Martian Geochronology from Meteorites and Crater Counts

L. E. Nyquist KR NASA Johnson Space Center, Houston, TX, USA Acknowledgments: C.-Y. Shih, D. Bogard, J. Park Introduction and Overview

? Current status of Martian meteorite (MM) ages ? Methods, examples, and factors ? No “old” shergottites ? Comparisons to cratering chronologies ? Hartmann/Neukum ?S. Werner’s 2005 Ph. D. thesis ? Stöffler-Ryder derived curve ?Implications for meteorite source regions ? Possibilities for calibrating the cratering curve ? Possibilities for dating secondary mineralization ? Example: Nakhlite iddingsite. ?VERY preliminary Rb-Sr studies of sulfates ? Some analytical requirements for in situ age dating ? Mostly for Rb-Sr, Sm-Nd Martian and Lunar Meteorite Ages and Cratering Chronology 2 MN FH boundaries 101 EN LN EH LH EA MA LA

Lunar Meteorites Period 100 Neukum et al. (2001) Moon Martian Meteorites -1 Lunar data EN ~1%

) 10 (Stoeffler & Ryder, 2001) -2 Mars = 1.55 x Lunar data MN/LN 10-2 Autolycus Aristillus ~19% Werner (2005) H~21% Mars N(1) (km 10-3 EA ~9% MA ~5% 10-4 AAa2n ~AEC2 Werner (2005) LA ~2% 10-5 5 4 3 2 1 0 % Surface Time before Present (Ga) Area Cerberus Plains S Zunil Crater AEC2

AAa2n Elysium Mons Olympus Mons AAa1n

Werner (2005), Fig. 14.3. Geologic map from Tanaka et al. (2005) with numbered units for crater size-frequency distribution measurements by Werner. Adapted from S. Werner (Thesis, 2005) Adapted from Ph. D. Thesis of S. Werner (2005; Fig. 15.13) From S. Werner (Thesis, 2005, Fig. 14.11) Radiometric Lunar and Martian Surface Ages and Impact Chronology 5 4 3 2 1 0 101

Ka 009A881757 Dho287A 100 LAP02205NWA 032Lunar Meteorites Y86032 Neukum et al. (2001) Moon Martian Meteorites -1 Lunar data EN ~1%

) 10 (Stoeffler & Ryder, 2001) -2 Mars = 1.55 x Lunar data MN/LN 10-2 Autolycus Aristillus ~19% Werner (2005) H~21% Mars N(1) (km 10-3 EA ~9% MA ~5% Hartmann (2005): -4 AAa2n 10 ? log N = +0.1911 shallow, M ~AEC2 LA ~2% (NM/Nm)T, 2

Nyquist (2005) : Revised Martian Crater Curve 30 (= Stoeffler & Ryder (2001) Lunar x 1.55)

25 Martian Meteorites (solid symbols) NDDS melts unsampled 20 A Hesperian 15 LN/MN

10 Surface Area (Vol. %) 5 EN 0 4 3 2 1 0 Time before Present (Ga)

Percentage of Exposed Volcanics on Modern Mars in Each Epoch 30 Noachian Hesperian Amazonian 25

20 Hartmann/Ivanov

15 Neukum/Ivanov 10 Surface Area %

5 H A N 0 4 3 2 1 0 Time before Present (Ga) NWA 1460 Basaltic Shergottite Basaltic Shergottite - NWA 1460 0.714 interior fines Px2(r) 0.713 Px2a(r) T=336±15 Ma Px1(r) I(Sr)=0.708968±30 Pxf(r) 0.712 Sr 87 86 86 Opq(r) Rb/ Sr 0.711 Leach 0.0 0.2 0.4 0.6 0.8 1.0 Sr/ WR2(l)

87 1 +15 Ma 0.710 0 ?Sr WR2(r) -1 WR2 -2 -15 Ma 0.709 Plag1,2(r)

0.0 0.2 0.4 0.6 0.8 1.0 87Rb/86Sr Basaltic Shergottite - NWA 1460 0.5134 interior fines Px2a(r) 0.5132 Px1(r) T=350±16 Ma WR(r) ? =+10.6±0.5 Px2(r) 0.5130 Nd Opq(r) Nd

144 147Sm/144Nd 0.5128 0.2 0.4 0.6 Nd/ WR2 143 Leach 0.8 0.5126 WR2(l) 0.4 -16Ma 0.0 ?Nd Plag2(r) -0.4 +16Ma -0.8 0.5124 Plag(r)

0.2 0.3 0.4 0.5 0.6 147Sm/144Nd Basaltic Shergottite - NWA 1460

16000 NWA 1460 - Plag 6-98% 39Ar

12000 -Trap

Ar Age = 353±16 Ma

36 40 36 8000 ( Ar/ Ar)Tr=372±98 Ar/ 36 37 40 Ar/ Ar=0.000589

4000 Age = 334±19 Ma 40 36 ( Ar/ Ar)Tr=434±97 36Ar/37Ar=0.000456 0 0 400 800 1200 1600

39 36 Ar/ Ar-Trap 4000 Isochron Age Zagami FG-Plag 3500 = ?300 Myr

3000 40Arxs is distributed through the lattice 2500 Ar 36 2000

Ar / Larger 40Arxs (at 40 1500 intermediate temp 0-25% 1000 extractions 23-54% 54-98.5% of 39Ar ) 500 25-54% “hump” : 0 0 50 100 150 200 250 300 350 40Ar/36Ar= ?1000 39Ar / 36Ar (could be Martian atm in a shock Bogard & Park (2008) produced phase) Slide courtesy of J. Park Excess 40Ar in Zagami Mineral Separates

Phase 40Ar % total Values calculated by xs subtracting from -7 3 CG-Plag 15.7x 10 cm 32 measured 40Ar, the FG-Plag* 23.4 (17.9)x 10-7 cm3 54 amount of 40Ar* in situ, CG-Px2 10.8x 10-7 cm 3 85 assuming Zagami formation age of 170 Myr. FG-Px 2 9.2x 10-7 cm 3 86 FG-Px 1 15.3x 10-7 cm 3 89 No significant difference between CG & FG, nor between Plag & Pyx (*Second value for FG-Plag subtracts the trapped component with 40Ar/36Ar=1000.) 40Ar = ?1-2x10-6 Bogard & Park (2008) suggest xs (in cm3STP/g)

Similar 40Ar excesses are also observed in other shergottites (Bogard, Park & Garrison, 2008, submitted. Courtesy of J. Park) For Nakhlites: Common Age; No Evidence of Significant Excess 40Ar 20000 Isochron Age =1325 ±18 Myr Nakhlites 18000 R2=0.9986 MIL03346 16000 NWA-998 14000 Y-000593

12000 Nakhla Gov. Valadares 10000

Lafayette 2400 K ppm 8000 Chassigny

6000

4000

2000

0 0 0.0E+00 2.0E-05 4.0E-05 6.0E-05 8.0E-05 1.0E-04 1.2E-04 1.4E-04 1.6E-04 40 3 Total Ar cm /g Courtesy D. Bogard Common Age and 10-22 x10-7 cm3/g Magma-Derived 40Ar

5000 Shergottites Zagami

All 170 Myr Los Angeles Isochrons 4000 NWA3171

Shergotty

3000 NWA2975, 1068 Y-00097, 793605

[ K ] ppm EET79001 2000

glass 1000 High-K Plag Low-K Pyx Mid-K WR 0 0 10 20 30 40 50 60 70 80 Total 40Ar, 10-7 cm3/g Courtesy of D. Bogard Basaltic & Lherzolitic Shergottites 1.0 ? =5 ?=6 ? =4

?=8 Zagami T=700 Ma ?=6 Chen & Wasserburg (1986) Bouvier et al. (2005) Pb Borg et al. (2005)

206 0.9 ?=8 Shergotty T=173 Ma Chen & Wasserburg (1986) Pb/ ? =10 Sano et al. (2000) wtd avg.

207 Los Angeles Sh Phos Blanks Bouvier et al. (2005) (SIMS) EETA 79001 EETA LA MT Chen & Wasserburg (1986) Y793605 Sh,Za Misawa et al. (1997) Y79 0.8 0.05 0.06 0.07 0.08 0.09

4.0 Ga 173 Ma 204Pb/206Pb Shergottites

LA Zagami Mask. leach Zagami (Bouvier et al. 2005) 1.0 Shergotty

i MT 0.8 Pb)

206 95% conf. intervals Pb/ 0.6 Assimilant range 207 (

0.4 "4.0" Ga line

0.00 0.02 0.04 0.06 0.08 204 206 ( Pb/ Pb)i Shergottites 0.08 Zagami LA Chen & Wasserbug ; Borg et al

i 0.07 Shergotty Bouvier et al

Pb) 95% conf. intervals 206 ~0.064 0.06 Pb/ Assimilant range 204 (

0.05 ~0.725 Assimilant range

0.720 0.722 0.724 0.726 0.728 0.730 87 86 ( Sr/ Sr)i ~0.3 Ga ~2.6 Ga ~1.6 Ga

Spirit Opportunity

Figure 1 from Nimmo and Tanaka (2005) Ann. Rev. Earth Planet. Sci., 33, 133-161 Surface ages from Hartmann et al. (1981) Young Elysium Volcanics ~100 Ma Apollinaris Patera 3.7 to ~3.1 Ga

10 S

Gusev X Spirit 15 S ~3.6 to ~1.8 Ga

>3.7 Ga

170 E 175 E 180 E Gusev Crater with Apollinaris Patera Image and Age Ranges Courtesy of K. Tanaka

Nakhlite - MIL 03346 0.5128 T=1.36±0.03 Ga Cpx2(r) WR1,2(r) ?Nd=+15.2±0.2 Cpx1 0.5124 Cpx3 Nd 147 144 144 WR1 Sm/ Nd 0.12 0.16 0.20 Nd/ Gl Ol2

143 0.4 +30Ma 0.5120 Ol 0.0 ?Nd WR(l) Cpx2(l) -0.4 -30Ma 0.5116 0.09 0.11 0.13 0.15 0.17 0.19 0.21 147Sm/144Nd Nakhlite - Lafayette 0.708 T=1.26+0.07 Ga

ISr=0.70260+0.00014 WR(l) 0.706 Ol(r) Id1(l) Id2(l) Sr Id2(r) 86 WR2 Px(l) Sr/ WR1 Ol(l) 87 WR(r) Id1(r) 0.704 Px(r) Tidd?=~680 Ma

0.702 0.0 0.1 0.2 0.3 87Rb/86Sr

Shih et al. (1998) Kuebler et al. (2003) A study of olivine alteration to iddingsite using Raman spectroscopy. LPSC34.

“Iddingsite...a catch-all term to describe reddish alteration products of olivine...an Å-scale intergrowth of goethite and smectite (saponite)...

“Alteration conserves Fe (albeit oxidized),

but requires addition of Al and H2O and removal of Mg and Si.”

Kuebler et al. (2003), Fig. 2. Orthopyroxenite ALH84001

0.85 Silicates S6 T = 4.55+0.30 Ga

ISr = 0.6997+0.0020 0.80 Sr 86 Sr/ 87 Carbonates 0.75 T = 3.90+0.04 Ga

ISr = 0.70205+0.00013 S5 0.70 S4 0.0 0.5 1.0 1.5 2.0 2.5 3.0 87Rb/86Sr

Borg et al. (1999) The age of the carbonates in Martian Meteorite ALH84001. Science, 286, 90-94. Clark et al. (2005) Chemistry and mineralogy of outcrops at Meridiani Planum. EPSL 240, 73-94. Fig. 12 showing the modeled mineral components of outcrops at Endurance, Fram, and Eagle Craters from the APXS and MB instruments. Modeled total sulfate abundance is 35 % for SO3 = 20%. Outcrop sulfates at the Opportunity Site, Meridiani Planum (Mini-TES; Glotch et al. (2006) JGR 111, E12SO3)

Mineral “Base Model” Terr. Rb-Sr Sample Na-jarosite

NaFe3(SO4)2(OH)6 10% (5% ?) Y LNVJAR1-FP K-jarosite

KFe3(SO4)2(OH)6 (5% ?) Y GCJAR1-FP Kieserite . MgSO4 H2O 20% Y KIEDEI Anhydrite

CaSO4 10 % Gypsum . CaSO4 2H2O Y WD164A1 Terrestrial sulfate samples courtesy of R. Morris Preliminary Rb-Sr Study of Terrestrial Sulfates

• K-Jarosite – KFe3(OH)6(SO4)2 (15 mg) – GCJAR1-FP (New Mexico)

– Readily soluble in HF+HNO3

• Na-Jarosite – NaFe3(OH)6(SO4)2 (16 mg) – LNVJAR1-FP (Nevada)

– Readily soluble in HF+HNO3 . • Gypsum – CaSO4 2H2O (16 mg) – WD164A1 (Italy) – Insoluble in hot water, soluble in 1N HCl . • Kieserite – MgSO4 H2O (26 mg) – KIEDEI (Germany)

– Insoluble in room temperature H2O (15 min) – Soluble in hot H2O (1 hr) Hypothetical Sr-Isotopic Evolution in Ancient Sulfates with Terrestrial-Sample Rb/Sr ratios 0.708

Ancient alteration 0.706 T=4.56 Ga Kieserite (KIEDE1) 0.704 Sr 86 0.702 Na-Jarosite 0.8 0.9 1.0 1.1 1.2 Sr/ (LNVJAR1) 87 0.78 T=4.56 Ga 0.700 0.76 Gypsum K-Jarosite (WD164A1) (GCJAR1) 0.698 0.74

0.00 0.04 0.08 0.12 0.16 0.20 87Rb/86Sr Mauna Kea Basaltic Tephra & Jarosite 80

Fresh tephra Altered tephra 60

40

Nd (ppm) Jarosite 20

0 0 5 10 15 20 Sm (ppm) Mauna Kea Basaltic Tephra & Jarosite 0.5123 Basalt age T(Ar-Ar)=400±26 Ka Fresh Altered (Sharp et al. 1996) tephra tephra Nd

144 0.5122

Nd/ Tephra-Jarosite

143 errorchron Maximum Jarosite Age Jarosite T=230±140 Ma T=~400 Ka; ?Nd=+6.5

0.5121 0.04 0.06 0.08 0.10 0.12 0.14 147Sm/144Nd Mauna Kea Basaltic Tephra & Jarosite Maximum Jarosite Age Jarosite T=~400 Ka; I(Sr)=0.703451 0.70346

0.70344

Sr altered

86 tephra Tephra alteration 0.70342 Sr/ errorchron

87 T=5.1±1.8 Ma 0.70340 fresh tephra Basalt age T(Ar-Ar)=400±26 Ka (Sharp et al. 1996) 0.70338 0.0 0.2 0.4 0.6 0.8 87Rb/86Sr Basaltic Shergottite - NWA 1460 Bulk Rock Acid-leaching Experiment 0.5134

interior fines WR(r) 0.5132 T=354±22 Ma Acid-residues =+10.5±0.5 0.5130 ?Nd Nd

144 147Sm/144Nd 0.5128 0.2 0.4 0.6 Nd/ WR 143 0.8 +22Ma 0.5126 0.4 0.0 ?Nd WR(l) -0.4 0.5124 Acid-leachates -0.8 -22Ma

0.2 0.3 0.4 0.5 0.6 147Sm/144Nd Basaltic Shergottite - NWA 1460 Bulk Rock Acid-leaching Experiment 0.714 interior T(Min.)=336±15 Ma 0.713 fines I(Sr)=0.708968±30

0.712 Sr 86 0.711 WR Sr/ leachates T(WR)=170±36 Ma 87 I(Sr)=0.709329±61 0.710 WR 0.709 WR residues

0.0 0.2 0.4 0.6 0.8 1.0 87Rb/86Sr Martian Meteorites 0.76 Orthopyroxenite T=~4.56 Ga

0.74 Olivine-shergottites Shergottites T= ~165 Ma

Sr T=~165 Ma

86 87 86 Rb/ Sr

Sr/ 0.72 errors

87 ±10% Nakhlites ±5%

T=~1.3 Ga Sr 86 ±1% ±1‰ Sr/ errors

0.70 Depleted shergottites 87 T=327-575 Ma

0 1 2 3 4 87Rb/86Sr Martian Meteorites

147 144 0.520 Orthopyroxenite Sm/ Nd T=~4.56 Ga errors ±10% ±5% Depleted shergottites T=327-575 Ma 0.516

Nd Nakhlites

144 T=~1.3Ga Nd Nd/ 0.512 144 ±1‰ ±1% errors Nd/ 143

Shergottites 143 Olivine-shergottites 0.508 T= ~165 Ma

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 147Sm/144Nd Summary and Conclusions

? Large inherent uncertainty in cratering chronologies ? Date an Early-Mid Amazonian (~1-3 Ga) surface to calibrate. ?Gusev-like site probably OK ? Absolute dating of the Hesperian/Noachian also desirable. ?Better for “life”, “late heavy bombardment” issues. ?Meridiani-like site may be OK ? Dating aqueous activity/secondary minerals/life habitats ? Hard, even for laboratory-based geochronology. ?Isochron methods (esp. Rb-Sr) look promising ?Ar-Ar techniques also should be investigated. ? Micro-beam techniques available for a returned sample. ?SIMS: shergottite phosphates, baddeleyite; nakhlite phos. ? In Situ Dating ? Hard to impossible by traditional methods ? Best bet: redundant methods ?K-Ar with gas source mass spectrometer ?Automated chemistry lab for simple leaching, etc., with solids source mass spec (TIMS) Outcrop sulfates at the Opportunity Site, Meridiani Planum (Mini-TES; Glotch et al. (2006) JGR 111, E12SO3)

Mineral “Base Model” Terr. Rb-Sr Sample Na-jarosite

NaFe3(SO4)2(OH)6 10% (5% ?) Y LNVJAR1-FP K-jarosite

KFe3(SO4)2(OH)6 (5% ?) Y GCJAR1-FP Kieserite . MgSO4 H2O 20% Y KIEDEI Anhydrite

CaSO4 10 % Gypsum . CaSO4 2H2O Y WD164A1 Terrestrial sulfate samples courtesy of R. Morris

Mauna Kea Basaltic Tephra and Jarosite (Two End-member Mixing Model) 0.710

Marine aerosol For Sr : (contaminant) Jarosite=~75% Marine aerosol + ~25% Tephra 0.708 Sr

86 0.706

Sr/ % of Marine aerosol

87 99% in Tephra 95% 0.704 90% 80% 70% 50% 30% 10%

Jarosite Fresh Tephra (~75% aerosol) 0.702 0 200 400 600 800 1000 1200 1400 Sr (ppm) Mauna Kea Basaltic Tephra and Jarosite (Two End-member Mixing Model)

0.5124 Jarosite Fresh Tephra (~50% aerosol) 0.5122 20% 10% 60% 40% 30% 70% 0.5120 80% Nd 90% % of Aerosol

144 0.5118 in Tephra 95%

Nd/ 0.5116

143 99% 0.5114 For Nd : 0.5112 Aerosol Jarosite=~50% Marine aerosol (contaminant) + ~50% Tephra 0.5110 0 10 20 30 40 50 60 70 Nd (ppm) Nakhlite - Y000593 0.707 "Iddingsite" T=650±80 Ma Ol(l) Ol(r) 0.706 Cpx2(l) >3.95(l) WR(l) WR1 0.705 Cpx(l) Sr Ol(residues) 86 WR(r) NM(l) T=614±29 Ma Sr/ Cpx(r) >3.95(r)

87 0.704

0.703 NM(r) T=1.30±0.02 Ga Cpx2(r) I(Sr)=0.702525±27 0.702 0.0 0.1 0.2 0.3 0.4 87Rb/86Sr

Misawa et al. (2005) Antarct. Met. Res., Fig. 3 Lunar Mare Basalt Meteorite - Kalahari 009

T=4.30±0.05 Ga 0.516 ?Nd,CHUR=+0.83±0.47 Px2(r)

?Nd,HEDR=-0.04±0.47 Px1(r) 0.514 Nd WR 147 144 Sm/ Nd 144 Plag(r) 0.2 0.3

Nd/ WR(l) 1 0.512 +52Ma 143 Leach 0 ?Nd HEDR 0.510 -1 -52Ma CHUR

0.15 0.20 0.25 0.30 147Sm/144Nd Crystallization and Ejection Ages of Martian Meteorites Compared to Martian Epochs with Hartmann/Neukum (2001) Ages

5 Lyon Hypothesis H/N A84 EA (Ga)

1 MA Nakhlites & Chassigny

0.5 DaG, Y98 Dho NWA 1195 480/1460, QUE LA Local Stratigraphy? 1068 Crystallization Age A77, LEW, Y79 EET BU PE 0.1 Zag, She, LA, 856

0.5 1 5 10 20 Ejection Age (Ma)

Basaltic shergottites Dunite (Chassigny) Lherzolitic shergottites Orthopyroxenite Clinopyroxenites (Nakhlites) Hypothetical Sr-Isotopic Evolution in Sulfates with Terrestrial-Sample Rb/Sr ratios 0.7229 Basalt crystallization Recent alteration T=180 Ma T=10±1.4 Ma

0.7228

Sr K-Jarosite 86 Sr/

87 WR 0.7227 Kieserite Na-Jarosite Gypsum 0.7226 0.0 0.2 0.4 0.6 0.8 1.0 1.2 87Rb/86Sr