Friday, February 25, 2011

Your Mars Lesson of the Week

Posted By on Fri, Feb 25, 2011 at 4:45 PM

The UA Lunar and Planetary Lab's Alfred McEwen talks about a HiRISE photo from Mars:

Some of the largest landslides known in the Solar System have happened on Mars. These are interesting phenomena, but they also sometimes produce excellent exposures of the bedrock geology, in cross-sectional views. The purpose of this image was to view bedrock exposures at a deep level in Valles Marineris.

We have only a vague idea how old these rocks are. Crater counts date landscapes, and clearly this is a young landscape with very few impact craters due to the continual mass wasting (landslides) of the steep slopes. The rocks are much older—probably older than the plateaus surrounding Valles Marineris (2 to 3 billion years based on the large craters), unless these are intrusive rocks emplaced later from migrating magma. We need radiometric age dating, either on Mars or from returned samples, to measure the age of igneous (volcanic or plutonic) rock layers within the strata.

The age of sedimentary layers such as river or lake deposits can be bracketed by the ages of overlying and underlying igneous layers. Not knowing the absolute ages of bedrock units on Mars is a huge limitation to our understanding of the geologic history.

Lots more here.

Comments

Subscribe to this thread:

Add a comment

Previously in the Range

More by Jim Nintzel

  • Editor's Note

    Smoke Signals
    • Apr 19, 2018
  • The Skinny

    Downtown Tucson scored a big win last week when Gov. Doug Ducey signed legislation extending the life of the Rio Nuevo district for an extra decade.
    • Apr 12, 2018
  • Editor's Note

    Get Your Fest On
    • Apr 12, 2018
  • More »
Today | Sun | Mon | Tue | Wed | Thu | Fri
8th Annual Comedy for Charity: Laugh ‘til It Hurts

8th Annual Comedy for Charity: Laugh ‘til It Hurts @ Fox Tucson Theatre

Sun., April 22, 6-8:15 p.m.

All of today's events | Staff Picks

Staff Pick

Free Mozart and Beethoven Concert

Members of True Concord are joined by pianist Stephen Carlson for quintets by Mozart and Beethoven in… More

@ Dove of Peace Lutheran Church Sun., April 22, 2-3:30 p.m. 665 W. Roller Coaster Road.

» More Picks

Submit an Event Listing

Popular Content

  1. Antigone Books To Be Sold to Three Employees (If They Can Raise Some More Cash) (The Range: The Tucson Weekly's Daily Dispatch)
  2. The Weekly List: 17 Things To Do In Tucson This Week (The Range: The Tucson Weekly's Daily Dispatch)
  3. The Strike Is On: Arizona Teachers Prepared for Walkout Next Week (The Range: The Tucson Weekly's Daily Dispatch)
  4. Record Store Day Becomes Record Store Week at Zia (The Range: The Tucson Weekly's Daily Dispatch)
  5. Interview with a Robot (The Range: The Tucson Weekly's Daily Dispatch)

© 2018 Tucson Weekly | 7225 Mona Lisa Rd. Ste. 125, Tucson AZ 85741 | (520) 797-4384 | Powered by Foundation