[X] My Assistant

[aldo12xu]

Hi folks I just summarized some of the abstracts I read on the alteration and chemistry of the rocks on the Gusev plains and Columbia Hills. The most interesting thing I found was that the rocks at West Spur seem to have gone through a different alteration process than those higher up in the Columbia Hills.

So check it out and feel free to correct me on any points.

Cheers,
Aldo.

[Phil Stooke]

Following up on this thread and also The Other Doug's last post on the Jibsheet thread, on the same subject...

The outcrop at Larry's Lookout/Methuselah appears to dip to the north (or a bit to the northwest), and to strike east-west (or a bit to the southwest-northeast) - let's say a strike azimuth of about 60 degrees (from north). This suggests that the younger rocks, upper levels in the column, are to the north - Clark Hill etc. - and the older rocks are to the south, including the summit of Husband hill, and certainly in the Inner Basin. If the rocks were horizontal the summit would be younger, but the apparent dip we see in this current location makes the summit look older to me. Anyway, it's amazing to think we are actually exploring stratigraphy in the field like this.

Incidentally the latest cPROTO image, the one showing rover tracks all the way to West Spur, shows very nicely how the strike of some of these layers can be traced across Husband Hill and West Spur. I think we will eventually have an excellent idea of the stratigraphy from a combination of ground analysis and orbital mapping.

Phil

[dvandorn]

Following up on this thread and also The Other Doug's last post on the Jibsheet thread, on the same subject...

The outcrop at Larry's Lookout/Methuselah appears to dip to the north (or a bit to the northwest), and to strike east-west (or a bit to the southwest-northeast) - let's say a strike azimuth of about 60 degrees (from north).  This suggests that the younger rocks, upper levels in the column, are to the north - Clark Hill etc. - and the older rocks are to the south, including the summit of Husband hill, and certainly in the Inner Basin.  If the rocks were horizontal the summit would be younger, but the apparent dip we see in this current location makes the summit look older to me.  Anyway, it's amazing to think we are actually exploring stratigraphy in the field like this. 

Incidentally the latest cPROTO image, the one showing rover tracks all the way to West Spur, shows very nicely how the strike of some of these layers can be traced across Husband Hill and West Spur.  I think we will eventually have an excellent idea of the stratigraphy from a combination of ground analysis and orbital mapping.

Phil

I see what you mean about the dip vs. the strike. Well, I have a hard time positioning myself when looking at the surface images, in re direction.

So, the hills may have been uplifted from bedrock that already had a dip, eh? Curiouser and curiouser...

-the other Doug