Organic indicators of alteration in the CR chondrites

A study of the organic components in the CR chondrite macromolecule in order to assess the role of pre-terrestrial alteration on the organic inventory

Analysis of Tagish Lake macromolecular organic material

Macromolecular material is, by far, the major organic component of meteorites. Flash pyrolysis GCMS has been used to investigate this organic component in Tagish Lake. It is more condensed, less susbtituted than Murchson

Hydrogen isotopic composition of the Tagish Lake meteorite: comparison with other carbonaceous chondrites

A study into the hydrogen isotopic characteristics of whole rock samples of carbonaceous chondrites and their comparison with a whole rock sample of the Tagish Lake meteorite

Identification of Trace Organic Components in the CR Chondrites by 4D TOFMS

This paper reports preliminary results of a 4D TOFMS study of CR chondrite organic material, highlighting the low-level organic species that may further reveal the complexity of parent body modification of interstellar precursors

The association between organic matter and clay minerals in carbonaceous chondrites

There is an established relationship between organic matter content and aqueous alteration processes [1,2]. However, the relationship between meteoritic organic matter and individual aqueously generated mineral matrix phases is poorly understood. Meteoritic organic matter is primarily composed of C, H and N and therefore their bulk abundances in chondrites are strongly controlled by the organic matter content. Mössbauer Spectroscopy can characterise the ferric iron bearing matrix minerals associated with aqueous alteration, such as Fe- bearing clays and magnetite. A combination of these two parameters may indicate the presence of any organic-mineral interactions

Mars simulated exposure and the characteristic Raman biosignatures of amino acids and halophilic microbes

Though Raman bands of α-amino acids (AA) are well documented, often only the strongest intensity bands are quoted as identifiers (e.g. Jenkins et al., 2005; De Gelder et al., 2007; Zhu et al., 2011). Unknown regolith mixtures on Mars-sampling missions could obscure these bands. Here the case is made for determining, via a statistical method, sets of characteristic bands to be used as identifiers, independent of band intensity or number of bands (Rolfe et al., 2016). AA have upwards of 25 potentially identifying bands and this method defines sets of 10–19 bands per AA. Examination of AA-doped Mars-like basalt resulted in a maximum of eight bands being identified, as some characteristic bands were obscured by mineral bands, including the strongest intensity band in some cases. This proved the need for characteristic bands to be defined, enabling successful identification of AA. The ESA ExoMars Rover mission will crush and then pass the sample to the Raman Laser Spectrometer. We crushed a Mars-like basalt to a similar grain size expected to be created by the rover. Our samples were doped with 1 % (by weight) AA samples, resulting in no detection of AA, because of loss of original spatial context and spaces between the grains. We recommend that Raman spectroscopy on future missions should be conducted before the sample is crushed. Halite-entombed halophilic microbes, known to survive being entombed, were exposed to Mars-like surface (including temperature, pressure, atmospheric composition and UV) and freeze-thaw cycle (plus pressure and atmospheric composition) conditions. This test on the survival of the microbes showed that survival rates quickly deteriorated in surface conditions, but freeze-thaw cycle samples had well preserved Raman biosignatures, indicating that similar signatures could be detectable on Mars if similar life persists in evaporitic material or brines today

Development of visualisation methodology for organic materials contained within carbonaceous chondrites

The development of methodology for the derivatisation of the organic components of carbonaceous chondrites is described. This methodology will be used to determine the location of organic materials, in situ, and at high resolution