Abstract Raman spectroscopy allows thermal maturation of carbonaceous sediments to be determined. The technique has been employed on metamorphic samples exceeding temperatures of 270°C, but recently has been shown to be effective at lower temperatures. Thermal maturation techniques commonly depend on sample size, have varying efficacies at different temperatures and in different conditions. The underlying processes are not well understood, thus data interpretation can be ambiguous. Here we show the efficacy of Raman as a low-temperature thermal marker in a thrust belt. The Bornes region, in a French Subalpine chain, provides an opportunity to test the technique against published vitrinite reflectance data and thermal modelling for the first time. In doing so we show that Raman is an effective thermal marker to temperatures as low as 75°C, has a small error and is consistent with previous work. The Raman data allow us to postulate the relative thickness of the sedimentary succession across the chain, the timing of thermal maturation and the timing and thickness variations of the over-thrust Prealpine nappe. The work establishes Raman as a low-temperature thermal marker for correlation with other techniques to ensure effective and robust interpretation, that can readily be applied to fold–thrust belts in hydrocarbon provinces.

Abstract Geological fluids are the major agents of transport of matter and heat in Earth dynamics. Unlike minerals, fluid density may vary by an order of magnitude, resulting in drastic changes in the molecular interactions. Water is a major fluid component, so it is essential to understand the response of hydrogen bonding with respect to pressure and temperature. In addition, geological fluids can be classified as complex chemical systems by a mixture of molecular compounds and ions. Thus, the study of aqueous solutions plays a fundamental role in understanding the behaviour of geological fluids. In the present chapter, focus is first placed on the use of Raman spectroscopy in the study of gases and how their spectral response changes under different pressure/temperature conditions. The ability of Raman spectroscopy to detect structural changes occurring in hydrogen-bonded systems, under thermodynamic conditions ranging from ordinary to extreme pressures and/or temperature is then discussed. Raman spectroscopy will be shown to provide invaluable information for a better understanding of the role played by geological fluids in Earth and crustal processes.

Abstract This chapter is structured to map the natural way of handling data when performing a Raman experiment, from data acquisition and organization, moving through simple data processing and towards complex chemometric methods. After a short introduction, Section 2 deals with data acquisition and organization. Section 3 addresses basic data pre-processing concepts like denoising, background removal and calibration, while the final section presents briefly the chemometric algorithms employed most often in analysing Raman data (multivariate calibration, classification methods, clustering).