Download - Mawrth Vallis Location - NASAmarsnext.jpl.nasa.gov/documents/LandingSiteWorksheet_Maw...Horgan B. (2016) Strategies for searching for biosignatures in ancient martian sub-aerial surface

M2020CandidateLandingSiteDataSheets MawrthVallis

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Mawrth VallisLocation(lat,lon):

24°N,341°E

Summaryofobservationsandinterpretedhistory,includingunknowns:

TheMawrth Vallis region contains extended outcrops of phyllosilicate-rich rocks. OMEGA and CRISMhavedetectedFe/Mg-smectites,Al-smectites,kaolinite,hydratedsilica,andsulfatesinassociationwithlight-tonedexposuresofNoachianbedrock.TheMawrthVallissitewouldenableinvestigationofsomeofthemostancientoutcropsofsedimentaryandclay-bearingrocksonMars.

Theclay-bearingunitscorrespondtoexposuresofthick(>300m),finelylayered(layerthickness<<10m)sedimentaryrocksextendingacrossa300*300kmwideregion.Theoriginofthe layering isunknown:interpretationsincludesubaqueous,fluvialandvolcaniclasticdeposits;theorbitalfaciesdoesnotallowadefinitive interpretation.Thisunit isdominatedbyFe/Mgsmectiteswith local interbedsofsulfates.OMEGAandCRISMunmixingmodelssuggestclaymineralabundancesashighas50wt.%.ItisuncleariftheFe/Mg-smectitesarerelatedtotheglobalpopulationofcrustalNoachianFe/Mg-smectites.

SomeportionsoftheFe/Mg-unitexhibitlargeresistantfilledfracturesandhalo-boundedveinsthatareinterpreted to have formed due to fluid circulation. The close proximity of the large Oyama crater,which impacted into the Fe/Mg-unit, suggests that these may be impact hydrothermal deposits;however,low-Tgroundwaterdiagenesiscannotberuledoutbasedonorbitaldata.

Al-richclays,gradingfromAl-smectiteandsilicaintokaoliniteandpossiblyallophane,dominatethetop10-30m of the section. The Al-clays are interpreted to have formed during sub-aerial weathering(pedogenic leaching). However, significantmineralogical variability as well as features interpreted asinverted channels suggest that the surface supported aqueous environments. The kaolinite isconcentratednear the topof the section,andmayeitherhavebeen formeddue to (a) localizedacidleaching ina “wetland”environment, (b) regionalorglobalacid surface leaching, (c) long term,moreneutralleaching(alaterite).Possiblealunitedetectionsatthetopofthesectionsupporteitherscenario(a) or (b). Strong spectral signatures consistentwith Fe(II)-bearing phyllosilicates associatedwith thekaolinitemaysupportreducing,poorlydrainedconditions,butthespectralsignatureisnon-unique.

TwoscenarioshavebeenproposedfortheoriginoftheAl-unit:(1)TheAl-unitpostdatestheunderlyingFe/Mgclaysandthecontact isanunconformity;(2)TheAl-unit istheresultof intenseleachingofthepre-existing Fe/Mg-clays. The contact between the units is often also characterized by a spectralsignature that is consistentwith Fe(II)-bearing phyllosilicates, possibly indicating alteration by Fe-richreducinggroundwater. Insomelocations,closeproximityto jarositeandcopiapitemayimplyastrongFe/Sredoxgradient,possiblyduetooxidationatsub-aerialseeps(Farrandetal,2014).

Theclaysarecappedbyaregionally-extensivedarkmesa-formingunit thatexhibitspyroxenespectralsignatures.Thisunitmayeitherbeapyroclasticdepositoramaficsandstone.Fromcratercounts,thecap rock is3.7Gyold (EarlyHesperian).TheAl-unitpredates thisepisodeand is interpretedasbeingLateNoachianwhereasthethickerlayereddepositsweredepositedbefore(MiddleNoachianorearlier).


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Summaryofkeyinvestigations

- Establishthecomposition,natureandoriginoftheclay-bearingdepositsinsidetheellipse.

- Determinethenatureoftheterminalaqueousenvironment;searchforbiosignaturesinassociationwithsulfatesandreducedironalterationphases

- DeterminewhetherornotmineraldiversitycorrespondstoNoachianclimatevariationsandconstrainnatureofNoachianclimate

- Searchfororganicsintheseclay-bearingdeposits,atpaleosurfaces,mineralsprecipitatedatseeps,andinsurfaceaqueousenvironments

- Determinetheoriginoffilledfractures;searchforbiosignaturesinprecipitatedminerals

- Determinenatureandcompositionofthedarkcaprock;ifvolcanic,sampleforagedating

CognizantIndividuals/Advocates:

DamienLoizeau,BrionyHorgan,FrançoisPoulet,NicolasMangold,JaniceBishop

LinktoWorkshop2rubricsummary

https://docs.google.com/spreadsheets/d/16Rmn2qHFQc6BKJtiyIeDLcyBxJqq8Oq4VO3etqrZ8lo/edit?invite=CNm8lqYF&pref=2&pli=1#gid=868597987

KeyPublicationslist(groupedbytopic):

Mineralogy:Bishop,J.L..etal(2008)PhyllosilicateDiversityandPastAqueousActivityRevealedatMawrthVallis,Mars.Science321,830.DOI:10.1126/science.1159699.

Bishop,J.L.etal(2013),WhattheancientphyllosilicatesatMawrthValliscantellusaboutpossiblehabitabilityonearlyMars,PlanetaryandSpaceScience,86,130–149,doi:10.1016/j.pss.2013.05.006.

Bishop,J.L.,andE.B.Rampe(2016),EvidenceforachangingMartianclimatefromthemineralogyatMawrthVallis,EarthandPlanetaryScienceLetters,448,42–48,doi:10.1016/j.epsl.2016.04.031.

Farrand,WilliamH.;Glotch,TimothyD.;Rice,JamesW.;Hurowitz,JoelA.;Swayze,GreggA.(2009)DiscoveryofjarositewithintheMawrthVallisregionofMars:ImplicationsforthegeologichistoryoftheregionIcarus,Volume204,Issue2,p.478-488.DOI:10.1016/j.icarus.2009.07.014.

Farrand,W.H.,T.D.Glotch,andB.Horgan(2014),DetectionofcopiapiteinthenorthernMawrthVallisregionofMars:Evidenceofacidsulfatealteration,Icarus,241(C),346–357,doi:10.1016/j.icarus.2014.07.003.

Loizeau,D.etal(2007).PhyllosilicatesintheMawrthVallisregionofMars.JournalofGeophysicalResearch,Volume112,IssueE8,CiteIDE08S08.DOI:10.1029/2006JE002877.

McKeown,N.etal.(2009)CharacterizationofphyllosilicatesobservedinthecentralMawrthVallisregion,Mars,


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theirpotentialformationalprocesses,andimplicationsforpastclimate.JournalofGeophysicalResearch,Volume114,Issue52,CiteIDE00D10.DOI:10.1029/2008JE003301.

Poulet,F.etal(2008).NewevidenceofsignificantabundanceofclaymineralsonMars.A&A487,L41–L44.DOI:10.1051/0004-6361:200810150.

Wray,JamesJ.etal(2010)IdentificationoftheCa-sulfatebassaniteinMawrthVallis,Mars.Icarus,Volume209,Issue2,p.416-421.DOI:10.1016/j.icarus.2010.06.001.

StratigraphyandPhysicalProperties:Howard,A.D.;Moore,J.M.(2007)TheLight-tonedSedimentsinandnearLowerMawrthVallisMaybeaDrapeDeposit.38thLPSC,p.1339.

Loizeau,D.etal.(2010)StratigraphyintheMawrthVallisregionthroughOMEGA,HRSCcolorimageryandDTM.Icarus,Volume205,Issue2,p.396-418.DOI:10.1016/j.icarus.2009.04.018.

Michalski,J.R.;andE.Z.NoeDobrea.2007.EvidenceforasedimentaryoriginofclaymineralsintheMawrthVallisregion,Mars.Geology,October2007;v.35;no.10;p.951–954;doi:10.1130/G23854A.1

Michalski,JosephR.;Fergason,RobinL.(2009)CompositionandthermalinertiaoftheMawrthVallisregionofMarsfromTESandTHEMISdata.Icarus,Volume199,Issue1,p.25-48.DOI:10.1016/j.icarus.2008.08.016.

Wray,J.J.etal(2008)Compositionalstratigraphyofclay-bearinglayereddepositsatMawrthVallis,Mars.GeophysicalResearchLetters,Volume35,Issue12,CiteIDL12202.DOI:10.1029/2008GL034385.

Astrobiology:Bishop,J.L.etal(2013),WhattheancientphyllosilicatesatMawrthValliscantellusaboutpossiblehabitabilityonearlyMars,PlanetaryandSpaceScience,86,130–149,doi:10.1016/j.pss.2013.05.006.

Horgan,B.H.,etal(2015),PossibleMicrobialEnergyPathwaysFromIronandSulfurRedoxGradientsatMawrthVallisandGaleCrater,Mars,AstrobiologyScienceConference,#7463,doi:10.1126/science.12.

HorganB.(2016)Strategiesforsearchingforbiosignaturesinancientmartiansub-aerialsurfaceenvironments,BiosignaturePreservationandDetectioninMarsAnalogEnvironments,#XXXX.

Regional/GlobalContext:Carter,J.Loizeau,D,Mangold,N.,Poulet,F.,Bibring,J.-P.,2015,WidespreadsurfaceweatheringonearlyMars:acaseforawarmerandwetterclimate,Icarus,248,373-382,doi:10.1016/j.icarus.2014.11.011

Loizeau,D.etal(2012)Characterizationofhydratedsilicate-bearingoutcropsinTyrrhenaTerra,Mars:ImplicationstothealterationhistoryofMars.SubmittedtoIcarus.

NoeDobrea,E.Z.etal.(2010)Mineralogyandstratigraphyofphyllosilicate-bearinganddarkmantlingunitsinthegreaterMawrthVallis/westArabiaTerraarea:Constraintsongeologicalorigin.JournalofGeophysicalResearch,Volume115,IssueE11,CiteID,E00D19.DOI:10.1029/2009JE003351.

Poulet,F(2005).PhyllosilicatesonMarsandimplicationsforearlymartianclimate.Nature,Volume438,Issue7068,pp.623-627.DOI:10.1038/nature04274.

Landingsitestudies:Loizeau,D.etal(2015).Historyoftheclay-richunitatMawrthVallis,Mars:High-resolutionmappingofa

candidatelandingsite,JGR-Planets,10.1002/2015JE004894.Michalski,J.(2010)TheMawrthVallisRegionofMars:APotentialLandingSitefortheMarsScienceLaboratory(MSL)Mission.Astrobiology,Volume10,Issue7,pp.687-703.DOI:10.1089/ast.2010.0491.


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RegionalContextFigure(ref:Loizeau)


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EllipseROIMaporGeologicMapFigure(ref:Loizeau,MCKeown)

Red:Fe/Mg-smectites

Blue:Al-clays

Green:ferrousalterationphases


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Regional(~3xellipse)StratigraphicColumnFigure


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InferredTimelineFigure

SummaryofTop3-5Units/ROIs

ROI AqueousorIgneous?

Environmentalsettingsforbiosignaturepreservation

Aqueousgeochemicalenvironmentsindicatedbymineralassemblages

1.Claystratigraphy

Aqueous Pedogenic,fluvial,possiblewetlands;Pedogenic/diagenetic/subaqueousclays;subsurfaceaquifersandseeps

Al-clays/alunite/ferrousclays/silica;Fe/Mg-smectites;ferrousclays/jarosite

2.Halo-boundedfractures/veins

Aqueous Impacthydrothermalsystemorsubsurfacelow-Tfluidflow

--

3.Darkcappingunit

Igneous Maypreserveunderlyingpaleosurface&surfacecommunities

Pyroxene-bearingdarkdeposits

4.Elongatedmesas

Aqueous Fluvial --


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Top3-5Units/ROIsDetailedDescriptionsUnit/ROIName:1.Claystratigraphy

Aqueous

Description:

● Predominantthick(upto300m)clay-bearingunitcomposedofFe-Mgsmectites,changestoAl-clays(Al-smectites,kaolinite),andsilicaintop10-30m.

● Ferrousphasesandoxidizedsulfatesincloseproximity.● Maintargetofinterestisthetopofthesequenceandtheterminalaqueousenvironment.

Interpretation(s):

● Originofdepositionofsedimentsisunclear:lacustrine,fine-grainedeolian,ashcanexplainthedepositionstyle.Fluvialandeoliancrossbeddingnotobserved.Localejectafromcratersareinterbeddedwithlayers,suggestinglongtermdeposition.

● Fe/Mg-smectites:Originofthealterationintoclaysincludesdiageneticalteration(authigenicclaysonanypreviouslydepositedsediments)ordetritalclaysifsubaqueousdepositionwaspredominant.

● Al-unit:Pedogenicweatheringsequenceformedunderatemperateclimate,formedeitherasadeepleachingprofileofasingledepositionalunitorasapaleosolsequence(weatheringconcurrentwithlong-termdeposition).Kaoliniteattopofsequenceeitherindicateslong-livedleachedpaleosurface(laterite)orweatheringinacidicwetlands.

● Ferrousalterationphasesproximaltolocalizedsulfates(jarositeandalunite)suggestsanFe/Sredoxgradientinsurfacewetlands(Al-unit,terminalaqueousenvironment)andinsubsurfaceaquifersandsprings(contactbetweenFe/Mg-andAl-units).

InSituInvestigations:

● EvaluatethehabitabilityofEarlyNoachiantoEarlyHesperiansurfaceandsubsurfaceenvironments

● Establishthenatureandoriginoftheregionalclayrichbasement—crustallow-Thydrothermalalteration,magmatic/impactalteration,pedogenicweathering,etc.

● InterrogatetheoriginofAlphyllosilicates—weatheringzonesindicatingclementtemperatures;zonesofacid-leaching.


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● Determinewhetherornotredoxgradientsexistedandtheirorigin—groundwaterfluctuations,chemicalreactionsbetweenunits,oxidizingatmosphere,etc.

● Determineoriginofapparentlayering,searchforpreservedpaleosurfacesandpaleoenvironments

● DeterminewhetherornotmineraldiversitycorrespondstoNoachianclimatevariationsandconstrainnatureofNoachianclimate

● Insitufaciesatmetertomm-scaletodeterminefacies,grainsizesandtexture.● Chemo-stratigraphytoconstrainthealterationorigininbothunits.● Searchfororganicsinterminalaqueousenvironment-concentratedinreducing(e.g.,ponded)surfaceenvironmentsasindicatedbyferrousphasesorinfluvialdeposits(overbanks,floodplains,etc.)

● Searchforpaleosurfaceswhereorganicscouldhaveaccumulated● Searchfororganicsandmorphologicalbiosignaturesassociatedwithsulfatesandsilica● RIMFAXtomaptheinternalstructureoflayereddeposits;searchfordiscontinuities(e.g.stronger/weakerreflections)andlateralchangesinlayering.Ifpossibledeterminedensity,internalrockabundanceofthelayerstohelpdetermineorigin.Examinestructureofcontactwithunderlyingbasementunits

● RIMFAXtosearchforinternallayering;examinecontactwithlowerunits.

ReturnedSampleAnalyses:

● Precipitatedminerals,ifpresent,wouldrecordatmosphericcompositionwithinpaleo-weatheringsequences,enablingevaluationofstableisotopesofauthigenicmineralsfortemperature,changingatm/waterchemistry

● Organicsextractedfromclaymineralscouldbeexaminedasafunctionoftimetosearchforbiosignaturesandunderstandthepaleo-influxofexogenousorganicmatter

● Samplesulfatesforstableisotopestudiesthatconstrainfluid/atmosphericchemistry● Retention/depletionofredoxsensitiveminorandtracemetalswouldconstrainatmospheric/aquiferredoxandchangeswithtime

● Mineralassemblages,detailedpetrology,andstableisotopeswouldconstraintheoriginoftheclaysbyweatheringorhydrothermalactivity

● Iflayersareigneousinoriginandretainprimarymaterials,evaluateevolutionofigneousprocessesovertime


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Unit/ROIName:2.Halo-boundedfracture-fills

Aqueous

Description:

• 10mwidefracturefillsthataremoreresistanttoerosionthantheclay-bearingrocks.• Fracturestransitiontoerodedveinsinsomelocations.• Ahalowithdistinctcolorispresentaroundthefracturesandveins.

Interpretation(s):

● ImpacthydrothermalsystemduetoOyamacraterimpactduringperiodbetweendepositionofFe/Mg-unitandAl-unit–impactmayhavecausedbothfracturingandfluidflow.

● Alternatively,precipitationinfracturesduetolow-Tsubsurfacediagenesis.


● Usemorphology,mineralogy,geochemistrytodetermineoriginoffracturefills● Evaluatehost-rockforsignsofimpactdisturbance● Searchfororganicandmorphologicalbiosignaturesinprecipitatedminerals● RIMFAX to seek reflections from fracture fills; if detectable, examine subsurface

geometry. Map subsurface layering on either side of the fracture fills.


● Precipitatedmineralsinfractures-searchforisotopicandotherbiosignatures,evaluatefluidchemistryfromtrappedfluids

Unit/ROIName:3.Darkcaprock

Igneous(rockwaypoint)

Description:Darkcaprock,pyroxenebearing,locallythinlylayeredormassive.Neverexceed20-30minthickness.Typicallyfillstroughsandcraters.Oftenasinvertedtopography(somoreresistantthanclay-bearingdeposits)

Interpretation(s):


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● Eithereolianorigneous(pyroclastic)deposits;regionalextentregardlessoftopographyismoreconsistentwithpyroclasticorigin.

● Exhibitsstrongpyroxenespectralsignatures,nosignsofalteration● Non-alteredmaterialdepositedafterendofalterationinthisregion● Cratercountssuggest3.7-3.6Ga(EarlyHesperian)


● Analyzefacies/texture/mineralogytodetermineigneousvs.aeolianorigin● RIMFAXtoseek reflections from base of cap rock deposits; if detectable, examine

subsurface geometry and contact with surrounding layers. If possible, determine density of deposits, search for internal large blocks that could help determine origin.


● Unalteredmaterialforgeochronology;constraincriticalEarlyHesperiantiming● Igneouspetrology

Unit/ROIName:4.Mesachains

Aqueous

Description:LinesofelongatedmesasorientedalongregionalslopeinOyamacrater

Interpretation(s):

● Invertedvalleyspreservingterminalaqueousenvironment


● Searchfororganicsinanypreservedoverbankdeposits,floodplains,etc.● Sedimentologytoconstrainseasonality,durationofterminalaqueousenvironment


●


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Biosignatures(M2020ObjectiveBandObjectiveC+e2e-iSAGType1A,1Bsamples)

BiosignatureCategory

InferredLocationatSite Biosig.Formation&PreservationPotential

Organicmaterials Inassociationwithpaleosurfaces,withinclay-bearingunits,inassociationwithreducedphasesandprecipitatedminerals,withinfilledfractures

Rapidlyburiedpaleosurfacescanpreserveorganicsfromsurfacecommunities;Claymineralsareabletopreserveorganics;reducingenvironmentspreserveorganics;preipicatedmineralspreserveorganics

Chemical Clay-bearingunit,Fe-MgandAlunit,Haloboundedfracturefills

ZonationinchemistryinthetransitionfromFe-MgtoAlclaysunit.Roleofthereduced(ferrous)horizon.

Isotopic Claybearingunit,darkcapunit,fracturefills

Lightisotopesinclays

Mineralogical All MIneralizationinhalos,zonationswithspecificminerals

Micro-morphological Fe-Mgclaylayeredunit,precipitatedminerals

Anystructurepreservedinclaydepositsorprecipitatedminerals

Macro-morphological Al-richclayunit Matspreservedinpaleosurfaces

DateableUnit(s)forCrateringChronologyEstablishmentUnitName

TotalArea(km2)

TimePeriod

GeologicInterpretationanduncertainties

Whatconstraintswouldtheunitprovideoncraterchronology?

Darkcaprock

Regionalinextent

EarlyHesperian

Couldbeeoliandepositsfromreworkedigneousrockorpyroclasticdeposits;regionalextentmaybemoreconsistentwithpyroclastics

Wellconstrainedstratigraphicunitwithregionalextent.However,ifthisisprimaryvocanicisunclear.


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KeyUncertainties/UnknownsabouttheSiteListthemostimportantuncertainties,unknownsorpotentialdrawbacksaboutthesite

● PoorlyconstrainedoriginoftheFe-Mgrichlayereddeposits

● Noobviousgeomorphicevidenceofstandingbodyofwater

● Oyamacratermayhavedisturbedthedeposits(althoughitcouldalso

haveprovidedaheatsourceforahabitableimpact-generatedhydrothermalsystem)