint Checklist

Engineering Constraints• Latitude…… ± 60°• Elevation…… ≤ 2 km• Ellipse size…… 25 x 20 km• Slopes…… ≤ 3 -15°

(depends on length scale)

• Rock height/abundance……0.6 m/low to moderate

• Winds…… ≤ 10 – 30 m/s (depends on direction and altitude)

• Radar reflectivity…… >-20 db• Load bearing surface……

moderate-high thermal inertia, low albedo = not too dusty

Science RationaleExplore and quantitatively assess a local region on Mars’ surface as a potential habitat for life, past or present

• Context– What is the age and geologic setting of the

site? Possible for observations made by the rover to be put into regional context?

• Diversity of science targets– Are there multiple depositional settings or

mineral assemblages to investigate?

• Habitability– Does the mineralogic and morphologic

evidence support a habitable environment?

• Biopreservation potential– What minerals or depositional structures are

present that might preserve ancient signs of life? 203/30/2010 MESDT

?

?

CRISM Quickmap view http://crism-epo.actgate.com/ol2wipe/crism_qmap.html

• Multispectral PHY browse mapRed = Fe/Mg phyllosilicatesGreen = Al phyllosilicatesBlue = Hydration

3/30/2010 MESDT 21

CRISM Quickmap view http://crism-epo.actgate.com/ol2wipe/crism_qmap.html

3/30/2010 MESDT 22

• Targeted coverageRed = FRTGreen = HRLBlue = HRS

• Many CRISM images acquired of potential Mawrthlanding sites

CRISM-map Viewhttp://crism-map.jhuapl.edu/

• CRISM verifies OMEGA results + more– abundant and

diverse phyllosilicates and other hydrated minerals in the region

CRISM-map showing regional coverage of hyperspectral targeted images

233/30/2010 MESDT

Next slide

CRISM-map PHY browse productshttp://crism-map.jhuapl.edu/

FRT 89F7

FRT A600

FRT BB59FRT B141

FRT 117BB

FRT B643

HRS 1176A

HRL 11CDD

Red = Fe/Mg phyllosilicatesGreen = Al phyllosilicatesBlue = Hydration

243/30/2010 MESDT

Landing site mineralogy from CRISM

• Orange = Nontronite-bearing

• Yellow = nontronite plus a ferrous component

• Green = montmorillonite/ hydrated silica plus a ferrous component

• Cyan = montmorillonite/ hydrated silica

• Blue = kaolinite3/30/2010 MESDT 25

from McKeown et. al. (2009)

Mineral stratigraphy

• (A) CRISM and lab spectra from images HRL000043EC

• (B) Perspective mineral indicator map– Orange/Red = Fe/Mg-

smectite– Blue = hydrated silica– Yellow/Green = Fe2+

phases• (C) Sketch stratigraphy of

phyllosilicates using the colors from (B).

• (D) Portion of HiRISE image showing textures of different layers

3/30/2010 MESDT 26

from

Bis

hop

et. a

l. (2

008)

OK, so what now?

• Using the CRISM web tools, look for outcrops of distinct, spatially coherent deposits of phyllosilicates, sulfates, or other hydrated mineralogy – Minerals that have been influenced by water, and thus

may reveal something about the ancient history or climate of Mars, or may preserve biosignatures

– If you find an interesting location, use other data sets to evaluate whether it may make a good landing site based on the engineering constraints we’ve talked about

• E.g., a cliff would not be a good landing site even though there may be great exposures of phyllosilicates in the walls

• Although it is too late to be considered for an MSL landing site, any interesting places that you discover could become a future landing site, sample return site, or human settlement site– Often the candidate sites that make it to the final round of consideration

have been in study for a long time

3/30/2010 MESDT 27

For Further Reading and Reference

• Documentation of MSL landing site selection workshops and available data sets: http://marsoweb.nas.nasa.gov/landingsites/

– Recommended presentations from “Third MSL Landing Site Workshop”• Geomorphic Criteria for Defining Depositional Setting by Alan Howard• Preservation of Organic Matter in Phyllosilicates by Lisa Pratt• And others in that section

• NASA ADS reference search tool: http://adsabs.harvard.edu/physics_service.html• CRISM web tools

– CRISM map: http://crism-map.jhuapl.edu/– Quickmap: http://crism-epo.actgate.com/ol2wipe/crism_qmap.html

• Username: sciteam password: yourstuff1

• Context datasets– Mars Orbital Camera (MOC): http://www.msss.com/moc_gallery/– Thermal Emission Imaging System (THEMIS): http://themis.asu.edu/– High Resolution Imaging Science Experiment (HiRISE): http://hirise.lpl.arizona.edu/– USGS : http://webgis.wr.usgs.gov/pigwad/maps/mars.htm

• Nomenclature (does that crater have a name?)– http://planetarynames.wr.usgs.gov/mgrid_mola.html

3/30/2010 MESDT 28