WILLIAM K. HARTMANN
PLANETARY SCIENCE INSTITUTE"RECENT GEOLOGICAL ACTIVITY ON MARS"
Evidence continues to accumulate that Mars is geologically active. Dr.
Hartmann, a member of the Mars Global Surveyor team, pioneered one method
of dating Martian features -- counting numbers of impact craters
superimposed on them. Hartmann and his group sought young lava flows and
derive ages as young as 10 Myr to 100 Myr. Independent isotopic dating of
19 Martian meteorites reveals lavas from different sites, dating 170 to
575 Myr old, plus older rocks. Some of these show water flow activity
within the last 670 Myr. Martian erosion gullies look even younger, and
similar water erosion features have been found in Iceland, Greenland, and
Canada. Young aquifers have implication for life on Mars.