mawrth vallis location - nasamarsnext.jpl.nasa.gov/documents/landingsiteworksheet_maw...horgan b....
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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.
InSituInvestigations:
● 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.
ReturnedSampleAnalyses:
● 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)
InSituInvestigations:
● 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.
ReturnedSampleAnalyses:
● Unalteredmaterialforgeochronology;constraincriticalEarlyHesperiantiming● Igneouspetrology
Unit/ROIName:4.Mesachains
Aqueous
Description:LinesofelongatedmesasorientedalongregionalslopeinOyamacrater
Interpretation(s):
● Invertedvalleyspreservingterminalaqueousenvironment
InSituInvestigations:
● Searchfororganicsinanypreservedoverbankdeposits,floodplains,etc.● Sedimentologytoconstrainseasonality,durationofterminalaqueousenvironment
ReturnedSampleAnalyses:
●
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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)