Chromite chemistry in SNC meteorites

We present the results of new EPMA studies of chromite in primitive basaltic shergottites (SAU005, EETA7001A, DAG476) and ALH84001 and Chassigny. Chromite grains from basic and ultrabasic rocks are sensitive indicators of melt compositions and the Fe3+-Cr-Al compositions of the cores can help to distinguish between partial melting and crystal-melt fractionation histories in the SNC 30 Fe3+ Chromite grains parent melts

Carbon reservoirs on Mars: Constraints from Martian meteorites

We have measured the abundance and stable isotopic composition of magmatic carbon extracted from a suite of shergottites. The results confirm previous findings that primordial carbon on Mars is isotopically lighter than that of the Earth

The distribution of asteroids: evidence from Antarctic micrometeorites

The relative abundances of types amongst 550 AMMs are reported. These suggest that C-type asteroids vary from petrologic type 1 to 3.2 and that the majority of S-type asteroids are chondrule-rich

UV and Visible Wavelength Reflectance Spectroscopy of Aerogel and of Stardust Grains

A new UV and visible reflectance microspectroscopy technique has been applied to cometary samples from the Stardust mission. The results have been compared with terrestrial minerals and aerogel

X-Ray Microtomography of A Sulphide Rich Pallasite

The application of X-ray microtomography to the sulphide rich main group pallasite Hambleton is dicussed as an attempt to further understand pallasite genesis. X-ray microtomography is an under utilized technique for the study of diverse samples such as pallasites. The three-dimensional textures observed in Hambleton may be explained by introduction of a large sulphide volume under pressure into a metal-olivine mixture with metal approaching solidus temperature

WatSen: searching for clues for water (and life) on Mars

There is plenty of evidence for fluid on Mars: large-scale (planet-wide) features have been captured over four decades by a procession of orbiting satellites equipped with cameras with increasingly higher spatial resolutions. Imagery of the surface shows channels, valleys, ice-caps, etc. Small-scale, more local evidence for fluid has come from images obtained by rovers on the Martian surface. Images that water produced many of the features are supported by spectroscopic measurements (again both planet-wide and local) over a range of wavelengths, which show the presence of minerals generally only produced in the presence of water (haemetite, jarosite, etc.). Results from meteorites continue this picture of fluid activity taking place over significant periods of Mars' history. Despite all these indicators of water, direct detection of water has never been performed. We have reviewed the evidence for water on Mars' surface, and have described WatSen, a combined humidity sensor and infrared IR detector, which can be employed to search for water at and below Mars' surface. WatSen is designed to be part of the suite of instruments on the mole that will be deployed as part of the Geophysics and Environment Package on ExoMars. The objectives of the package are as follows: (i) to detect water within Martian soil by measuring humidity and IR spectral characteristics of the substrate at surface and at depth; (ii) to determine the mineralogy and mineral chemistry of surface soils (this measurement will provide the mineralogical context for the elemental results that come from other instruments mounted on the landing platform); (iii) to determine how mineralogy changes with depth. The utility of WatSen is that it will not only detect the presence of water, but will also be able to record which minerals are present and their chemistry; it is also sensitive to many organic species. WatSen is a new instrument concept specifically designed to search for clues of the presence of water, and to look for evidence of life on Mars

Exploring Mars with Returned Samples

The international Mars Exploration community has been planning to return samples from Mars for many years; the next decade should see the plans becoming a reality. Mars Sample Return (MSR) requires a series of missions, first to collect the samples, then to return them to Earth, whilst preventing the contamination of both Earth and Mars. The first mission in the campaign, Mars 2020, will land at Jezero Crater in early 2021; samples should return to Earth sometime after 2032. The information to be derived from analysis of martian samples in terrestrial laboratories equipped with state-of-the-art instrumentation is more than recompense for the difficulties of the MSR campaign. Results from analyses of returned samples will enable increased understanding of martian geological (and possibly biological) evolution. They will facilitate preparations for human exploration of Mars and by providing a second set of absolute ages for a planetary surface will validate (or otherwise) application of the lunar crater-age scale throughout the Solar System

Microbial D/H fractionation in extraterrestrial materials: application to micrometeorites and Mars

High D/H terrestrial alteration of micrometeorites is described and suggested to be a result of microbial isotopic fractionation by methanogens. Applications to other planetary materials, including martian meteorites, are also considered