new news about Haematite says all of a sudden that it may not be the "smoking gun" for water, after all:-

First data point - when crushed by the airbags, the haematite signature of the blue-grey granules disappears into red dust, like fairies in sunlight. (or is that Vampires?)

page 1
Page 2 has the important stuff

Second, a new article is about to throw a wrench into the water story...

Subject: A Possible Surprise for MER: Hematite Coatings Instead of Coarse Hematite

Laurel Kirkland has sent the following email to the science
community:

"The attached Geophysical Research Letters preprint (accepted Jan
23rd) shows that the anticipated "coarse hematite" ('gray hematite') at Sinus Meridiani may instead be fine, consolidated hematite. If so, then the longstanding 'coarse-only' interpretation is incorrect, and the result has interesting implications. For example, the hematite could differ in consolidation rather than abundance or particle size. The submission was accepted on Jan 23rd, prior to the rover 'Opportunity' landing.

"The TES-ASU team has argued that TES spectra of Sinus Meridiani are consistent only with coarse hematite (>5-10 micron particles). On the other hand, the Aerospace/LPI remote sensing team has argued since 2000 that both the TES and 1971 IRIS spectra exhibit bands that are too narrow to match coarse hematite. The Aerospace/LPI team then demonstrated that fine hematite matches the observations when the particles are closer than ~wavelength of the light. This is called 'fine-intimate' hematite. For example, a thin coating (~5- 10 microns thick) and small fractional exposure (<5%) of fine- intimate hematite could cause the observed signatures. Other fine- intimate versions of hematite can also match, e.g., ferricrete, clumped hematite. Whether rover instruments can definitively discriminate between the different forms remains to be determined.

"If MiniTES confirms the narrow bands observed by TES and IRIS, then the TES-ASU team's longstanding "coarse-only" interpretation will likely no longer stand. The identification of the exposure remains important; however the reasons may differ from those that built on the "coarse-only" interpretation. It is important to understand potential fine-intimate hematite options in order to test what is indeed present and to understand the implications. For example, the hematite could have formed as it does elsewhere on Mars, but consolidation may be what is unique to the site. Such potential options could be exciting, but remain to be explored. The physical explanations of spectral behavior in the GRL paper provide the foundation to initiate such studies methodically. The Aerospace/LPI team was the first to identify the mismatch of coarse hematite to TES spectra, to demonstrate the match of fine-intimate hematite, and to explain the physics of the spectral behavior. Further information is in the GRL paper and will also be added to the web site below."

A Possible Surprise for the 2003 Mars Rover: Hematite Coatings Instead of Coarse Hematite http://www.lpi.usra.edu/science/kirkland/

- Nick

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Nick Hoffman Mars Specialist

White Mars Research Programme
School of Earth Sciences
University of Melbourne
Parkville, Australia 3010

Mobile: 0438 397 366

http://www.whitemars.com
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