[X] My Assistant

[aldo12xu]

With the Spirit rover sitting in one spot, it's given me a chance to come up with an updated summary of the various Gusev and Columbia Hills rock types, geochemistry and latest geological interpretations. There have been several good papers but there hasn't been one comprehensive paper to put everything together (that I know of). And the one key component to interpreting the data that is still missing is a detailed structural model of the Columbia Hills. Nevertheless, I've tried my best to make sense of all the various information out there.

There are still a number of uncertainties and inconsistencies -- which are open to discussion here -- but in general terms I think this is the stratigraphic sequence we're looking at, with various alteration processes overprinting this stratigraphy:

ADIRONDACK basaltic flows related to the volcano Appollinaris Patera, 300 km to the north
BACKSTAY & IRVINE late stage mafic intrusive dikes cut through all Columbia Hills units
HOME PLATE maar type volcanism emplaced through Columbia Hills, interacting with groundwater
DESCARTES, CLOVIS & WATCHTOWER meteorite impact ejecta deposits mixing different rock types
INDEPENDENCE & WOOLY PATCH phyllosilicates derived from chemical weathering of volcaniclastics
WISHSTONE tuff or pyroclastic deposit (impact origin not fully discounted*)
PEACE sandstone produced by wind erosion of older ultramafic units
SEMINOLE mafic to ultramafic intrusive or extrusive rocks

The link to the summary is on my homepage.

[climber]

Have you seen this on MER website?
New Class of Igneous Rocks :
http://marsrovers.jpl.nasa.gov/gallery/pre.../20060823a.html
I'm not able to understand this but, I'm curious to get an explanation regarding the part of the graph called "Martian meteorites". I assume this show meteorites found on Earth and believed to come from Mars. Does it simply means that those metorites doesn't come from Gusev?

[tfisher]

An interesting link directly relating to the new geo-chemistry chart mentioned in the previous post:
in this Lunar and Planetary
Science paper the authors discuss earthly analogues of the minerals found. They include a slightly-less-up-to-date Total Alkali-Silica diagram, which shows how the newer samples discovered by Spirit in the Columbia hills have expanded the bounds of what has been observed...



edit: I can't get the link to be clickable. Sorry, I don't know what I'm doing wrong. Lets try one more time: link