Help Shape the Future of Space Exploration

Join The Planetary Society Now  arrow.png

Join our eNewsletter for updates & action alerts

    Please leave this field empty
Blogs

Ryan Anderson

Is Eberswalde Really a Smoking Gun?

Posted by Ryan Anderson

03-08-2010 19:20 CDT

Topics: Mars, Curiosity (Mars Science Laboratory)

This article originally appeared on Ryan Anderson's "The Martian Chronicles" blog and is reposted here with permission.

The other day in Mars journal club, we took a look at a paper about the "fan" in Eberswalde crater. You may recognize this name: It is one of the four finalist landing sites for MSL. The site was chosen because at the western end of the crater, there is a feature that most Mars scientists consider to be a delta, formed when sediment transported by rivers encountered standing water and settled out.

Eberswalde Delta

NASA / JPL-Caltech / MSSS

Eberswalde Delta

The paper we looked at considered an alternative to the delta hypothesis. Instead, Jerolmack et al. proposed that the fan could be an alluvial fan, formed by river channels that "avulsed" back and forth to form a gradually sloping fan. "Avulsed" means that the river abruptly changes its course. When you average out over lots of avulsions, you get a broad, shallow cone of material deposited: an alluvial fan.

Jerolmack used a computer model of this style of fan formation and fit it to the slope of the Eberswalde feature's surface. They found that, if the Eberswalde fan is actually alluvial, it would have formerly extended about 40 km out into the crater, and that it could have formed extremely rapidly: in tens to hundreds of years, and with no need for a standing body of water.

That's a much different story than the more popular one: that the Eberswalde fan is a delta that formed over many thousands of years in a lake. Which scenario is correct? I don't know. It may not be possible to know from orbit. That's part of why Eberswalde is a candidate MSL landing site: If our "smoking gun" evidence of a lake on Mars turns out to be an alluvial fan deposited in 50 years, then that certainly has an influence on the question of the habitability of Mars as a whole! Of course, everyone hopes that it is truly a delta, in which case it would have been favorable for preserving organic biomarkers and would record a lot of information about the martian environment.

There's only one way to know for sure: land there!

ResearchBlogging.orgJerolmack, D. (2004). A minimum time for the formation of Holden Northeast fan, Mars Geophysical Research Letters, 31 (21) DOI: 10.1029/2004GL021326

 
See other posts from August 2010

 

Or read more blog entries about: Mars, Curiosity (Mars Science Laboratory)

Comments:

Leave a Comment:

You must be logged in to submit a comment. Log in now.
Facebook Twitter Email RSS AddThis

Blog Search

Essential Advocacy

Our Advocacy Program provides each Society member a voice in the process.

Funding is critical. The more we have, the more effective we can be, translating into more missions, more science, and more exploration.

Donate

Featured Images

NGC 4100
The Flaming Star Nebula (IC 405)
LDN 604 and GGD 30
Schiaparelli backshell and parachute landing location from HiRISE in color
More Images

Featured Video

The Planetary Post - Carl Sagan's Pale Blue Dot

Watch Now

Space in Images

Pretty pictures and
awe-inspiring science.

See More

Join The Planetary Society

Let’s explore the cosmos together!

Become a Member

Connect With Us

Facebook, Twitter, YouTube and more…
Continue the conversation with our online community!