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RE: Microbially induced sedimentary structures
A lot of the desire to find evidence of life on Mars (past or present) is
encouraging people to take non-parsimonious positions.
Among other things: what is the lithology of figure 5? Because if it is basalt
(like most of Mars' surface), mere similarity of appearance to a microbialite
Thomas R. Holtz, Jr.
Email: firstname.lastname@example.org Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Faculty Director, Science & Global Change Program, College Park Scholars
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA
> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of
> Erik Boehm
> Sent: Monday, January 05, 2015 10:37 AM
> To: email@example.com
> Subject: Microbially induced sedimentary structures
> So, its not dinosaurs, but it is paleontology... so I hope its fine for this
> mailing list:
> Recently I was in a forum discussion related to microbially induced
> sedimentary structures - specifically, how easy they are to identify,
> and how common they are in pre-cambrian sedimentary rock.
> I was under the impression that before motile multicellular organisms were
> around to break up microbial matts, that they covered the
> earth pretty much anywhere it was wet, and furthermore that pre-cambrain
> rocks often preserved this (such as the "elephant skin
> texture" often seen around the multicellular ediacaran biota).
> The ultimate focus of this discussion, however, was about Gale crater and
> Mars. There are many many many examples of layered
> sedimentary deposits visible in the photos from the Curiosity rover... none
> of which looked to me to even suggest that there were
> ever biofilms there.
> However, just now, a paper came out:
> Hypothesis Article
> "Ancient Sedimentary Structures in the <3.7Ga Gillespie Lake Member, Mars,
> That Resemble Macroscopic Morphology, Spatial
> Associations, and Temporal Succession in Terrestrial Microbialites"
> And I must say, most of the pictures are unconvincing to me, However, their
> figure 6 did pique my interest (
> http://www.astrobio.net/wp-content/uploads/2015/01/fig5.jpg - it says fig 5
> on the website that hosts it, but its fig6 in the paper) but
> I'm far from educated about what to look for (perhaps something like this is
> too optimistic:
> I was wondering if anyone here would be better able to evaluate the claims,
> and perhaps answer my above questions about the
> prevalence of pre-cambrian MISS fossils.