[X] My Assistant

[Guest_RGClark_*]

Last year I made a plea for Spirit to examine the dark material in Bonneville crater:

From: rgregorycl...@yahoo.com (Robert Clark)
Date: 20 Mar 2004 05:50:12 -0800
Subject: Mystery material in the Bonneville crater on Mars.
Newsgroups: sci.astro, alt.sci.planetary, sci.geo.geology, sci.geo.mineralogy
http://groups.google.com/group/sci.geo.geo...21ac267d592d633

Spirit was not commanded to enter the crater for fear of it being trapped by the craters steep slopes.
However, Edstrick noted that the dark sands in El Dorado resembles the dark material in Bonneville:

Non color calibrated image.

(Note: in uncalibrated images this material appears blue, but without calibration data all that can be said is that it is darker than the surrounding terrain.)

Then we may have another chance for determinining the make up of this dark material. I argue that this material may resolve one of the key questions on the mineralogy of Mars: what is the make up of the wide spread dark material seen on Mars, termed Surface Type 2 rock by Mars Global Surveyor scientists.
As I discuss in the sci.astro post, two explanations have been offered: one that it is andesitic rock, the other that it is liquid water altered basalt. Both the andesitic and weathered basalt explanations have important implications for the geologic past of Mars - the andesitic, suggesting tectonic plates may have operated on Mars, and the weathered basalt, suggesting liquid water oceans may have occurred on Mars.



Bob Clark