Raman Spectroscopic Analysis of Geological and Biogeological Specimens of Relevance to the ExoMars Mission

H.G.M.E., I.H., and R.I. acknowledge the support of the STFC Research Council in the UK ExoMars programme. J.J. and P.V. acknowledge the support of the Grant Agency of the Czech Republic (210/10/0467) and of the Ministry of Education of the Czech Republic (MSM0021620855).Peer reviewedPublisher PD

FT-Raman and infrared spectroscopic study of aragonite-strontianite (CaxSr1-xC03) solid solution

Synthetic aragonite-strontianite solid-solution samples have been studied using dispersive IR and FT-Raman spectroscopy. In addition to the end-members, nine samples over a range of composition from Ca0,9Sr0,1CO3 to Ca0,1Sr0,9CO3 were analysed. Carbonate anion internal modes are examined in detail by means of band-shape analysis and component fitting procedures. Positional disorder induced by the random cationic substitution results in strong increase of the halfwidth in several vibrational bands. Results obtained for the doubly degenerate modes (antisymmetric stretching and bending, v3 and v4) reveal the presence of three components both in the IR antisymmetric stretching band as well as in the Raman antisymmetric bending band. These observations are interpreted in terms of an overtone 2v4 in possible Fermi resonance with the corresponding vg fundamental in the IR spectra, and the presence of Davidov (factor group) splitting in the FT-Raman v4 band. Lattice modes in the FT-Raman spectra demonstrate weaker cohesion between the cation/carbonate/cation layers in aragonite (synth) than in strontianite (synth)

Spektroskopowa analiza ramanowska obiektów archeologicznych istotnych dla ochrony dziedzictwa kulturowego: oświecenie starożytnych tajemnic

This paper reviews the contributions of Raman spectroscopy to the non-destructive characterisation of biological materials, including the sourcing of resins and the identification of biodegradation of art and archaeological artefacts. The advantages of Raman spectroscopy for non-destructive analysis are well-appreciated. However, the ability to record molecular information about organic and inorganic species present in a heterogeneous specimen at the same time, the insensitivity of the Raman scattering process to water and hydroxyl groups which re moves the necessity for sample desiccation, and the ease of illumination for samples of very small and very large sizes and unusual shapes are also apparent. Several examples are used to illustrate the application of Raman spectroscopic techniques to the characterisation of biomaterials and for the preservation of cultural heritage through case studies in the following areas: wall-paintings and rock art, human and animal tissues and skeletal remains, fabrics, resins and ivories.W artykule omówiono przydatność spektroskopii ramanowskiej dla niedestrukcyjnej charakterystyki materiałów biologicznych, np. badanie źródeł żywic i identyfikacja biodegradacji dzieł sztuki i obiektów archeologicznych. Zalety spektroskopii ramanowskiej w niedekstrukcyjnej analizie są powszechnie uznawane. Jednakże badania dowodzą także możliwości uzyskiwania informacji molekularnych o formach organicznych i nieorganicznych obecnych równocześnie w heterogenicznych próbkach, na braku wpływu wody i grupy hydroksylowej na rozproszenia ramanowskiego co likwiduje konieczność osuszania próbek oraz łatwość analizowania próbek o bardzo małych lub bardzo dużych rozmiarach albo nietypowych kształtach. W artykule przedstawiono kilka przykładów zastosowania spektroskopii ramanowskiej do charakterystyki biomateriałów i ochrony dziedzictwa kulturalnego. Studia przypadków dotyczyły następujących obszarów: malowidła ścienne i naskalne, tkanki ludzkie i zwierzęce oraz szczątki kości, tkaniny, żywice i kość słoniowa

Ancient Textile Fibres (Chapter 19)

Textiles represent a vital element of our cultural heritage. The fibres alone can tell an intriguing tale of agricultural development, international trade and technological progress. While in an archaeological context, the fibre state may further witness the burial conditions and the effectors of decay

Proximal analysis of regolith habitats and protective biomolecules in situ by laser Raman spectroscopy: Overview of terrestrial Antarctic habitats and Mars analogs

Fourier-transform laser Raman spectroscopy in the near infrared (1064 nm) has been used to characterize a variety of key pigments and biomolecules produced by cyanobacteria and other stress-tolerant microbes in material from extreme Antarctic cold deserts analogous to martian habitats. These compounds include photosynthetic pigments and sunscreens to protect against harmful UV radiation in the light zone (chlorophyll, scytonemin, β-carotene) and photoprotective minerals, such as silica containing iron (III) oxide. Calcium oxalate mono- and dihydrate produced as a result of the biological weathering processes and stress-protective compounds, necessary to protect organisms against desiccation, freezing temperatures, and hypersalinity, such as water-replacement molecules (trehalose), are also monitored. From the results obtained using Antarctic samples, it is shown that a laser-based system can be used to characterize biomolecules in their natural state within their mineral microhabitats. Because of the similarities between the Antarctic cold desert ecosystems, which represent some of the most extreme terrestrial environmental habitats, and putative martian analogs, the laser-Raman spectrosocopic approach is proposed for the detection of former life on Mars analogs to terrestrial cyanobacteria under stress, such as stromatolites, evaporites, and endolithic communities. To this end, the spectral database that is being accumulated from laser-Raman studies of these Antarctic communities will provide a resource of potential biomarkers for future remote laser-Raman analysis on future Mars missions

Antarctic ecosystems as models for extraterrestrial surface habitats

Surface habitats in Antarctic deserts are near the limits of life on Earth and resemble those hypothesized for early Mars. Cyanobacteria dominate the transient riverbeds, stromatolitic sediments in ice-covered lakes, and endolithic communities in translucent rock. There is still no direct evidence of photosynthetic life on early Mars, but cyanobacteria are amongst the earliest microbes detectable in the fossil record for analogous habitats on Earth. Key biomolecules persist in Antarctic microbial habitats, even after extinction by excessive low temperatures, desiccation and UV-B stress within the Ozone Hole. Pigments (or their fossil residues), such as chlorophyll and the UV-protectants scytonemin, carotene and quinones, are good biomarkers. To show not only their presence but also their micro-spatial distribution in situ, we describe the use of FT–Raman spectroscopy with 1064 nm excitation to avoid autofluorescence from the pigments. We report not only the diversity of biomolecules that we have diagnosed from their unique Raman spectra of Antarctic cyanobacterial communities, but also their functional stratification in endolithic communities. Our analyses of Antarctic habitats show the potential of this remote, non-intrusive technique to probe for buried biomolecules on future Mars missions and in Antarctic Lake Vostok, > 4 km beneath the Central Ice Sheet, with implications for the putative analogous sub-ice ocean on Europa