MarsYuk Yung3-14-05

Earth: • 13,000 km diameter• 150 million km from sun• 365 days in year• 24 hours in day• -88 deg C to +58 deg C temp range• 1000 mb surface pressure• 78% nitrogen, 21% oxygen

Mars: • 7,000 km diameter• 1.5 AU from sun• 687 Earth-day year• 24 hour, 37 minute sol (Mars day)• -127 deg C to 17 deg C temp range• 7 mb surface pressure• 95% carbon dioxide atmosphere

Number Density (cm-3)

Alt

itud

e (K

m)

Candor Chasma,Valles Marineris MGS PhotographQaidam Basin, China SRTM Shaded Relief

Mars MGS photograph; 43.2°N Lat, 90.6°W Long, in Tempe Terra

Afar Triangle, Ethiopia SRTM Shaded Relief

Martian Crater on Elysium Planitia MGS Photograph

Bosumtwi Crater, Ghana, Africa SRTM shaded relief

Gusev Crater, MarsCerro Armazones, Chile

Meridiani PlanumSan Gabriel Mountains

MSG MOC Image of “delta”system within Holden Crater on Mars (Malin et al, Science 2003)

Lena Delta in Siberia (NASA Scientific Data Purchase/Landsat 7)

A Brief History of ALH84001• 4.5 Gy ago: Igneous rock (orthopyroxenite)

which accumulated in a magma chamber on Mars. Oldest known rock from ANY planet!

• From 4.5 – 4.0 Gy: Suffered several shocks, probably from asteroid or comet impacts, formed mm-thick, cataclastic “granular bands” at high temperature.

• ~4.0 Gy ago: Major shock event brecciated it, rotated fragments, but did not heat it.

A Brief History of ALH84001, cont’d

• ~4.0 Gy ago: Carbonate blebs formed in cracks by low-T precipitation events. (Aqueous, followed by at least 1 shock.)

• 15 Myr ago: Blasted off of Mars into space by another impact

• ~11,000 years ago: After wandering through space, landed on Antarctic Ice sheet.

• ~500 years ago, exposed at surface in Allan Hills.

Was this Martian ever alive??!!

So what do the magnetite crystals in ALH84001 actually look like?

(Thomas-Keprta K.L., Bazylinski D.A., Kirschvink J.L., Clemett S.J., McKay D.S., Wentworth S.J., Vali H., Gibson E.K., Jr., and Romanek, C.S. Elongated Prismatic Magnetite Crystals in ALH84001

Carbonate Globules: Potential Martian Magnetofossils. Geochimica Cosmochimica Acta 64 (23), 4049-4081, 2000)

€

N2++e→ N+N

O2++e→ O+O

E(0) = 2.5 ev or 7km/s

Acknowledgements

• NASA

• NSF

• JPL

• Diane Michelangeli

• Chris Parkinson

• Yung’s Caltech Research group