Kite snowmelt hypothesis, a different way to form sedimentary rocks Options

[ngunn]

Mars discussion is a bit thin at the moment due to the conjunction but I could not let this pass without thanking Emily for yet another superb article elucidating a highly complex topic.

http://www.planetary.org/blogs/emily-lakda...hypothesis.html

The idea that the last liquid water on an increasingly airless Mars would have worked its geological magic under a covering of snow makes a lot of sense.

[mcaplinger]

The idea that the last liquid water on an increasingly airless Mars would have worked its geological magic under a covering of snow makes a lot of sense.

The paper is well worth reading, but as it says in section 6.2, it really doesn't address the valley networks and alluvial fans. (It tries, but doesn't completely succeed to my taste.)

As a general rule, explaining Earthlike morphology with non-Earthlike processes needs a high level of motivation. ("If it looks like a duck", etc.)
IMHO, section 1 oversells that motivation in the case of early Mars, though I need to read Haberle 1998, which I hadn't recalled was so definitive. But as a jumping-off point for discussion, the paper is very good.

[elakdawalla]

The paper is well worth reading, but as it says in section 6.2, it really doesn't address the valley networks and alluvial fans. (It tries, but doesn't completely succeed to my taste.)

Mike, one question that I had about this paper was that it takes as fact the notion that most of the observed sedimentary rocks postdate the valley networks, so that it makes sense to talk about different climates prevailing during valley network formation time and the time during which the sed rocks were getting deposited. (I guess the sediments deposited by valley network formation are either obscured or destroyed, in this scenario.) But now I'm reading the Brian Hynek stuff, which states that although valley networks formed on the oldest terrain, that if you age-date the largest networks you find they all seemed to form in late Noachian or early Hesperian. So I guess I'm not sure of the chronology. If valley networks formed only at the end of the Noachian and into the Hesperian, are they coeval with or are they older than the layered clays and sulfates that Kite was trying to explain?