IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Spheres At Spirit Site Too?
Guest_Sunspot_*
post Feb 12 2004, 12:43 PM
Post #1





Guests






Sol 39 microscopic imager:

http://marsrovers.jpl.nasa.gov/gallery/all...00P2943M2M1.JPG

Wonder if they have a similar origin.
Go to the top of the page
 
+Quote Post
jmknapp
post Feb 12 2004, 10:25 PM
Post #2


Senior Member
****

Group: Members
Posts: 1465
Joined: 9-February 04
From: Columbus OH USA
Member No.: 13



Here's a bit of a closeup:



They look a bit more flattened in general that the ones at Meridiani. but definitely still have the look of accretionary lapilli. Those are the little mud/ash balls that precipitate out of volcanic plumes. When they land they may get flattened and they also land on top of each other. You can see the dents here and there where one landed on another.

It's interesting that on Monday Dr. Squyres said that there were three theories for the opportunity spherules, lapilli, soldified magme/ejecta or concretions. He said that the lapilli idea was "fading fast."

There was not a word said today about any more progress in nailing that down (Squyres wasn't on the panel and he seems to be the only one willing to run down competing theories and scoring them.)

However an interview yesterday with Ronald Greeley, Ph.D., Regents Prof. of Geology, Arizona State University Dept. of Geological Sciences, and one of the 7 Chairs of the Science Operations Working Group (SOWG) for Spirit and Opportunity was a bit more illuminating. When asked about the spherules, he replied:

"The general consensus seems to be centering around two possibilities:

"* First, that they are what are called 'accretionary lapillae' that is a volcanic feature that forms in certain kinds of eruptions in which material is added to a small nucleus like a little dust grain and these form these spherule masses.

"* Secondly, they could be some kind of precipitate perhaps from water. In additional findings, there are some minerals that have been identified in the infrared that would suggest the presence of water since they form in water. In particular, if this is a volcanic terrain that we are looking at, the presence of these minerals might suggest this was a hydrothermal area."

Link to interview: Earthfiles.com

So isn't that interesting? It seems that the accretionary lapilli are back at the top, and the other two candidate theories entioned by Squyres are nowhere to be seen, in favor of a new theory about precipitates.

This is based in part on the finding of high sulphur content in the outcrop.

So pass the word, accretionary lapilli are back.


--------------------
Go to the top of the page
 
+Quote Post
jmknapp
post Feb 12 2004, 10:31 PM
Post #3


Senior Member
****

Group: Members
Posts: 1465
Joined: 9-February 04
From: Columbus OH USA
Member No.: 13



Oops, messed up the link to the interview:

Feb. 11, 2004

Ronald Greeley, Ph.D., Regents Prof. of Geology, Arizona State University Dept. of Geological Sciences, and one of the 7 Chairs of the Science Operations Working Group (SOWG) for Spirit and Opportunity, Tempe, Arizona

Part 1

Part 2

He talks about the spherules in Part 2.


--------------------
Go to the top of the page
 
+Quote Post

Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 2nd December 2020 - 11:59 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.