• Site Map

    All the web pages on the conference website







My Goldschmidt

Role functions

Abstract Details

(2020) Rhyolitic (Micrographic Granite) Igneous Clasts from Ancient Mars in the Martian Meteorite Northwest Africa 8171

Lindner M, Schmitt A, Krot A & Brenker F


Sorry, the PDF cannot be displayed on your browser.

Download abstract

The author has not provided any additional details.

01a: Room 1, Tuesday 23rd June 07:36 - 07:39

Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.

Submitted by Craig O'Neill on Tuesday 23rd June 06:28
Amazing clast. Most of Mars's volcanos are shield, and satellite spectroscopy suggest a (mostly) basalt surface (I generalise). Where then might the surface expression of felsic volcanism be? Do you envisage this was originally extrusive? And if so, are there surface indicators (stratovolcanos, spectroscopically identifiable rhyolite)? Or do you envisage this is very small volume?
Hi, thanks. Sorry for the only quick and certainly not sufficent answer during the Q/A session. I cannot say whether these igenous clast are representants of a larger silica rich body. There are rhyolitic melt pockets within the shergottite NWA 6963 (eg. Gross & Filiberto, 2014) which do show similar texture and composition. So these clasts might be parts of a rock represented by this meteorite. However if the silica grains are related to the clasts, which might be indicated by the fact that they are as well only present within this PBC-01 lithology like clast8 and clast9, this could be an indicator that there actually was a more silica rich lithology present and maybe also as a larger volume, since the number of silica grains is relatively high (we found 13 between 40-200µm and numerous smaller ones dispersed thoughout the PBC-01 lithology). So where might the surface expression of this then be? I can again only speculate (I'm sorry) and would say that erosional products of this lithology could be present within the Martian regolith. I think the sub-rounded shapes of the silica grains points to the direction that these were present within the regolith as erosional products of their original lithology, rather than still part of it, and were then incorporated into this PBC-01 lithology during an impact. PBC-01 is very similar to the clast laden impact melt rock described by Hewins et al. in 2017. I'm not sure though if there already exists sufficent spectrometry data from Mars orbiters to resolve this still rather small component of high silica clasts within the Martian regolith. Wittmann et al. in 2015 report a possible ejection site of the paired Meteorite NWA 7475 at the northen edge of the southern highlands based on (amongst other things) Th and Fe concentrations of the meteorite compared the concentrations of the Martian surface measured with the Mars Odyssey Gamma Ray Spectrometer. The southern highlands are more geologically diverse and I think in searching for this signal I would start there. However to find out more about the formation of these clasts (residual melt pockets in gabbroic rock, differentiated impact melt or maybe extrusive volcanism), more analysis is certainly needed and we are right now working on trace element analysis of clast8 to get more information in this aspect. I hope I could answer your question better this time and please don't hesitate to ask further questions. Thanks! Miles

Sign in to ask a question.

Goldschmidt® is a registered trademark of the Geochemical Society and of the European Association of Geochemistry

Website managed and hosted by White Iron Conferences on behalf of the international geochemical community